Ruminants doi: 10.3390/ruminants6030066

Authors: Justin J. Delver Federico Podversich Ana Clara B. Menezes Warren C. Rusche Zachary K. F. Smith

This study evaluated the effect of limiting feed intake to 92% of ad libitum for 28 or 56 d of a 56 d finishing period on growth performance, carcass characteristics, and visceral organ mass in wethers. Thirty Polypay wethers (initial SBW = 25.6 ± 5.27 kg; 15 pens, 2 lambs/pen) were blocked by body weight and assigned to three treatments: ad libitum intake for 56 d (CON), 92% of ad libitum intake for 28 d and then ad libitum intake for 28 d (28L), or 92% of ad libitum intake for 56 d (56L). Cumulatively, DMI decreased as restriction length increased (p < 0.001), but the final SBW, ADG, and G:F did not differ between treatments (p ≥ 0.11). Hot and cold carcass weights along with carcass muscle and bone masses were lesser in 28L than CON, but 56L did not differ (p ≤ 0.04). Carcass fat mass was greatest in CON and least in 28L (p ≤ 0.04). Relative to EBW, liver mass was greatest in 28L and least in 56L (p = 0.03). Limit feeding for 56 d maintained carcass weight while increasing leanness compared to CON, whereas a 28 d restriction period reduced carcass and muscle mass, possibly due to visceral organ recovery.

Ruminants doi: 10.3390/ruminants6030065

Authors: Fernando Mata Joaquim Cerqueira Pedro Vaz Gustavo Paixão José Pedro Araújo

Accurate live-weight monitoring is important for calf management, but calibrated scales are not always available under farm conditions. This study evaluated the accuracy of a thoracic measuring tape for estimating live weight in Minhota calves and examined whether tape error was influenced by age, sex and dam parity. The dataset included 210 repeated weighing records from 68 biologically distinct calves. Scale-measured live weight was used as the reference value, and tape accuracy was assessed using signed error, absolute error, percentage error, absolute percentage error, correlation and Bland–Altman analysis. Repeated-measures regression models were used to account for multiple records from the same calf. Tape-estimated live weight was very strongly correlated with scale-measured live weight (r = 0.997). The tape showed a small average underestimation of live weight, with a mean signed error of −3.02 kg, mean absolute error of 7.79 kg, root mean squared error of 11.92 kg and mean absolute percentage error of 4.97%. Age was the main factor associated with tape accuracy. For every additional 100 days of age, signed error decreased by 5.74 kg, indicating increasing underestimation in older calves. Sex and dam parity had limited effects. The thoracic measuring tape is a useful practical tool for routine monitoring of Minhota calf growth, but age-related bias should be considered, especially in older and heavier calves.

Ruminants doi: 10.3390/ruminants6030064

Authors: Hugo Miranda Maciel Nunes Julián Andrés Castillo Vargas Susana Paula Almeida Alves Rui José Branquinho Bessa Pedro Veiga Rodrigues Paulino Moacir Evandro Lage Daniel Henrique Souza Tavares Fabrícia Rocha Chaves Miotto

The growing demand for high-quality beef has driven the selection of bovine genotypes offering superior marbling and tenderness. This study evaluated meat quality parameters in heifers from four Nellore-based genetic groups: ½ Aberdeen Angus × ½ Nellore (AN), ½ Japanese Brown × ½ Nellore (BN), ½ Japanese Brown × ¼ Aberdeen Angus × ¼ Nellore (TriBAN), and ½ Japanese Black × ¼ Aberdeen Angus × ¼ Nellore (TriJAN). Thirty-two heifers (eight/group) were finished in commercial feedlots. Samples of the longissimus thoracis muscle were analyzed for physical attributes (pH, cooking loss, shear force, marbling, water retention capacity, and colour), chemical composition, and fatty acid profile. In addition, animal performance (daily gain and final weight) was determined. A completely randomized design was used with analysis of variance followed by Tukey’s test (α = 0.05). The AN group showed the greatest final weight and daily gain (p < 0.01). There were no significant differences among genetic groups for pH, cooking loss, shear force, marbling, water-holding capacity, or colour (p > 0.05). Across all groups, the mean ultimate pH was 5.59, shear force (WBSF) averaged 41.11 N, and intramuscular fat (ether extract) content averaged 13.15 g 100 g−1, indicating desirable technological and eating-quality characteristics. Most fatty acids did not differ among treatments (p > 0.05), except for arachidonic acid (C20:4 n-6), which was present at higher concentrations (p < 0.05) in the TriBAN group than in the other genetic groups. In conclusion, despite differences in productive performance, all genotypes produced meat with consistent quality traits, including tenderness, marbling, and fatty acid profiles associated with high-quality beef.

Ruminants doi: 10.3390/ruminants6030063

Authors: Haohua Zhuang Dengke Liu Xinyue Zhang Wentao Lu Shukai Zhang Guowei Yang Jie Cao Chong Ma

This study comprised two related experiments. Experiment 1 evaluated the effects of low-temperature long-time pasteurization (LTLT, 63 °C for 30 min) on selected vitamins in bovine colostrum and mature milk. Experiment 2 independently evaluated the effects of dietary β-carotene supplementation on growth performance, fecal scores, oxidative status, cortisol concentrations, and fecal microbiota in preweaning calves. In Experiment 1, colostrum and mature milk were collected from four primiparous and four multiparous Holstein cows before and after LTLT. Concentrations of vitamin A, β-carotene, vitamin B1, vitamin B2, vitamin B9, and vitamin B12 were determined. In Experiment 2, 128 neonatal Holstein heifer calves were randomly assigned to a control group or a β-carotene-supplemented group (100 mg/day/calf) for 56 days. Growth performance, fecal scores, serum antioxidant indicators, cortisol concentrations, and fecal microbiota were evaluated. Colostrum contained substantially higher β-carotene concentrations than mature milk, particularly in primiparous cows (p < 0.001). LTLT reduced β-carotene concentrations by 30% in colostrum(p = 0.034) and significantly decreased vitamin B1 (p < 0.001), whereas the remaining vitamins were only minimally affected. Dietary β-carotene supplementation stabilized antioxidant enzyme activities, reduced serum malondialdehyde and cortisol concentrations (p < 0.001), decreased the occurrence of severe diarrhea (p = 0.046), increased the relative abundance of Blautia, and reduced Fusobacterium and Parabacteroides. Average daily gain did not differ between treatments (p = 0.154). Under the conditions evaluated in Experiment 1, β-carotene was the vitamin most affected by LTLT in colostrum. In the separate feeding experiment, dietary β-carotene supplementation affected several antioxidant indicators, reduced cortisol concentrations and the frequency of severe diarrhea scores, and altered fecal microbial composition, but did not affect average daily gain.

Ruminants doi: 10.3390/ruminants6030062

Authors: Najela Maia Chaves Fabieli Loise Braga Feitosa Louise Sarmento Martins de Oliveira Leonardo Machestropa Arikawa Lucia Galvão de Albuquerque Gregorio Miguel Ferreira de Camargo Raphael Bermal Costa

Most studies involving genomic data in animal breeding use only the effects of autosomal chromosome markers, excluding the sex chromosomes. However, the X chromosome is the second-largest chromosome in the bovine genome, and several economically important traits are sexually dimorphic, such as those related to growth. Therefore, the objective of this study was to evaluate whether there are predictive advantages for genetic parameters when including genomic markers from the X chromosome for yearling weight (YW) and postweaning gain (PWG) in Nellore cattle. Genetic parameter estimates were obtained under three scenarios: (1) only pedigree and phenotypic information; (2) pedigree, phenotypes, and autosomal chromosome markers; and (3) pedigree, phenotypes, autosomal chromosome markers, and X chromosome markers. Analyses were carried out using Bayesian inference with BLUPF90 family software version 2025. The heritability estimates obtained and their respective standard errors were 0.41 ± 0.004 for YW and 0.21 ± 0.004 for PWG. No differences were observed among the three scenarios tested for either trait. Therefore, the inclusion of the X chromosome did not influence the estimates of genetic parameters for these growth traits in Nellore cattle. Nevertheless, further molecular and genomic studies on the bovine X chromosome are still needed to explain the genetic effects and biological functions associated with this chromosome and with different traits of economic interest, as well as to justify whether to include the X chromosome in genomic prediction analyses.

Ruminants doi: 10.3390/ruminants6030061

Authors: Rene A. Corner-Thomas Kailun Zhang Fernando J. Roca Fraga Karina Neimaur Ignacio De Barbieri Paul R. Kenyon

This review used a qualitive approach to help further understand the benefits of pregnancy shearing and its potential mechanisms. A recent meta-analysis showed that pregnancy shearing increased lamb birth weight when conducted between days 42 and 100 of gestation but not after day 100; however, there was no effect on lamb weaning weight. Factors identified as potential mechanisms for the lamb birth weight response include comb type, gestation length, ewe pregnancy nutrition and feed intake, changes in ewe hormones and metabolites and altered placental development. There was, however, no single consistent parameter identified for the birth weight effect and more research is required. Shearing can potentially increase lamb survival, thermoregulatory capability and improve behaviour and ewe milk production but, again, further research is also required to confirm these. In conclusion, to maximise the chance of a birth weight response, farmers should focus on twin-bearing ewes of adequate body condition, shear with a comb that leaves a greater stubble depth and ensure ewes are offered at least pregnancy maintenance feeding levels.

Ruminants doi: 10.3390/ruminants6030060

Authors: Michal Ďuračka Lucia Urbanová Silvia Farkasová Filip Benko Sara Ataei-Nazari Eva Tvrdá

This study investigated whether miR-31-5p abundance in fresh Holstein bull semen is associated with post-thaw sperm resilience. The initial cohort comprised 36 Holstein bulls, from which 16 ejaculates representing the highest- and lowest-ranking post-thaw freezers were selected for epigenetic and molecular analyses. Fresh semen was analyzed for miR-31-5p, while BAX and BCL2 were evaluated at transcript and protein levels before and after cryopreservation. Post-thaw sperm quality was assessed using total motility, viability, JC-1 mitochondrial membrane potential, Annexin-negative spermatozoa, reactive oxygen species (ROS) and sperm DNA fragmentation. Cryopreservation significantly impaired sperm quality, increased ROS and DNA fragmentation, and shifted the molecular profile toward increased BAX and reduced BCL2. Ejaculates with superior post-thaw motility showed higher miR-31-5p levels, accompanied by better preservation of viability, mitochondrial function, non-apoptotic membrane status, lower ROS burden and DNA fragmentation after thawing. Fresh miR-31-5p was positively associated with post-thaw motility, viability, mitochondrial function, and Annexin-negative spermatozoa and negatively associated with post-thaw ROS. Our data support miR-31-5p as a potential candidate biomarker of sperm freezability in Holstein bulls.

Ruminants doi: 10.3390/ruminants6030059

Authors: Alejandro Rivera-Villegas Gabriel Romero Oliver Yaotzin Sánchez-Barbosa Pedro Hernández-Briano Octavio Martínez-Guerrero Alejandro Espinoza Octavio Carrillo-Muro Rosalba Lazalde-Cruz Daniel Rodríguez-Cordero Alejandro Plascencia

The objective of this study was to evaluate the effects of corn processing method (ground corn, GC, vs. steam-flaked corn, SFC) and daily calcium propionate (CaPr; 0 vs. 9.45 g/lamb/d) supplementation on productive performance, dietary energetics, fat deposition, and carcass characteristics in finishing lambs. Thirty-six Dorper × Katahdin lambs (44.95 ± 3.30 kg initial body weight, IBW), blocked by IBW and randomly assigned within block to a 2 × 2 factorial arrangement, were used. Diets contained 50% corn grain and treatments consisted of: (1) GC, (2) SFC, (3) GC plus CaPr, and (4) SFC plus CaPr. There were no corn processing × CaPr interactions for growth performance, dietary energetics, or observed-to-expected dietary net energy (NE) ratios. Steam-flaked corn decreased DMI (1.30 vs. 1.35 kg/d; p = 0.0036) and increased average daily gain (ADG; 0.168 vs. 0.144 kg/d), gain-to-feed ratio (G:F), and observed-to-expected dietary NE ratios compared with GC diets (p < 0.05). In contrast, CaPr supplementation increased DMI (1.35 vs. 1.30 kg/d; p = 0.0215) without affecting ADG, G:F, or observed-to-expected dietary NE ratios (p > 0.05). Steam-flaked corn increased hot carcass weight (p = 0.0339), cold carcass weight (p = 0.0241), Longissimus lumborum muscle area (p = 0.0206), and chest depth (p = 0.0368), whereas CaPr increased carcass length (p = 0.0451). Interactions between corn processing and CaPr supplementation were observed for rib fat thickness (p = 0.0491), rump fat thickness (p = 0.0272), visceral fat (p = 0.0485), perirenal fat (p = 0.0209), and shoulder tissue composition, including muscle (p = 0.0309), fat (p = 0.0438), and muscle:fat ratio (p = 0.0348). In GC diets, CaPr supplementation decreased fat deposition and increased muscle proportion, whereas in SFC diets CaPr supplementation increased fat deposition and reduced muscle proportion. Neither corn processing nor CaPr supplementation affected visceral mass (g viscera/g empty body weight). Calcium propionate supplementation decreased hindquarter yield (p = 0.0494), increased shoulder IMPS207 yield (p = 0.0494), and increased purge loss at 24 h (p = 0.0496). Water-holding capacity showed a corn processing × CaPr interaction (p = 0.0170), whereas the remaining meat-quality variables were not affected. Overall, SFC improved productive performance and dietary energy utilization, whereas CaPr increased DMI and altered fat deposition and tissue composition responses depending on corn processing method.

Ruminants doi: 10.3390/ruminants6030058

Authors: María T. Espinoza-León Itzel López-Rosas Arlette Camacho-Lizárraga Higinio Cepeda-Quintero Jesús J. Portillo-Loera Soila M. Gaxiola-Camacho José Luis Villalpando-Aguilar Arnulfo Montero-Pardo

Major fecundity (Fec) genes play a central role in regulating the ovulation rate and litter size in sheep and have become important targets for genetic improvement programs. This study aimed to systematically evaluate the global evidence regarding the association of the major fecundity genes BMPR1B, BMP15, and GDF9 with litter size through a systematic review and meta-analysis. A total of 104 studies met the eligibility criteria for the systematic review, 31 of which provided sufficient quantitative data for meta-analysis. Random-effects models were used to compare litter size among genotypes, and subgroup analyses together with meta-regression were performed to investigate the contribution of gene identity, mutation type, climatic region, and production system to the observed between-study heterogeneity. Overall, heterozygous carriers of fecundity-associated polymorphisms produced significantly larger litters than wild-type animals. Gene-specific analyses showed that BMPR1B exhibited the strongest positive association with litter size, followed by BMP15, whereas GDF9 showed no significant overall pooled effect. Meta-regression identified gene identity (Pseudo-R2 = 38.57%) and mutation type (Pseudo-R2 = 31.12%) as the principal sources of between-study heterogeneity, while climatic region and production system had no significant moderating effects. These findings provide robust quantitative evidence supporting the use of validated fecundity-associated markers, particularly BMPR1B, in marker-assisted and genomic selection programs aimed at improving reproductive performance in sheep.

Ruminants doi: 10.3390/ruminants6030057

Authors: José Ramón Díaz Marina Galvez-Lopez Esther Sendra Manuel Viuda-Martos Jordi Saldo Gema Romero

Grape pomace represents the main by-product generated during winemaking and is characterised by its richness in polyphenols, dietary fibre, residual sugars, lipids, and triterpenes. These bioactive compounds derived from grapes are known to positively influence oxidative status, metabolic balance, and animal productivity, positioning grape pomace as a promising, environmentally and economically sustainable alternative feed ingredient for conventional feed components. This research evaluated the effects of incorporating different inclusion rates (0, 6, 12, and 18% DM) of ensiled red grape pomace (RGP) into isoenergetic and isoproteic diets on the nutritional and technological characteristics of goat milk. Seventy-two Murciano-Granadina dairy goats were selected and distributed into eight homogeneous groups (n = 9 per group) based on physiological traits. Each diet was randomly assigned to two groups, and the feeding trial extended over eight weeks. After a two-week adaptation to the experimental diets, four biweekly milk samplings were performed to obtain representative bulk tank samples from each treatment group. Milk samples were analysed for gross composition, pH, mineral profile, fatty acid composition, coagulation properties, colourimetric parameters, and antioxidant capacity. The collected data were analysed using a general linear model, considering the effect of the treatment, sampling days, and their interaction (Proc. GLM, SAS v9.4). Dietary RGP inclusion had no significant effect on milk gross composition or on the antioxidant activity of the milk. However, it led to a significant reduction in milk urea content and somatic cell count, alongside improvements in the lipid profile from a human health perspective. The magnitude of the effects observed in the colourimetric parameters (<0.5 units) fell below the threshold of human visual perception and was therefore not considered relevant. RGP-fed milk also showed increased calcium and potassium concentrations, while RGP_12 milk exhibited the highest phosphorus content. In addition, the lowest RGP levels (RGP_6) reduced the rennet coagulation time while increasing milk curd aggregation rate. Despite these targeted effects, the overall milk composition remained stable, which is critical for maintaining its technological functionality.

Ruminants doi: 10.3390/ruminants6030056

Authors: Alvaro Vargas-Cázares Edgar E. Medina-Ortega Felipe A. Rodríguez-Almeida Agustín Corral-Luna José A. Martínez-Quintana Joel Domínguez-Viveros Octavio Roacho-Estrada J. Guadalupe Pérez-Álvarez Beatriz E. Castro-Valenzuela

The Raramuri Criollo (RC) cattle is recognized for its adaptability, resilience, and low feeding requirements under low-input production systems. This study compared the productive and reproductive performance of purebred RC and Angus × Raramuri Criollo (AC) heifers with Hereford × Angus (HA) heifers. Experiment I evaluated post-weaning growth, feed intake, and feed efficiency in a 56 d individual feeding trial using 10 RC, 10 AC, and 8 HA heifers after a 14 d adaptation period; heifers received the experimental diet ad libitum throughout the trial. Experiment II evaluated puberty attainment and growth development of 14 RC, 17 AC, and 11 HA heifers under rangeland with limited supplementation (RLS) and 11 RC, 16 AC, and 10 HA heifers under annual irrigated pasture (AIP). Puberty attainment was determined from two consecutive serum progesterone concentrations >1 ng/mL, and body weight, average daily gain (ADG), age at puberty (AP), and body weight at puberty (BWP) were analyzed using mixed models and Kaplan–Meier survival analysis. Under individual feeding, RC and AC heifers gained 0.56 ± 0.06 and 0.32 ± 0.06 kg/d less and consumed 40.4% and 22.0% less feed than HA heifers (p < 0.05), whereas feed conversion and residual feed intake did not differ among breed groups. Heifers developed under AIP attained puberty earlier than those under RLS (median AP: 369 vs. 546 d; logrank p < 0.001). Overall, AC heifers combined the adaptive capacity of RC cattle with the productive potential of British breeds, achieving a favorable balance among growth, feed intake, feed efficiency, and reproductive development under contrasting development conditions, supporting their use in low-input beef production systems.

Ruminants doi: 10.3390/ruminants6030055

Authors: Lilla Sándorová Katalin Nagy Szilárd Bodó Ákos Bodnár István Egerszegi Dániel Fodor Ferenc Pajor Viktor Stéger

Reliable preimplantation embryo sexing is relevant in cattle breeding; however, PCR-based Y-marker detection may be sensitive to limited DNA input and sample-type-specific properties of embryo-derived material. In this observational study, we examined assay-output patterns in a low-input multiplex PCR workflow targeting a male-specific Y-chromosome marker (MSY) together with an autosomal internal control targeting cyclin-dependent kinase 1 (CDK1). A total of 141 bovine embryo-derived samples were analyzed across three sample categories: whole embryos, cleavage-stage blastomere biopsies, and blastocyst-stage trophectoderm biopsies. Assay evaluability differed across sample categories, being highest in blastocyst-stage biopsy samples (90.6%, 29/32), intermediate in whole embryos (82.9%, 58/70), and lowest in blastomere-biopsy samples (64.1%, 25/39). Among technically evaluable CDK1-positive samples, apparent MSY-positive classification also differed across categories, with rates of 55.2% (32/58) in whole embryos, 52.0% (13/25) in blastomere-biopsy samples, and 6.9% (2/29) in blastocyst-stage biopsy samples. In a same-lysate repeat-amplification subset, overall evaluability concordance was 92.5% and overall apparent MSY-based classification concordance was 88.2%, although subgroup sizes were limited. Because no independent reference method for true embryo sex was available and sample category was structurally confounded with developmental stage, semen type, sire, and partly PCR-date structure, the findings should be interpreted as assay-output observations rather than measures of biological sex ratio or diagnostic sexing accuracy. Overall, embryo-derived sample categories showed differing assay evaluability and apparent MSY-classification patterns within this low-input PCR setting, supporting the need for sample-type-specific validation when low-cell embryo-derived samples are used.

Ruminants doi: 10.3390/ruminants6030054

Authors: Marko Cincović Nikolina Milošević Nada Plavša Jovan Spasojević Mira Majkić

Assessment of the stability of inflammatory parameters in bovine blood samples is important because it enables evaluation of the impact of preanalytical factors on biomarker preservation, standardization of sample processing and storage conditions, as well as reliable and consistent interpretation of results in diagnostic and research studies. The aim of the work was to evaluate the stability of the most common inflammatory markers in the blood of cows in early lactation. The influence of the serum–clot contacts duration and the storage of the separated serum in 24 cows, at 25 °C and 4 °C, in intervals of 0–24 h, was examined. Concentrations of interleukin 1 and 6 (IL-1, IL-6), tumor necrosis factor α (TNF-α), interferon γ (IFN-γ), haptoglobin (Hp), serum amyloid A (SAA) and extracellular heat shock protein 70 (eHsp70) were determined by ELISA method, stability was assessed by ANOVA analysis and maximum permissible instability method. Stability was determined over a range of 2–15 h for IL-1, 8–24 h for IL-6, 9–13 h for TNF-α, 10–20 h for IFN-γ, 20–24 h for Hp, 15–24 h for SAA, and 9–12 h for eHsp70. The stability was strongly dependent on temperature and sample type, with storage at 4 °C providing the highest stability in most cases, while differences between serum and serum–clot samples were analyte-specific and less consistent compared to the effect of temperature.

Ruminants doi: 10.3390/ruminants6030053

Authors: Karla Mitzue Villalobos-Arias Adrián Gloria-Trujillo María Eugenia de la Torre-Hernández Pedro Abel Hernández-García Ulises Remo Cañaveral-Martínez Germán David Mendoza-Martínez Cesar Díaz-Galván Pablo Benjamín Razo-Ortíz

Rumen methane emissions contribute to global warming and energy loss in cattle. The use of plants rich in secondary metabolites to mitigate methane emissions has been extensively studied, with varying outcomes. The primary aim of this meta-analysis was to assess the impact of secondary metabolites on methane production, productive performance, and ruminal fermentation in beef cattle supplemented with plant-based additives. In accordance with the PRISMA guidelines, 43 of the 578 studies were selected for analysis, employing random-effects models to estimate the raw and standardized mean differences (RStudio: metafor and ggplot, with significance thresholds of p ≤ 0.05 and p ≤ 0.1). Heterogeneity was evaluated using the I2 statistic, alongside a subgroup meta-regression examining variables such as dose, additive type, additive form, and forage-to-concentrate ratio. After performing Egger’s test and trim and fill analysis, it was determined that tannins reduced methane yield (g/kg DM, adjusted SDM = −0.463), increased propionate production (%, RMD = 0.066, p = 0.001), rumen pH (adjusted SMD = 0.307), and organic matter intake (RMD = 0.066, p = 0.01). Despite phenolic compounds, flavonoids, terpenes, and terpenoids successfully modulating methane production, fermentative parameters, and nutrient intake, the limited number of comparisons and publication bias suggest caution in generalizing these results. In conclusion, supplementation with plant-based additives containing tannins offers a promising nutritional strategy for reducing enteric methane emissions while maintaining beef cattle performance.

Ruminants doi: 10.3390/ruminants6030052

Authors: César Cuenca-Verde Rosa Isabel Higuera-Piedrahita Héctor Alejandro de la Cruz-Cruz Enrique Flores-Gasca María del Rocio Morales-Méndez Marco Antonio Muñoz-Guzmán Fernando Alba-Hurtado Jorge Alfredo Cuéllar-Ordaz

Haemonchus contortus is one of the most prevalent gastrointestinal nematodes in all ecosystems in Mexico, where sheep are raised on pasture, and it poses a significant threat. This study aimed to examine the surgical isolation of a Mexican H. contortus strain, its morphological and molecular characterization, and the maintenance of this strain for future research. Biological behavior and some phenotypic aspects of the adults were considered. Fecal samples were obtained from naturally infected sheep, larval cultures were performed, and a nematode-free lamb was infected. Once the infection was established, the donor sheep were euthanized, the adults recovered, and H. contortus females and males were selected. A surgical transfer from H. contortus adult to the abomasum of a receptor lamb was performed, and the beginning of the egg excretion was confirmed three days post-transfer; fecal cultures from the receptor lamb were conducted to verify the purity of the strain. After three lambs were infected with 3000, 5000, and 10,000 L3, the pre-patent period, prolificacy, and measurements of the adult stages of the strain were studied. The molecular characteristics were evaluated by qPCR; primers were designed based on NCBI genomic DNA sequences of H. contortus to amplify a 176 bp fragment, and the amplicon was sequenced for taxonomic identification. The results of this study describe biological characteristics and some phenotypic aspects of the adults, as well as eggs and infective larvae, and molecular characteristics of the isolated strain, and establish a successful methodology for isolating and maintaining a pure strain of H. contortus (FESC-strain); it can be used as a reference in experimental infections or anthelmintic resistance studies.

Ruminants doi: 10.3390/ruminants6030051

Authors: Max Silverstein Phillip A. Lancaster

Visceral organ mass is a major determinant of maintenance energy requirements in cattle, suggesting that equations to predict visceral organ mass could increase the accuracy of estimates of energy requirements. The objective of this meta-analysis was to quantify the relationships of visceral organ mass with the chemical composition of the diet, as well as animal and management characteristics. A database of 170 treatment means from 38 studies was assembled from published literature. Mixed-effects models with animal, management, and diet characteristics as fixed effects and study as a random effect were selected based on the lowest corrected Akaike information criterion (AICc) and evaluated via leave-one-trial-out cross-validation. Out of 16 organs, 15 had concordance correlation coefficient (CCC) values over 0.900, and cross-validated coefficient of determination (R2) values ranged from 0.728 to 0.967 across organs. Dry-matter intake, days on feed, and fiber-related diet characteristics (roughage level, neutral detergent fiber, and physically effective neutral detergent fiber) were the most consistently retained predictors, with crude protein and metabolizable energy concentrations being retained less frequently. These equations provide a quantitative basis for more accurate estimation of visceral organ mass in cattle.

Ruminants doi: 10.3390/ruminants6030050

Authors: Franziska Nankemann Yanchao Zhang Janina Schmidt Nicole Wente Volker Krömker

Cow-based calf rearing (dam- or foster cow-based) is gaining popularity as a relatively natural husbandry practice. However, direct udder contact by calves creates a bidirectional transmission route for pathogens. The objective of this cross-sectional study was to investigate the prevalence and concordance of mastitis-associated pathogens in the milk of cows and the saliva of corresponding calves at the time of weaning. On 15 organic dairy farms, milk samples from 269 cows and saliva samples from 403 calves were collected at weaning. Pathogen differentiation was performed via Matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF), and strain typing was additionally conducted via randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). Dominant pathogens in milk were Non-aureus-Staphylococci (NaS)/Mammaliicoccus spp. and Corynebacterium spp., and in calf saliva, NaS/Mammaliicoccus spp. (primarily M. sciuri, S. xylosus). There were a total of 12 strain concordances, exclusively in foster cow–calf pairs (Fisher’s exact test, p = 0.012). The highest observed/expected ratio was found for P. multocida (21.1). For S. aureus, strain matches were found in 3 foster cow–calf pairs across 2 farms. Direct strain concordance was generally observed rather rarely. The observed strain concordances suggest transmission between cows and calves, particularly for S. aureus and P. multocida. NaS and Mammaliicoccus spp. concordances are likely attributable to a common environmental source.

Ruminants doi: 10.3390/ruminants6030049

Authors: Alexandra M. Arellano-Correa Cristina García-De la Peña Juan Carlos Ontiveros-Chacón Annely Zamudio-López Quetzaly K. Siller-Rodríguez Verónica Ávila-Rodríguez Sergio I. Barraza-Guerrero Jorge Luis Cortinas-Salazar Judith Correa-Gómez Jesús Vásquez-Arroyo Irene Pacheco-Torres

Bovine-associated microbial communities play important roles in animal physiology, immune regulation, and mammary health. However, knowledge regarding bacterial populations associated with blood and milk remains limited in healthy dairy cattle exposed to different environmental conditions. In this study, we characterized and compared blood- and milk-associated bacterial communities from clinically healthy Holstein cows during summer and winter in an intensive commercial dairy production system located in northern Mexico using 16S rRNA metabarcoding. Significant differences in alpha and beta diversity metrics were observed according to sample type and season. Milk samples exhibited higher microbial richness and diversity than blood samples, and comparative analyses revealed significant differences in bacterial community composition between sample types and seasonal sampling periods. Bacterial communities were mainly dominated by Proteobacteria, Firmicutes, Actinobacteriota, and Bacteroidota. Differential abundance analyses identified genera associated with environmental exposure or opportunistic infections, including Staphylococcus, Streptococcus, Corynebacterium, Pseudomonas, and Acinetobacter. Overall, the observed bacterial community patterns varied according to sample type and seasonal environmental conditions, highlighting the complexity of host-associated microbial ecosystems in dairy cattle.

Ruminants doi: 10.3390/ruminants6030048

Authors: Katharina Padberg Christian Visscher Marcus Peschel Christin Unruh Dirk von Soosten Erik Bannert Patricia Mertens Liane Hüther Susanne Kersten Sven Dänicke Ulrich Meyer

A key factor in reducing nitrogen (N) emissions from dairy farms is understanding the interdependencies between N intake (NI), N excretion (Nex), and N use efficiency (NEff) in cows. This study analyzed these parameters and their interrelationships to develop predictive models. Data were collected over two years, during six feeding periods with different rations (N: 20.5–25.6 g per kilogram dry matter [g/kg DM]; metabolizable energy (ME): 10.8–12.1 megajoules per kilogram dry matter [MJ/kg DM]; net energy for lactation (NEL): 6.5–7.5 MJ/kg DM). Each period included 48 German Holstein cows (620 ± 65 kg body weight [kg BW]; first to fifth lactation). Blood, urine, feces, milk, and feed samples were collected, and individual feed intake and milk yield were recorded. NI was positively related to nitrogen in milk (NM; R2 = 0.68 **) and feces (NF; R2 = 0.49 ***). Several feeding, milk, and blood parameters showed significant correlations with NEff. These variables were used to develop two mixed-effects models. One model is based on variables available under practical feeding conditions. It includes dietary gross energy (GE), dietary crude protein (CP), milk yield, and milk protein concentration. This model shows good statistical performance in comparison to the calculated NEff (CCC = 0.78). The best explanatory model added blood parameters and further increased prediction accuracy (CCC = 0.90). In conclusion, NEff can be reliably predicted using moderately complex models. These models combine routine feeding and milk data with selected blood indicators.

Ruminants doi: 10.3390/ruminants6030047

Authors: Lwando Mbambalala Khanyisile R. Mbatha

Enteric methane (CH4) emissions from ruminants are a significant contributor to agricultural greenhouse gas emissions and represent an increasing concern in African livestock systems. This systematic review evaluates the effectiveness of tannin-rich plants as a dietary strategy for mitigating enteric CH4 emissions in African ruminant production systems. The review followed PRISMA guidelines and included peer-reviewed original studies published between 2015 and 2025 that investigated tannin-rich plant interventions in cattle, sheep, or goats within African production systems. Eligible studies comprised both in vivo feeding trials and in vitro rumen fermentation experiments. Studies were included if they reported enteric CH4 or greenhouse gas-related outcomes, while reviews, modeling studies, non-ruminant studies, and studies without CH4-related outcomes were excluded. A total of eight eligible studies were identified, all conducted in South Africa despite the Africa-wide scope of the review. Overall, tannin-rich plant interventions showed potential to reduce CH4 emissions, although the magnitude and consistency of responses varied depending on tannin type, source, inclusion level, form of administration, and dietary context. Purified and encapsulated tannin extracts generally produced more consistent CH4 reductions than crude or whole-plant sources. Responses also differed between controlled total mixed ration systems and forage-based feeding systems. However, the small number of studies and their strong geographic concentration limit broader generalization across the continent. In conclusion, tannin-rich plants show promise as a natural CH4 mitigation strategy in ruminants, but more regionally distributed and methodologically robust studies are needed across Africa to strengthen the evidence base.

Ruminants doi: 10.3390/ruminants6030046

Authors: Ganapathi Palanisamy Anitha Subramaniyan Venkataramanan Ragothaman Velladurai Chinnappillai Subash Ramu Sankar Venkatachalam Rajkumar Ramasamy Hariharan Thiruvenkatachetty Saravanan Ramasamy

This study presents the growth data of indigenous Bargur cattle calves maintained at the Bargur Cattle Research Station, Tamil Nadu, India. Bargur cattle are an endangered breed known for their adaptability to hilly environments and production potential. The dataset included 1803 weight–age records collected from 174 calves, covering measurements from birth (age code 1) to approximately 16 months of age (age code 17). In the research station database, birth weight was recorded as age code 1, with subsequent age codes representing approximately monthly weight records. To describe the growth pattern, five non-linear models, Brody, Logistic, Von Bertalanffy, Gompertz, and Generalized Weibull, were fitted to the data. Key growth parameters, such as asymptotic weight, initial weight, and growth rate were estimated, along with indicators like age and weight at inflection. Because the available records covered growth from birth (age code 1) to approximately 16 months of age (age code 17), asymptotic weight estimates should be interpreted as model-derived projections rather than observed mature body weight. Among the models evaluated, the Von Bertalanffy model showed the best overall statistical fit based on AIC, BIC, and RMSE criteria, followed by the Gompertz model. The Logistic model, although not the best-fitting model statistically, retained biological interpretability in describing early growth patterns in calves. The dataset, along with graphical outputs of growth curves and residuals, provides useful insights into the early growth trajectory of Bargur cattle and may support conservation, management, and future breeding programs.

Ruminants doi: 10.3390/ruminants6030045

Authors: Jesus A. Rojas-Reyes Abigail H. E. Ana Janae S. Bulosan Marla Fergerstrom Mark S. Thorne Melelani A. Oshiro Caleb C. Reichhardt

The objective of this trial was to evaluate the impact of an α-tocopherol injection on pre-weaning calf performance including markers of growth and behavior. Sixty-one days prior to weaning, both nursing Angus and Hereford steer calves (SC; n = 16) and Angus and Hereford heifer calves (HC; n = 28) were randomly assigned to one of two treatments: (1) no injectable α-tocopherol (CON; n = 23) or (2) 1500 IU of injectable α-tocopherol administered subcutaneously (VitE; n = 21). Average daily gain (ADG), exit velocity (EV), serum urea nitrogen, serum cortisol, and serum α-tocopherol concentrations were evaluated on d 0, 28, and 61 of the trial. Steer calves increased (p = 0.01) ADG compared to HC, with SC gaining about 13% more than HC. There was no impact (p ≥ 0.20) of injectable vitamin E on calf ADG. As the trial progressed, EV slowed (p = 0.0005) in both HC and SC regardless of treatment. Serum α-tocopherol concentrations were influenced (p = 0.04) by an interaction of treatment, sex, and time, with CON-SC being the only group that did not have serum α-tocopherol concentrations decrease throughout the trial. Overall, this trial found that a pre-weaning vitamin E injectable did not improve pre-weaning calf performance, but calf sex did.

Ruminants doi: 10.3390/ruminants6020044

Authors: Ulises Remo Cañaveral-Martínez Fernando Xicoténcatl Plata-Pérez Adrián Gloria-Trujillo Nicolas Torres-Salado Pedro Abel Hernández-García Ismael Martínez-Cortés María Magdalena Crosby-Galván María Eugenia de la Torre-Hernández Germán David Mendoza-Martínez

The effect of increasing levels of coconut oil (CO: 0, 100, 200, and 300 g/kg of supplement DM) on productive performance, feed intake, rumen fermentation, microbiota, and gene expression was evaluated in 24 calves (Bos indicus × Bos taurus; 180 ± 10 kg BW) on rotational grazing (Cynodon dactylon) in a completely randomized design (n = 6) for 112 days. Supplement intake (offer–refusal) and forage intake (external marker: chromium) were measured. On day 112, rumen fluid (fermentation profile, protozoa, and metagenomic analysis: 16S rRNA V3-V4) and total blood (DNA microarray: M22k) were collected. Genomic analyses were performed by comparing the control vs. the group with the best productive response. For statistical analysis, SAS PROC GLM (initial weight as a covariate), orthogonal polynomials, the Tukey test, and Spearman correlation were used, considering significant effects (p ≤ 0.05) and trend (p ≤ 0.1). The inclusion of 200 g CO/kg supplement DM showed the best average daily gain (p = 0.018; +0.139 kg/d) with the highest retained energy (p = 0.02; +0.631 Mcal/d) versus the control group. In the rumen, propionate increased (p ≤ 0.05), while protozoa decreased (p < 0.0001) and the methanogenic archaea tended to decrease (Methanobacteriaceae −44%, p = 0.08; Thermoplasmatales −35%, p = 0.06). At the transcriptional level, 19 hub genes were modulated by CO, suggesting a lower intracellular signaling (cAMP-PKA-CREB) associated with a lower stress condition and better energy metabolism regulation. In conclusion, 200 g CO/kg supplement DM is a viable strategy for improving the productive performance of livestock in tropical systems.

Ruminants doi: 10.3390/ruminants6020043

Authors: Andrei Lucas Rebelatto Brunetto Luisa Nora Charles Marcon Guilherme Luiz Deolindo Luiz Eduardo Lobo e Silva Roger Wagner Gilberto Vilmar Kozloski Aleksandro Schafer da Silva

The use of exogenous enzymes in feedlot cattle nutrition has been investigated as a strategy to increase nutrient utilization efficiency and productive performance. The objective of this study was to evaluate the effects of including arazyme, an exogenous metalloprotease, in the diet of feedlot beef cattle on zootechnical performance, hematological parameters, serum biochemical biomarkers, ruminal fermentation, and apparent nutrient digestibility. Twelve male Holstein cattle, with an average initial body weight of 352.5 ± 20.6 kg, were distributed in a completely randomized design with two treatments: control (no additive) and basal diet with arazyme (0.67 g/kg of dry matter consumed) for 63 days. The diet was formulated with a forage/concentrate ratio of 40:60. Although the sample size was small, the inclusion of arazyme proved effective under these conditions, with animals receiving the enzyme showing greater total weight gain, higher average daily gain, and better feed conversion, without affecting dry matter intake. No significant changes were observed in hematological parameters or in most serum biochemical biomarkers, indicating an absence of adverse effects on the metabolic or hepatic health of the animals. Higher total concentrations of volatile fatty acids in the rumen, particularly acetic, propionic, and butyric acids, as well as a higher ruminal pH on day 63, may be related to the enzyme’s action. Additionally, the apparent digestibility of crude protein and neutral detergent fiber was higher. Therefore, the inclusion of arazyme in the diet of feedlot cattle may be a promising alternative for improving digestive efficiency and intensifying ruminal fermentation, potentially resulting in improved productive performance. Future research with a larger number of replicates and different doses of the additive is necessary to understand its action.

Ruminants doi: 10.3390/ruminants6020042

Authors: Kassya da Silva Pontes Gabrielle de Melo Oliveira Henrique Nunes Parente Michelle de Oliveira Maia Parente Francisco Naysson de Sousa Santos Juliana dos Santos Lima Talita Raquel Rodrigues da Silva José Anderson da Silva Francisco Allan Leandro de Carvalho Fleming Sena Campos Glayciane Costa Gois

Parkia platycephala pod (PP) is a native feed resource with good nutritional value that can be included in sheep diets as a potential alternative ingredient without impairing the meat quality. Thus, the aim of this study was to evaluate the effect of two feeding strategies differing in forage source and corn processing form, including the use of Parkia platycephala pod and whole corn grain, on the physicochemical characteristics, proximate composition, and mineral profile of sheep meat. For this, the Semimembranosus muscle from the hind legs of twelve castrated male Dorper × Santa Inês sheep was evaluated. The animals were fed two diets: diet 1—without Parkia platycephala pod (30% Tifton hay + 20% ground corn)—and diet 2—with Parkia platycephala pod (30% Parkia platycephala pod + 0% ground corn). A completely randomized design with two treatments and six replicates was used. There was no effect of diet on the physicochemical characteristics, proximate composition and mineral profile of the Semimembranosus muscle (p > 0.05). Therefore, the inclusion of Parkia platycephala pod in sheep diets is recommended, as it does not alter meat quality.

Ruminants doi: 10.3390/ruminants6020041

Authors: Pengyu Huang Xiu Su Jie Cao

Some dairy cows develop postpartum hypocalcemia because they cannot adapt to the drastic loss of blood calcium during the periparturient period. Parathyroid hormone (PTH) maintains calcium homeostasis by regulating bone calcium mobilization, gastric and intestinal calcium absorption, and renal calcium reabsorption. Traditionally, dysregulation of PTH has been considered the main cause of this disorder. Recent studies have confirmed that parathyroid hormone-related protein (PTHrP) secreted by the mammary gland is also involved in calcium homeostasis by promoting bone resorption. Based on existing research evidence and cross-species comparisons, this paper analyzes the effects of differences in mammary calcium output and compensatory mechanisms among various mammals on the risk of postpartum hypocalcemia, with a particular focus on processes related to bone resorption and bone formation. It further explains the pathogenesis of postpartum hypocalcemia in dairy cows by examining the roles of the mammary–brain–bone axis, PTH, and PTHrP in bone resorption and bone formation in these animals.

Ruminants doi: 10.3390/ruminants6020040

Authors: Walter Weidel Lilla Sándorová Evelin Gál Blanka Metz Gábor Lukács Péter József Polgár Péter Póti Ferenc Pajor

Maintaining udder health and milk quality is important in dairy goat production; however, the interpretation of somatic cell count (SCC) in goats is complicated by physiological and non-infectious factors. This study evaluated the associations among udder and teat morphological traits, SCC, bacteriological status, and udder surface temperature in clinically healthy Saanen dairy goats. Udder conformation was assessed using a linear scoring system in multiparous goats (n = 70). Composite milk samples were collected at three lactation stages for SCC and milk quality analysis, whereas separate half-udder milk samples were used for bacteriological examination. Udder surface temperature was measured using infrared thermography (IRT) at the final sampling time point. Stepwise multiple regression analysis was applied to identify udder and teat traits associated with log-transformed SCC. The results showed considerable variation in udder conformation, with the greatest deviations observed for teat placement. Fore udder attachment, udder cleft, teat length, and teat form were significantly associated with SCC, with stronger attachment, a more distinct udder cleft, shorter teats, and a more cylindrical teat shape being associated with lower SCC. Bacteriological examination detected mastitis-associated bacteria in 45.0% of half-udder samples, mainly coagulase-negative Staphylococcus spp. and Corynebacterium spp., while the proportion of obligate udder pathogens was highest in the >2,000,000 cells/mL SCC category. Bacteriologically positive udder halves showed slightly higher surface temperatures than bacteriologically negative udder halves (p < 0.05), whereas no significant differences in udder surface temperature were observed among SCC categories. These findings suggest that udder morphology is associated with SCC and may be useful in phenotypic udder health assessment. IRT may provide complementary information on bacteriological status under standardized conditions, but its diagnostic value in dairy goats requires further validation in larger, longitudinal studies.

Ruminants doi: 10.3390/ruminants6020039

Authors: Alejandro Rivera-Villegas Lexiles Eli Matute-Guevara Oliver Yaotzin Sánchez-Barbosa Pedro Hernández-Briano Octavio Martínez-Guerrero Octavio Carrillo-Muro Rosalba Lazalde-Cruz Daniel Rodríguez-Cordero Beatriz Isabel Castro-Pérez Alejandro Plascencia

Limited empirical evidence is available validating the energy value assigned to steam-flaked corn (SFC) for small ruminants in current NRC feeding standards. Therefore, the objective of this study was to evaluate the effects of corn processing, including steam-flaking, on growth performance, dietary energetics, visceral fat deposition, and carcass characteristics of finishing lambs. Forty-eight Dorper × Katahdin ram lambs (42.0 ± 0.27 kg initial body weight) were assigned to one of four treatments (n = 12 per treatment) and fed high-concentrate diets for 45 d containing 50% yellow corn grain. Treatments differed only in the form of corn presentation: whole corn (WC), cracked corn (CC), ground corn (GC), or SFC. Cracked corn was produced using a roller mill without a sieve (mean particle size 4 to 6 mm), whereas ground corn was processed through a 3 mm sieve (mean particle size 1 to 2 mm). For SFC, WC was steamed for 20 min at approximately 102 °C before rolling, and flake density was adjusted to 0.36 kg/L by roller tension. Dry matter intake was 10.1% greater in SFC than in WC (p = 0.020), whereas CC and GC showed intermediate responses. Final body weight (+4.7%), average daily gain (+30.8%), and observed dietary net energy for maintenance (NEm; +10.4%) were greater in SFC than in GC (p < 0.05), whereas WC and CC showed intermediate responses. Gain-to-feed ratio was greater in SFC than in GC and CC (p = 0.028), representing increases of 24.6% and 18.2%, respectively. Empty body weight and visceral fat deposition were also affected by treatment (p < 0.05), with greater visceral fat deposition in SFC and CC than in GC, whereas WC showed intermediate responses. Steam-flaked corn increased longissimus lumborum muscle area by 17.7% relative to GC (p = 0.048) and increased perirenal fat deposition relative to WC, CC, and GC (p = 0.048). However, most carcass characteristics and meat quality variables were not affected during the 45 d experimental period (p > 0.05). Using a replacement technique, estimated NEm values (Mcal/kg) for CC, GC, and SFC were 2.00, 1.88, and 2.24, respectively. The NEm value for SFC was in close agreement (2.24 vs. 2.30 Mcal/kg) with current feeding standards, whereas dry-processed corn showed lower estimated NEm values (p = 0.025), representing reductions of 9% and 17% for CC and GC, respectively. In conclusion, SFC improved growth performance and dietary energy utilization relative to GC, while producing limited effects on carcass-related responses under the conditions of this 45 d study.

Ruminants doi: 10.3390/ruminants6020038

Authors: Maryam Amini Torghabeh Marzieh Hajmohammadi Giovanni Buonaiuto Damiano Cavallini Reza Valizadeh Seyed Hadi Ebrahimi

This study evaluated the effects of partially replacing inorganic copper, zinc, and manganese with hydroxychloride or methionine-bound organic sources on growth performance, antioxidant status, serum mineral concentrations, and mineral utilization in finishing Baluchi lambs. Twenty male ram lambs were randomly assigned to four dietary treatments for 60 days: a control group without supplemental minerals (CTR), a sulfate group receiving 100% of supplemental minerals as sulfates (SULF), a hydroxy group receiving 70% sulfates and 30% hydroxychloride sources (HYDRO), and an organic group receiving 70% sulfates and 30% methionine-complexed minerals (ORG). All supplemented diets were formulated to provide similar total concentrations of Cu, Zn, and Mn in accordance with NRC requirements. Growth performance and feed intake did not differ significantly among treatments (p > 0.05). Serum mineral concentrations were affected by dietary treatments (p < 0.0001), with lower Zn and Cu concentrations observed in the ORG. Urinary Mn excretion was higher in ORG (p = 0.007), whereas Zn and Cu excretion were not significantly affected. Apparent mineral absorption was not significantly different among treatments, although numerical variation was observed. Antioxidant parameters were influenced by mineral source, with higher glutathione peroxidase activity and total antioxidant capacity in ORG and HYDRO groups (p < 0.0001). These findings suggest that partial replacement of inorganic trace minerals with hydroxychloride or organic sources can modulate antioxidant status and mineral metabolism without affecting growth performance, highlighting the potential of mixed-source supplementation strategies in practical feeding systems.

Ruminants doi: 10.3390/ruminants6020037

Authors: Yolanda Romero Emmanuel Alexander Sessarego René Pinazo-Herencia Juancarlos Cruz-Luis

Goat production in Peru is primarily carried out under extensive systems shaped by climatic variability, forage seasonality, infrastructure limitations, and persistent sanitary pressure. In this context, Creole goats represent a strategic animal genetic resource due to their capacity to adapt to arid and high-Andean environments. This review integrates the available evidence on production typologies in the main goat-producing regions of the country, the major sanitary and structural bottlenecks, and the state of the art of genomic, multi-omics, and reproductive biotechnology tools applicable to goats. It discusses how the transition from traditional markers to SNP genotyping, together with functional approaches such as microbiome analysis, transcriptomics, and proteomics, can contribute to understanding the biological basis of complex traits related to resilience, feed efficiency, and reproductive performance. Likewise, the potential of precision livestock farming to generate longitudinal phenotypes and strengthen genetic improvement programs in low-input systems is highlighted. Finally, priorities and considerations are outlined to advance the integration of phenotyping, genomics, and reproductive biotechnologies in extensive contexts, with emphasis on the generation of systematic data, interinstitutional coordination, and technology transfer aimed at the sustainability and conservation of goat resources. These insights may also inform genetic improvement strategies in other developing countries facing similar environmental and structural constraints in low-input goat production systems, particularly in arid and semi-arid regions.

Ruminants doi: 10.3390/ruminants6020036

Authors: Rui Zhao Siqi Chen Qingjie Jiao Xinyan Zhu Haiyan Jia Lei Hou Dan Wang Jiaqing Hu Jianmin Wang Tianle Chao

Sheep litter size is of major economic importance, yet its polygenic nature and low heritability limit the effectiveness of traditional selection methods. Following PRISMA guidelines, this systematic review integrated genome-wide association study (GWAS) evidence for sheep litter size and prioritized candidate genes. Four databases were searched, yielding 24 eligible studies comprising a total effective analytical sample of 7618 animals from 98 breeds/populations across nine countries. Following standardized re-annotation of genomic coordinates, 245 significant variations and 316 candidate genes were extracted. Gene prioritization using ToppGene identified 96 high-priority genes, including 10 core genes: GRIN2A, DLG2, FLT4, ESR2, AMH, ALK, INHBB, NF1, CAMK2D, and ERCC2. These genes collectively operate through four functional axes: the gonadal axis regulation, follicular development, hormonal signal transduction, and DNA damage repair. Functional enrichment analysis revealed significant involvement in protein binding and metal ion binding. Marked breed-specificity was observed, with only the BMPR1B (FecB) locus replicated across three studies. Key limitations include restriction to English-language publications, small median sample sizes in the included studies, and the inherent bias of ToppGene training genes toward previously reported loci. These findings clarify the molecular genetic architecture of sheep litter size and provide a validated candidate gene framework to support precision genomic breeding strategies.

Ruminants doi: 10.3390/ruminants6020035

Authors: Huey Yi Loh Terry E. Engle

Seven Rambouillet-crossbred wethers were utilized to examine the impact of copper (Cu) supplementation on plasma, bile, liver, duodenum, jejunum, and ileum tissue Cu concentrations and Cu trafficking proteins abundance in the duodenum and liver. Wethers were assigned to one of two treatments: (1) control: no supplemental Cu and (2) +Cu: 12 mg of supplemental Cu/kg DM. After receiving treatments for 29 days, all wethers were harvested, and blood, bile, liver, duodenum, jejunum, and ileum samples were collected for Cu concentration analysis. Additional duodenum and liver samples were collected for proteomic analysis. Animals in the +Cu group had a greater (p < 0.02) Cu concentration in plasma, liver, and jejunum, but a lesser (p < 0.01) ileum Cu Concentration compared to controls. Duodenum and bile Cu concentrations and protein abundance for Cu trafficking proteins in the duodenum and liver were similar (p > 0.10) across treatments. In the +Cu group, 23 and 5 proteins were unique to the duodenum and liver, respectively, while the control group had 20 and 28 unique proteins in those tissues. These data indicate that known proteins responsible for Cu trafficking were not changed by the dose of Cu supplementation, ultimately allowing Cu to accumulate in the liver.

Ruminants doi: 10.3390/ruminants6020034

Authors: Luiz Henrique Tolentino Santos Virgílio Mesquita Gomes Edilane Aparecida da Silva Angelo Herbet Moreira Arcanjo Fernanda de Kássia Gomes José Reinaldo Mendes Ruas Thaís Eleonora Santos Sousa Alvimara Felix dos Reis Michele Gabriel Camilo Lívia Loiola dos Santos Féres Luiz Fernando Rodrigues Féres Fernando Oliveira Franco

This study assessed the productive and structural traits of the forage canopy and the performance of heifers grazing Marandu grass pastures overseeded with winter forages during the dry–wet transition in a tropical region. A completely randomized split-plot design with three replicates was used to compare three systems: Marandu grass overseeded with Oats and Ryegrass; Marandu grass overseeded with Oats and Clovers; and Marandu grass in monoculture. Holstein × Gyr heifers, averaging nine months of age with an initial body weight of 225.42 ± 50.27 kg, were managed under irrigated rotational grazing, with two days of occupation and 28 days of rest. Measurements were taken over three grazing cycles. Total forage mass and Marandu grass mass increased in the final cycle, with no differences among systems. The proportion and mass of winter forages did not differ between treatments, although overseeded pastures maintained about one-third of their composition as winter species. Animal performance was similar across systems, with greater body weight observed at the end of the experimental period. In conclusion, overseeding winter forages in irrigated Marandu grass pastures does not increase forage production or animal performance but does promote botanical diversification, with Oats showing better adaptation under these conditions.

Ruminants doi: 10.3390/ruminants6020033

Authors: Sharleen Mae Dela Cruz Gabriel Aivhie Jhoy Escuadro Cuanang Therese Patricka Cinense Cailipan Johnmel Asuncion Fabros Daphne Corrine Castro Corpuz Lawrence Pascual Belotindos Ma. Anita Mascarenas Bautista Lilian Pagaduan Villamor

The highly compact chromatin and naturally fragmented RNA content of bovine sperm make it difficult to obtain sufficient total RNA for transcriptome sequencing. Bovine sperm studies have mostly adapted the somatic-cell protocol and used generic kits. To date, no commercial extraction kit is available for total RNA from sperm. These limitations prompted optimization of a sperm total RNA isolation protocol, tested using both fresh and cryopreserved sperm. Ejaculates were collected from two Girolando bulls (Bos taurus × Bos indicus) and were subsequently processed for cryopreservation. In total, eight RNA extraction protocols were tested, namely four TRIzol®-based (GP) protocols and four spin-column (SC) methods. Across both fresh and cryopreserved sperm, Protocol D of SC protocols (SC-D) was the most suitable choice for total RNA sequencing. For fresh sperm, ~25–29 million filtered reads were obtained, and cryopreserved sperm yielded ~83–125 million filtered reads, indicating that cryopreserved sperm is also a good source of sperm RNA based on initial sequencing metrics. By pinpointing SC-D as the optimal balance in terms of yield and sequencing performance, and by identifying practical solutions for DNA carryover and storage-related duplication, the study’s results provide a streamlined protocol and quality control framework for total RNA sequencing of Girolando sperm.

Ruminants doi: 10.3390/ruminants6020032

Authors: Thaintip Kraiprom Hakim Jehdo Sitthisak Jantarat Umaporn Pastsart

This study evaluated the effects of replacing soybean meal with cashew nut roasting residue (CNRR) on feed intake, nutrient digestibility, rumen fermentation, blood metabolites, and economic efficiency in lactating crossbred Saanen goats. Fifteen does were assigned to a completely randomized design with three treatments: 0% CNRR (T1), 10% replacement of soybean meal protein (T2), and 20% replacement (T3). Goats were fed pangola hay ad libitum and concentrate according to milk yield (1:2). Total dry matter, organic matter, crude protein, and fiber intake were not affected by dietary treatments (p > 0.05). However, crude protein digestibility decreased from 68.83% in the control group to 52.72% and 51.21% in the CNRR treatments (p < 0.05). Rumen pH and total volatile fatty acids remained within normal physiological ranges, suggesting stable rumen fermentation. Blood parameters, including packed cell volume, glucose, and blood urea nitrogen, were not influenced by CNRR supplementation (p > 0.05). Economic analysis showed reduced feed cost with increasing CNRR inclusion. In conclusion, CNRR can replace soybean meal protein at rates of up to 20% without affecting feed intake, ruminal pH, or measured blood metabolites; however, crude protein digestibility was reduced, indicating that dietary formulation may require adjustment.

Ruminants doi: 10.3390/ruminants6020031

Authors: Maria de Aires Pereira Alexandra Lameira Baptista Mariana Rosário Ana Carolina Ferreira Rita Cruz Fernando Esteves Nuno Santo Rui Fragona Daniel Correia Carolina Figueiredo João Serejo João Castelo Branco Ana Fernandes Luís Figueira Pedro Carreira Pedro Caseiro Madalena Malva Alda F. A. Pires

There is growing concern that antimicrobial use (AMU) in livestock may contribute to antimicrobial resistance (AMR) in humans and lead to the consumption of animal-derived foods contaminated with antimicrobial residues. As stakeholders in the livestock industry, farmers must participate in the joint effort to reduce AMU. This cross-sectional study, based on a survey questionnaire, was conducted to evaluate the biosafety measures implemented on small ruminant farms and to assess the knowledge, attitudes and practices (KAP) of small ruminant farmers regarding AMU, AMR and residues. The mean biosafety score obtained was 8.4 points on a 0–17 scale. Some biosafety measures appeared difficult to implement, namely vehicle disinfection, requiring visitors to change clothing and footwear at the farm entrance, cleaning and disinfecting farm facilities, using high-pressure washing equipment, and requiring employees to change clothing and footwear upon entering the farm. Although farmers self-reported moderate levels of knowledge (4.9 points on a 0–7 scale) and positive attitudes (5.8 points on a 0–7 scale), significant gaps in knowledge about antibiotics and antimicrobial stewardship persisted. Practices received lower scores (4.7 on a 0–7 scale), especially regarding medication recording, leftover antibiotic management, and waste disposal. Cluster analysis identified distinct farmer profiles with different patterns of knowledge and practices. These findings underscore the importance of considering farmer heterogeneity when designing interventions aimed at improving AMU.

Ruminants doi: 10.3390/ruminants6020030

Authors: Adrián Muñoz-Cuautle María Esther Ortega-Cerrilla Jorge Hernández-Bautista Javier Suárez-Espinosa José Vian Ricardo García-Barojas Pedro Zetina-Córdoba

The objective of this study was to evaluate the productive performance, ruminal fermentation, in vivo digestibility, carcass yield, and physicochemical variables of meat when bovine rumen content (BRC) was included in the diet of lambs. Thirty-six Pelibuey-Dorper crossbred lambs of both sexes, with an average weight of 19.5 ± 1.5 kg, were used in a generalized randomized block design with the sex of the lambs as a blocking factor with four treatments: BRC0, BRC15, BRC30, and BRC45, corresponding to 0%, 15%, 30%, and 45% BRC inclusion in the diet, respectively. The results indicate that the dietary effect was not significant for any of the evaluated variables, whereas sex showed significant differences in final body weight, average daily gain, dry matter intake, and hot and cold carcass yield. Although specific treatment-sex combinations significantly influenced productive performance variables such as average daily gain, dry matter intake and ruminal fermentation parameters, such as propionic acid, there is no consistent evidence that the inclusion of bovine rumen content promotes superior productive performance or carcass quality in fattening lambs.

Ruminants doi: 10.3390/ruminants6020029

Authors: Elizabeth Calderón-Garay Alfredo Estrada-Angulo Beatriz I. Castro-Pérez Yesica J. Arteaga-Wences Jorge L. Ramos-Méndez Elizama Ponce-Barraza Jesús D. Urías-Estrada Daniel A. Mendoza-Cortez Alberto Barreras Alejandro Plascencia

Several studies have shown that supplementation with 100 to 130 mg of 3-nitrooxypropanol (3-NOP)/kg diet acts as a mitigating factor of enteric CH4 production in ruminants. From an energy perspective, this effect could indicate improved feed energy utilization. Feed additives that reduce the acetate-to-propionate molar ratio and/or CH4 production generally increase the efficiency of feed energy utilization and can alleviate the negative impact of high ambient heat loads on ruminant productivity. In seeking to test this assumption, the impact of supplementing 3-NOP in growing–finishing diets was evaluated in 24 intact male lambs (31.92 ± 3.77 kg). The experiment lasted 61 days. Treatments consisted of supplementing a total mixed growing–finishing diet (30:70 forage-to-concentrate ratio) with zero or 115 mg 3-NOP/kg diet. Lambs were assigned to 12 pens (two lambs/pen, six replicates per treatment). The temperature–humidity index (THI) during the experiment averaged 83.37 ± 6.4. The inclusion of 3-NOP tended to increase final weight (2.6%, p = 0.06) but increased dry matter intake by 10.6% (p = 0.03), thus decreasing the efficiency of dietary net energy utilization by 2.3% and 3%, respectively (p = 0.04). Lambs fed with 3-NOP showed greater (6.2%, p = 0.04) carcass weight and dressing percentage (3.3%, p = 0.03) without effects on the tissue shoulder composition. Supplemented lambs showed lower gastrointestinal (GIT) fill (9.3%, p = 0.02) and greater (1.3%) empty body weight (EBW, p < 0.01). Visceral organ mass (expressed as g/kg EBW) was not affected by 3-NOP supplementation. It was concluded that supplemental 3-NOP did not improve feed efficiency nor the efficiency of dietary energy utilization, but did improve carcass weight and dressing percentage in lambs fattened under high ambient heat load. The greater carcass weight observed in the present experiment was due mainly to a tendency for a greater final weight (p = 0.06) for 3-NOP lambs, whereas the improvement in dressing percentage was due mainly to a lower (p = 0.02) GIT fill. It is crucial to highlight that this is a pioneering study on the effect of 3-NOP on the productive efficiency of lambs subjected to high ambient heat loads. It is also important to note that enteric methane production was not measured in this experiment. Although the doses used in this experiment have consistently reduced methane production in several studies conducted under favorable climatic conditions, we cannot precisely determine the role of CH4 production in the dietary net energy efficiency observed in lambs that received 3-NOP. The results presented here provide a basis for future research evaluating the anti-methanogenic and productive responses to the use of 3-NOP under high ambient temperature conditions.

Ruminants doi: 10.3390/ruminants6020028

Authors: Suzana Rossato Feltrin Karine de Vargas Aires Amanda Luiza Prante Ana Paula da Silva Carlos Miguel Staudt Manuela Brauner Freitas Carolina dos Santos Amaral Luis Fernando Schütz Valério Marques Portela Alfredo Quites Antoniazzi

The Hippo pathway effector Yes-associated protein (YAP), acting through TEA domain (TEAD) transcription factors, regulates transcriptional programs in ovarian tissues; however, its role in interferon tau (IFNT) signaling within bovine luteal cells has not been investigated. This study aimed to determine whether YAP-TEAD interaction is required for IFNT-induced interferon-stimulated gene (ISG) expression in primary bovine luteal cells and to perform an exploratory assessment of selected receptor genes (ITGB1, GRP78, VEGFR2). Primary luteal cells were treated with recombinant ovine IFNT (roIFNT; 1 ng/mL) in the presence or absence of verteporfin (VP; 0.1, 0.5, or 1.0 µM), a pharmacological YAP-TEAD inhibitor, and mRNA expression was quantified by RT-qPCR. VP dose-dependently suppressed YAP target genes (YAP1, CTGF, ANKRD1) and reduced roIFNT-induced expression of MX1, MX2, and OAS1, whereas ISG15 was unaffected. Steroidogenic gene expression (3β-HSD, P450scc, StAR) remained unchanged across treatments, indicating preserved cell viability. Among the exploratory receptor endpoints, VP decreased ITGB1 and increased GRP78 at the highest concentration, while VEGFR2 was unaffected. These findings indicate that YAP-TEAD activity contributes to IFNT-induced ISG responsiveness in bovine luteal cells, with preliminary evidence of effects on integrin-mediated signaling pathways.

Ruminants doi: 10.3390/ruminants6020027

Authors: Norakamol Laorodphan Thanatsan Poonpaiboonpipat Tossaporn Incharoen Suban Foiklang Anusorn Cherdthong Paiboon Panase Nattapat Chaporton Payungsuk Intawicha

Milk production in tropical smallholder systems is constrained by limited high-quality roughage during the hot–dry season. Sweet sorghum silage is drought-tolerant and may replace corn stover silage. Twelve Holstein–Friesian crossbred cows were assigned to the same commercial concentrate plus either corn stover silage or sweet sorghum silage as the primary roughage source (n = 6 per diet). Intake, apparent digestibility, milk yield and composition, and feed-use efficiency were evaluated on day 15 and 30 and analyzed using linear mixed-effects models with cow as a random effect. Compared with corn stover silage, sweet sorghum silage increased dry matter intake (p < 0.05) and improved the digestibility of fibre fractions, including crude fibre, NDF and ADF (p ≤ 0.003), while crude protein- and nitrogen-free extract digestibility were not different (p > 0.05). Milk yield, 4% fat-corrected milk, energy-corrected milk, and feed-use efficiency indices were unaffected by silage source (p > 0.05). Milk protein concentration was higher with sweet sorghum silage (treatment effect p < 0.05), whereas milk fat and lactose were unchanged. Sweet sorghum silage can therefore replace corn stover silage in tropical dairy diets, improving intake and fibre utilization without compromising milk output.

Ruminants doi: 10.3390/ruminants6020026

Authors: Chollada Buranakarl Sumonwan Chamsuwan Tien Thi Phuong Vo Sarn Settachaimongkon Kunaporn Homyog

Environmental temperature-induced metabolic changes in dams can be reflected by alterations in metabolomic and fatty acid profiles in colostrum. The colostrum from 13 Black Bengal (BB) dams was collected on the day of parturition at two consecutive parities during the hot conditions (HCs) of summer or rainy seasons and the cold conditions (CCs) of winter. The metabolomic and fatty acid profiles were analyzed using nuclear magnetic resonance (NMR) and gas chromatography–mass spectrometry, respectively. The results showed significantly higher sarcosine, tyrosine, citrate, succinate, galactose, acetylglucosamine, carnitine, choline, glycerophosphocholine, and trimethylamine N-oxide during CCs than HCs; potential discriminant metabolites according to VIP scores were sarcosine, succinate, and choline. Colostrum from CCs had significantly lower levels of saturated fatty acids (SFAs), including butyric acid (C4:0), myristic acid (C14:0), and pentadecanoic acid (C15:0), but higher omega-9 monounsaturated fatty acids (MUFAs), especially oleic acid (C18:1n9c), elaidic acid (C18:1n9t), and eicosenoic acid (C20:1n9), than in HC. Linoleic acid (C18:2n6c) and the omega 6/omega 3 PUFA ratio were higher during CCs than HCs. It is concluded that a metabolic shift for nutrient utilization occurs, from glucose during HCs toward fat during CCs, which may not be due to the diet but rather neurohumoral alterations occurring during temperature adaptation.

Ruminants doi: 10.3390/ruminants6020025

Authors: Mailin Vasconcelos dos Santos Lima Emmanuel Emydio Gomes Pinheiro Núbia Amorim Oliveira Rafael Henrique de Tonissi e Buschinelli de Goes Claudia Andrea Lima Cardoso Adriana Regina Bagaldo

This study evaluated the effects of including palm kernel oil in the diets of pasture-raised sheep on carcass characteristics, meat quality, and fatty acid profiles. A completely randomized design with four treatments was used, consisting of 0, 20, 40, and 60 g/kg of palm kernel oil in the dry matter of the supplement, with eight replicates. Thirty-two uncastrated Santa Inês sheep, with an average initial body weight of 23.2 ± 2.6 kg, were used in this study. The animals were kept on Aruana grass (Panicum maximum (syn. Megathyrsus maximum) cv. Aruana) pastures under continuous stocking for 59 days (preceded by 15 days of adaptation), with each one fed supplements (1.4% of body weight) at 8 am. At the end of the experimental period, the animals were slaughtered in a commercial slaughterhouse for carcass and meat quality evaluation. The inclusion of palm kernel oil had a decreasing linear effect on hot and cold carcass weight (p = 0.0403) (p = 0.0398), but it did not affect hot or cold carcass yields or carcass morphometric measurements, commercial cut weights, pH, or loin area (p > 0.05). However, it affected the color of the L. lumborum muscle, showing an increasing linear effect on yellow intensity (b*) (p = 0.002) and on the centesimal composition, with an increasing linear effect on ether extract content (p = 0.006). Shear force, cooking loss, and water-holding capacity were not affected (p > 0.05). Fatty acid profiles, the atherogenicity and thrombogenicity indices, and the ratio of hypocholesterolemic to hypercholesterolemic fatty acids (h:H) were also unaffected by the inclusion of palm kernel oil (p > 0.05). The inclusion of up to 60 g/kg of palm kernel oil in the diets of pasture-raised sheep had an effect on carcass weight but not yield. It also had an effect on the color and chemical composition of L. lumborum muscle, but these changes did not compromise the overall quality of the meat.

Ruminants doi: 10.3390/ruminants6020024

Authors: Olesya Yatsyk Alexander Krivoruchko Antonina Skokova Elena Safaryan Elena Budanova Anastasia Kanibolotskaya

MYO16 has previously been identified as a candidate gene in studies of meat productivity in sheep, but its complete sequence and the potential impact of polymorphisms on the functional properties of the gene in sheep remain understudied. The aim of this study was to analyze genetic variation in the MYO16 gene region in sheep and to identify polymorphisms that, according to bioinformatic prediction, are capable of changing the amino acid sequence of the protein or are associated with allele-specific differences in transcription factor binding motifs potentially significant for gene regulation or protein structure. Whole-genome sequencing was performed for genomic DNA from Manych Merino rams (n = 30) on an Illumina NovaSeq 6000 platform. Variants within the MYO16 region were extracted and annotated. For each variant, ±30 bp reference and alternative sequences were scanned with FIMO using the JASPAR 2020 Vertebrates PWMs to detect allele-specific gain or loss of significant motif hits. TFLink (Mus musculus) was used to retain only TFs with MYO16 listed as a target. In the MYO16 gene region, 10,318 variants were detected. The coding region contained 54 SNPs, including 15 missense variants. In silico TFBS scanning identified 23 variants showing allele-specific gain or loss of significant motif hits, involving motifs for EBF1, CTCF, NRF1, SPI1, NFE2L2, JUN, and GFI1. We examined polymorphism in the ovine MYO16 gene region and identified candidate variants to be tested for association with productivity traits in future genotype–phenotype studies.

Ruminants doi: 10.3390/ruminants6020023

Authors: Jefferson R. Gandra Cibeli A. Pedrini Rafael H. T. B. Goes Carolina M. C. Araújo Vinicius Almeida Tiago C. Tavone Mayana P. S. Costa Kálita P. Rosa Wanderson da S. Lopes

This study evaluated the effects of forage-free diets with reduced starch levels on the productive performance, metabolism, ruminal fermentation, nutrient digestibility, and meat quality of feedlot beef cattle. Two experiments were conducted. In Experiment 1, forty uncastrated Nellore steers were distributed into 20 pens in a completely randomized design, receiving diets with increasing inclusion levels of ground corn in the total diet: C400 (400 g kg−1), C200 (200 g kg−1), C100 (100 g kg−1), and C50 (50 g kg−1), formulated without forage and based on fibrous co-products. Increasing ground corn inclusion promoted linear improvements in final body weight and average daily gain, while dry matter intake and feed efficiency showed quadratic responses. Meat quality parameters were not affected by dietary treatments. In Experiment 2, eight crossbred steers were assigned to a double 4 × 4 Latin square design and fed the same experimental diets. Higher corn inclusion increased starch and fat intake, whereas dry matter, organic matter, and protein intake showed quadratic responses. Apparent total-tract digestibility of dry matter, organic matter, and starch also followed a quadratic pattern. Ruminal fermentation parameters were affected by dietary treatments, with greater ammoniacal nitrogen concentrations at higher corn levels and quadratic responses for propionate, butyrate, and methane production. Nitrogen metabolism indicated increased urinary nitrogen and uric acid excretion with increasing dietary corn inclusion. These results demonstrate that forage-free diets based on citrus pulp and soybean hulls with different levels of ground corn can be effectively used in finishing beef cattle, improving performance without impairing meat quality while modulating ruminal fermentation and nutrient utilization.

Ruminants doi: 10.3390/ruminants6020022

Authors: Horacio Dávila Ramos Jaime Noé Sánchez Pérez Mario Alejandro Mejía Delgadillo Cristina Pérez Linares Germán Contreras López Adriana Cervantes Noriega Alberto Garfio Romero Gamaliel Molina Gámez Francisco Javier Gutiérrez Piña Juan Carlos Robles Estrada

The objective of this study was to evaluate the effects of zilpaterol hydrochloride supplementation strategies on growth performance, dietary energetics, carcass traits, and meat quality in feedlot finishing lambs. Twenty-four Dorper × Katahdin crossbred male lambs (45.5 ± 4.53 kg, mean ± SD) were used in a 27 d feeding trial. The zilpaterol supplementation strategies were: (1) control, no zilpaterol supplementation (CON); (2) zilpaterol administered once daily as a full dose in the morning feeding (ZMOR); (3) zilpaterol incorporated into the total mixed ration and continuously available throughout the day (ZMIX); and (4) intermittent zilpaterol supplementation applied in a daily alternating pattern, one day on, one day off (ZINT). A target dose of 0.20 mg/kg live weight of zilpaterol hydrochloride per administration was used for all supplemented treatments, with daily administration in ZMOR and ZMIX and alternate-day administration in ZINT. Compared to the CON, zilpaterol supplementation through the ZMOR + ZMIX strategies improved average daily gain (ADG) and feed efficiency (FE) by 28.6% and 18.5%, respectively. Additionally, dressing percentage and longissimus thoracis muscle area increased by 3.2% and 17.0%, respectively. The ZINT strategy also enhanced ADG by 20.9% and FE by 15.4%. However, ZINT did not improve hot carcass weight or dressing percentage. All zilpaterol supplementation strategies increased meat toughness by up to 39.2%. Results indicate that both the ZMOR and ZMIX strategies optimize the response to zilpaterol, with no evidence that ZMOR supplementation results in a diminished response.

Ruminants doi: 10.3390/ruminants6010021

Authors: Eduardo Michelon do Nascimento Thadeu Mariniello Silva Américo Fróes Garcez Neto Félix Barbosa Reis Élice Brunelle Lessa dos Santos Viviane Azevêdo Silva Anny Graycy Vasconcelos de Oliveira Lima Madison Willy Silva Cordeiro Roger Wagner Ana Júlia de Brito Araújo Carvalho Marcos dos Santos Lima Salete Alves de Moraes Tadeu Vinhas Voltolini Mário Adriano Ávila Queiroz Sánara Adrielle França Melo Steyce Neves Barbosa Daniel Ribeiro Menezes

Grape pomace is an agri-industrial by-product rich in fatty acids with the potential to be used in diets for goats and increase the nutraceutical properties of milk. This study aimed to investigate the effect of incorporating dehydrated grape pomace (DGP) into the diets of Saanen goats on the composition, fatty acid profile, nutritional indices of fatty acids, and antioxidant capacity of their milk. Eight multiparous Saanen goats, averaging approximately four years of age and weighing 41.2 ± 15.7 kg, were used in a double Latin square (4 × 4) design. Diets were formulated with increasing levels of grape pomace (0, 90, 150, and 210 g/kg Dry Matter—DM), replacing cactus. The data underwent analysis of variance using GLM procedure and regression analysis (both linear and quadratic) using REG procedure at a significant level of 5%. The concentration of C18:2 n-6 cis and C18:3 n-3 increased (+20.1 and +15.5%, respectively) with the grape pomace inclusion. There was a reduction in the atherogenic (−24.0%) and thrombogenic (−9.9%) indices of goat milk with the increase in DGP levels. There was a reduction in de novo fatty acids (−10.5%), Δ−9 desaturase of C14 (−21.8%) and C18 (−9.5%) indexes with the highest level of DGP. There was a quadratic effect for Ferric Reducing Antioxidant Power (FRAP) and a linear effect for phenolic compounds (PC), where the highest values were observed at the estimated levels of 160 g/kg and 210 g/kg DM, respectively. Supplementing dairy goats’ diets with dehydrated grape pomace up to 210 g/kg dry matter enhances the fatty acid profile and nutritional indices of fatty acids of Saanen goat milk without altering its basic composition. As grape production is prevalent in low rainfall regions, pomace may provide an alternative feed in areas with forage production constraints. Additionally, grape residue could establish a link between the wine and dairy sectors for cheese production, expanding markets for farmers.

Ruminants doi: 10.3390/ruminants6010020

Authors: Muralidharan Jaganadhan Thiruvenkadan Aranganoor Kannan Jayanthi Duraisamy Adel Salah Khattab Oludayo Michael Akinsola Sunday Olusola Peters

Growth traits in goats are impacted by both genetic and non-genetic variables; as such, it is critical to separate direct and maternal effects for reliable genetic assessment. This study determined the phenotypic and genetic characteristics for birth weight (BW), weaning weight (WW), and average daily gain (ADG) in Salem Black goats. The MTDFREML software was used to evaluate data from 930 kids, the progeny of 147 bucks and 804 does, gathered between 2004 and 2019. Three models were compared: Model 1 (direct genetic effects only), Model 2 (adding permanent environmental effects), and Model 3 (adding maternal genetic effects and direct–maternal covariance). The overall mean was 2.21 kg for BW, 9.23 kg for WW, and 78.27 g/day for ADG. The direct heritability estimates for BW, WW, and ADG were 0.06–0.22, 0.13–0.40, and 0.11–0.16 across models, respectively, whereas maternal heritability ranged from 0.01 to 0.13. The study revealed maternal genetic effects on birth weight but their total contribution to growth trait variation is modest, and model parsimony suggests that maternal effects on WW and ADG be excluded. Breeding programs should therefore prioritize direct selection for growth performance, whereas management strategies such as enhanced nutrition, targeted kidding, and support for first-parity do provide more rapid and effective avenues to improve pre-weaning developmental outcomes. Hence, a pragmatic approach that combines direct genetic selection and environmental optimization would result in greater genetic gain and support long-term meat production in Salem Black goats.

Ruminants doi: 10.3390/ruminants6010019

Authors: Briana VerPloeg Phillip A. Lancaster Elizabeth Walker

A multitude of factors affect the optimum calving season, requiring site-specific systems analysis. The objective of this study was to determine the effects of the calving season (S1 and S2) and the timing of calving within the season on production parameters and economics in southwest Missouri. A five-year study was conducted from 2014 to 2018 using field data recorded for 1979 Hereford cow–calf pairs. Cows were categorized by calving season and 21 d calving periods within season (Periods 1–5) in which they calved. Data were analyzed under a completely randomized design with effects of season, period, calf sex, and two and three-way interactions with the calving year as a random effect. The Cattle Value Discovery System (CVDS) beef cow model was used to estimate required cow feed and feed intake. Historical cattle market prices were used, along with total feed costs, to calculate net returns. Calving in later periods reduced the pregnancy percentage in S1 but not S2. Cows calving earlier in both seasons weaned heavier calves. Feed costs were greater in S2, but replacement heifer costs were greater in S1, especially in later calving periods. Overall, net returns were not different between S1 and S2 cows, but net returns declined in later calving periods in S1, whereas there was no difference in S2. In conclusion, at the latitude of southwest Missouri for a forage species with a bimodal growth curve, the calving period affected cow productivity and profitability in Season 1 but less so in Season 2 cows, with no difference in profitability between calving seasons.

Ruminants doi: 10.3390/ruminants6010018

Authors: Sophia Brunnbauer Ulrich Meyer Jeannette Kluess Fabian Billenkamp Christian Visscher Marlene Reich Thomas Schweder Christian Schulz Mathias Paschen Sven Dänicke Dirk von Soosten

This study evaluated the effects of four macroalgae (Colaconema spp., Ulva intestinalis, Ceramium spp., Pylaiella litoralis) and two microalgae (Haematococcus pluvialis, Porphyridium purpureum), chosen due to their local cultivability in the southern Baltic Sea region and potential gas-reducing properties reported for their taxa, on rumen fermentation and methane production. Therefore, the in vitro ANKOM Rf gas production system was used; three trials were conducted and gas kinetics, gas composition after 48 h of incubation, and short-chain fatty acids (SCFAs) were analyzed. For Trial 1.1, the algae biomasses were added at 4% to a conventional dairy diet and incubated in buffered rumen fluid for 48 h, to evaluate their potential as a supplement. In Trial 1.2, the polysaccharide-enriched algae extracts were added at 2% to the base diet using the same procedure, to investigate the role of the polysaccharide content. For Trial 2, the macroalgae biomasses were evaluated solely to assess their fermentation potential. The addition of the red alga Colaconema spp. (Colaconema) altered the SCFA profile with a shift towards propionate (rate of change in propionate concentration, ΔC3 = 1.216; p < 0.001), without compromising total SCFA yield. The same could be assessed for Ulva intestinalis (U. intestinalis), limited to Trial 2 (ΔC3 = 0.516; p < 0.001). The addition of U. intestinalis led to reduced initial gas production (p = 0.003), reaching the maximum gas production rate at 5.8 h of incubation, 0.3–0.7 h later than the others (5.1–5.5 h). While there was no significant methane reduction at the chosen inclusion rates, the results indicate that both algae influence the SCFA profile and therefore fermentation pattern, with U. intestinalis warranting further investigation on gas production dynamics.

Ruminants doi: 10.3390/ruminants6010017

Authors: Bhuwan Shrestha Rajesh Neupane Sushil Paudyal

The objective of this study was to evaluate the impact of summer calving on reproductive performance, milk yield, and culling risk in U.S. organic dairy herds. Data were obtained from the Dairy Herd Improvement records of 434 organic dairy herds across 31 states, comprising 287,927 calving records from 2018 to 2022. Calving months were categorized as winter, spring, summer, or fall. Mixed models were used to analyze the 305 d milk yield, 305 d energy-corrected milk yield, peak milk DIM, peak test-day milk yield and logistic regression, and survival analyseswere applied to analyze calving difficulty, abortion, pregnancy diagnosis, and culling outcomes. Cows calving during summer had fewer days to first service and fewer days open compared with cows calving in other seasons; however, their odds of being diagnosed as pregnant were significantly lower. Summer-calving cows produced lower 305 d milk and energy-corrected milk yields, reached peak milk production later, and had a lower peak test-day milk yield. Calving during summer was also associated with increased odds of calving difficulty and a higher risk of culling. These findings indicate that summer calving poses distinct challenges for organic dairy cows, with cumulative effects on fertility, milk production, and survivability, underscoring the need for season-specific management strategies in organic dairy systems.

Ruminants doi: 10.3390/ruminants6010016

Authors: Alessandra Crisà Marco Milanesi Giovanni Chillemi Cinzia Marchitelli

Lactation is a dynamic process characterised by a production peak at 6–8 weeks, followed by a steady decline. To understand the molecular drivers of these phases and the influence of production systems, this study aims to provide a transcriptomic characterisation of bovine milk somatic cells (BMSCs) in Holstein (HO), Simmental (SM), Simmental × Holstein crossbreed (SM × HO), and Podolica (POD) cows at 60 and 120 days in milk (DIM). Total RNA was sequenced at high coverage, and differential expression and functional enrichment analyses were performed. While a core set of milk protein and fatty acid genes was identified, breed-specific analysis showed SM × HO had the highest variation (677 differentially expressed genes, DEGs). Genes upregulated at 120 DIM involved mitochondrial metabolism and oxidative phosphorylation, while downregulated genes were associated with nuclear transcriptional regulation. At 60 DIM, SM × HO vs. HO showed 66 DEGs, with upregulated genes linked to chromatin remodelling and immune regulation. Comparing production systems, 28 DEGs between POD and HO/SM highlighted differences in mitochondrial activity and transcriptional regulation. This study bridges a knowledge gap by profiling the milk transcriptome of unexplored cattle breeds, providing novel insights into the molecular regulation of lactation.

Ruminants doi: 10.3390/ruminants6010015

Authors: Aditya Dave Di Evans Thinza Vindevoghel Michael P. Ward Anne Quain

Calf rope-and-tie is a competitive rodeo event that has drawn criticism due to concerns around the potential for stress and injury of calves. While previous studies have utilised behavioural indicators to assess the welfare of rodeo calves in the arena, there are no published studies on rodeo calf behaviour during confinement in the chute prior to release into the arena. We analysed video footage of calves in the chute prior to release during two rodeo events. The footage was categorised into short duration (SD, 28–51 s, n = 17) and long duration (LD, 52–166 s, n = 14) based on the total length of the video clip of each calf in the chute. To enable comparison, the final 28 s from both SD and LD categories before calf release were reviewed, and an ethogram was developed to assess the frequency of observable calf behaviours. All calves expressed at least one behaviour indicative of a negative mental state, with ear and head movements being the most frequent. Behaviours observed in SD and LD clips were strongly correlated (Spearman’s rank correlation coefficient 0.875, p < 0.001). Longer confinement was associated with increased frequency of “red flag” behaviours indicating fear and/or stress (chi-square = 10.48, p = 0.0149), including mouth opening, tongue protrusion, rearing and escape attempts. We conclude that calves used in roping events experience fear and stress while held in the chute, especially during longer periods of confinement.

Ruminants doi: 10.3390/ruminants6010014

Authors: Aloyce Bunyaga Rene Corner-Thomas Ina Draganova Paul Kenyon Lucy Burkitt

The behaviour of ewes within the vicinity of a natural stream and the impact on stream water quality in New Zealand hill country in summer has not been studied previously. Adult ewes (n = 40) were managed in a 1.7 ha paddock. Ewes were given access to a reticulated water trough for one week, then the trough was covered in the second week, resulting in the stream being the only source of free water available to the ewes. Ewe behaviour was monitored by video surveillance, GPS and Accelerometers. Ewes spent more time grazing and drinking within the stream zone (3 m buffer around the stream) during the restricted vs. unrestricted period (p < 0.05). Restricting water trough access had little impact on nutrient concentrations, except for ammonium-N, which increased (p < 0.05). Increased stream loads of E. coli, ammonium-N, and TP in the outflow from the paddock were evident. The spatial distribution of ewes was influenced by the slope and location of the trough and stream crossings. Ewes were least observed near the stream at night, with the highest activity in daylight. Ewes travelled greater distances as the slope increased, except at very steep slopes. While water trough access had no effect on the time ewes spent within the stream zone, there was a high density of ewe location fixes near the trough that was not seen when access was restricted. The water quality results suggest that the presence of sheep in the paddock had some impact on ammonium-N and E. coli.

Ruminants doi: 10.3390/ruminants6010013

Authors: Leilson R. Bezerra Phillip Lancaster

Ruminants continue to play a pivotal role in sustainable food production by converting abundant resources, such as rangelands, pastures, crop residues, and agro-industrial byproducts, into human-edible products of high nutritional value (meat, milk, and other dairy products) [...]

Ruminants doi: 10.3390/ruminants6010012

Authors: Saskia Marie Pawlik Nicole Wente Franziska Nankemann Doris Klocke Janina Schmidt Volker Krömker

This study aimed to evaluate recycled manure solids (RMSs) as an alternative to straw as dairy bedding under controlled in vitro conditions using two different conditioners. Pre-cut straw and RMSs were treated once with either 10 wt.% hydrated lime, 200 mL/m2 of an acidic liquid conditioner or left untreated, and incubated for three days at room temperature. Daily, samples were inoculated with manure and Klebsiella (K.) pneumoniae. Outcomes were aesculin-positive Streptococcus spp. and coliform counts, pH, and dry matter (DM) content. Hydrated lime reduced all target bacteria by >99% in both materials. The acidic conditioner decreased K. pneumoniae and streptococcal counts by 98.62%/96.6% (straw) and 98.63%/99.58% (RMSs), respectively. It reduced Escherichia (E.) coli counts by ~67% in both materials without statistical significance (p = 0.064). RMSs showed higher bacterial loads and lower DM content than straw but could be substantially improved by lime treatment. As the conditioner were applied following different manufacturer-recommended dosing principles, these findings reflect effectiveness under practical use rather than intrinsic superiority of one conditioner. RMSs might represent an alternative bedding material when managed with appropriate hygienic measures, although straw showed more favorable microbiological and physicochemical aspects. Both materials contained substantial bacterial loads prior to treatment.

Ruminants doi: 10.3390/ruminants6010011

Authors: Jorge Quintana-Zamora Verónica Andrade-Yucailla Rocio Yagual-De La Cruz Katherine Contreras-Barros Marcos Barros-Rodríguez Carlos Guishca-Cunuhay Jorge Iraola Andrés Pech-Cervantes

The aim of this research was to evaluate the effect of agro-industrial waste from C. cajan shell, plantain peels (Musa spp.), and Zea mays cob husk on in situ ruminal degradation kinetics and in vitro gas production. Rumen degradation of DM in the soluble fraction (A) was higher (p = 0.0001) in plantain peel (37.5%). The insoluble but potentially degradable fraction (B) was higher (p = 0.0001) in C. Cajan shell (71.7%). Regarding the degradation rate in percentage per hour (c: 0.13%/h), degradation potential (A + B: 86.3%) and effective degradation at the different passage rates (k) (0.02: 79.6%, 0.05: 72.4%, and 0.08: 67.3% k, respectively), it was higher (p < 0.05) in the plantain peels. Rumen NDF degradation was higher (p < 0.05) in plantain peels for all degradation parameters (A + B: 80.8, k: 0.02: 57.1%, 0.05: 44.9%, and 0.08: 37.6%, respectively). Total gas production kinetics (D; 333.3 mLgas/0.5 g degraded DM) and gas production at 24, 48, and 96 h were lower (p = 0.0001) in plantain peels. CH4 production was low (p = 0.0001) in plantain peels at all evaluated times (24 h: 32.7, 48 h: 37.9, and 96 h: 53.5 mL/0.5 g degraded DM). CO2 production was lower (p < 0.05) in C. Cajan and plantain peels at all evaluated times. Under the conditions of this study, it can be concluded that the use of plantain peels (Musa spp.) can be beneficial to animals when incorporated into the diet, as it contains a similar protein content to tropical forages, as well as low fiber content, high ruminal degradation, and secondary compounds that benefit energy maximization by mitigating enteric gas production in ruminants.

Ruminants doi: 10.3390/ruminants6010010

Authors: Hunter G. Perez Alyssa Lancaster Andrew Byron Tayla Lubinsky Sunday O. Peters Amy N. Abrams Aridany Suarez-Trujillo

Small ruminants, such as newborn lambs, rely on timely colostrum intake to acquire passive immunity through the absorption of immunoglobulin (Ig). Evaluating Ig transfer is important for ensuring lamb health and survival. However, current methods such as enzyme-linked immunosorbent assay (ELISA) and radial immunodiffusion (RID) are widely used but remain costly and require specialized facilities. The immunocrit assay has been proposed as a lower-cost alternative for evaluating serum Ig concentrations. This study aimed to evaluate the immunocrit method in lambs by comparing it with ELISA, RID, and total serum protein. Serum was collected from 135 Katahdin-Easycare lambs 24–36 h after birth. Samples were analyzed using sheep immunoglobulin G ELISA, Sheep immunoglobulin G RID, serum protein, and the immunocrit method. Pearson’s correlation was used to assess linear relationships between the methods, and Receiver Operating Characteristics (ROC) analysis was used to evaluate test accuracy, with RID as the gold standard (15 mg/mL cutoff). The immunocrit showed a high correlation with RID (r = 0.870), moderate correlation with serum protein (r = 0.725), and good correlation with ELISA (r = 0.607). The ROC analysis showed that the immunocrit had a sensitivity of 100% at a cutoff of 4.34%. These results indicate that the immunocrit method provides comparable accuracy to RID and serum protein, and could serve as a reliable, practical, and inexpensive tool for on-farm evaluation of passive transfer in Katahdin-Easycare crossbred lambs between 24 and 36 h after birth.

Ruminants doi: 10.3390/ruminants6010009

Authors: Richard Browning Jr. Emily G. Hayes Kaylee S. Hillin Maria Lenira Leite-Browning

Reduced winter hair shedding in beef cows through the spring and summer months may contribute to heat stress and reduced performance in spring-calving herds. This study evaluated the relationship of hair shedding with the fertility and maternal performance of 72 Dexter cows. Hair shedding data for 20 May, 3 June, 17 June, and 1 July in 2019 were used to classify cows as high or low hair shedders. Hair shedding levels were lower (p < 0.05) for 2-year-old cows than for cows 7+ years of age for the first three dates and lower (p ≤ 0.05) for lactating cows than for dry cows on the first two dates. Concurrent and four years of historical performance records were used to assess the associations between hair shedding and cow–calf performance. Data from 230 natural matings in July and August from 2015 to 2019 were analyzed. Birth to weaning weight data were recorded from 2016 to 2019 on 124 spring-born calves. Cow fertility was higher (p < 0.05) for high-shed cows than for low-shed cows for the 1 July classification. When the records from cows that were dry in 2019 were excluded from testing, fertility was higher (p < 0.05) for high-shed cows than for low-shed cows at all four scoring dates. The associations of cow hair shedding levels with preweaning calf performance were minimal. Dexter cows exhibiting higher hair shedding levels in the spring and summer expressed higher summer fertility.

Ruminants doi: 10.3390/ruminants6010008

Authors: Toncho Penev Elena Stancheva Gergana Bachevska Dimo Dimov Krum Nedelkov

The aim of the present study was to evaluate the association between seasonal variation, the temperature–humidity index (THI), and lipid indices related to human health in the milk of Simmental and Montbéliarde cows. The investigation was conducted on a dairy farm located in Central Southern Bulgaria over a 12-month period and included 100 lactating cows, with equal numbers from each breed, housed in semi-open free-stall barns and fed an unchanged total mixed ration. Monthly measurements of microclimatic parameters (temperature, relative humidity, THI, and air velocity) were conducted throughout the study, and composite milk samples were analyzed for fatty acid composition by gas chromatography. The atherogenic index (AI), thrombogenic index (TI), health-promoting index (HPI), hypo-/hypercholesterolemic index (h/H), desaturase indices (DI16 and DI18), and the UFA/SFA, PUFA/SFA, and MUFA/SFA ratios were calculated based on the fatty acid profile. The results indicate that season has a statistically significant effect on all studied lipid indices (p < 0.001). The Kruskal–Wallis H values ranged from 16.68 for AI to 27.82 for DI18, indicating that seasonal variations in microclimatic conditions significantly influence the lipid metabolism of the cows. The data for the studied lipid indices indicate that the most favorable fat profile for human health was observed in autumn, characterized by lower AI (2.24) and TI (1.26) values and higher HPI (0.45) and h/H (0.76) values. Seasonal variation also affected DI 16 and DI 18, with the most favorable values for humans observed in autumn (DI 16: 4.38; DI 18: 74.39). The ratios of unsaturated to saturated fatty acids (UFA/SFA, PUFA/SFA, and MUFA/SFA) indicate that the milk from the studied farm exhibits the most favorable functional properties in autumn.

Ruminants doi: 10.3390/ruminants6010007

Authors: Junior Isaac Celestin Poaty Ditengou Byungho Chae Wansun Song Inhyeok Cheon Nag-Jin Choi

Numerous studies have suggested controversial findings regarding the impact of microalgae on dairy cows’ production parameters. This meta-analysis aimed to investigate the overall effects of microalgae on dairy cows’ performance and milk fatty acids and to highlight variation factors inducing opposite findings in the impact of microalgae on dairy cow nutrition. Following the PRISMA guidelines, articles examining the influence of microalgae on dairy cows’ performance and milk fatty acids were searched through Google Scholar, Web of Science, Science Direct, and Scopus. As a result, 10 articles were selected and categorized into 18 experiments for inclusion in our meta-analysis. The results suggested significant increasing effects (p < 0.05) of microalgae on milk yield and rumenic acid, while decreasing effects (p < 0.05) were observed in caproic acid, caprylic acid, capric acid, lauric acid, pentadecanoic acid, and myristic acid. The sub-group analysis suggested that the Aurantiochytrium limacinum microalgae strain showed more consistent effects compared with other evaluated strains. Thus, the present meta-analysis makes a valuable contribution to comprehending the beneficial effect of microalgae in dairy cow nutrition and the factors that may influence the impact of this sustainable feed additive on milk production and quality.

Ruminants doi: 10.3390/ruminants6010006

Authors: Ludmila Křížová Vladimír Králik Kateřina Dadáková Petr Malý Lucie Ondrová Tomáš Kašparovský

Tannins are known for their ability to modify digestion and reduce CH4 emissions in ruminants. Novel forages able to tolerate water deficits often contain low-to-moderate levels of dietary tannins. The aim of the study was to compare the effect of tannic acid (hydrolysable tannin, HT) and Tannivin (quebracho, condensed tannins, CTs) added to a total mixed ration at a concentration of 2.5% on rumen fermentation over time using in vitro methods. The substrates were incubated with buffered rumen fluid at 39 °C for 0, 3, 6, 12, 24, and 48 h to study dry matter (DM) degradability, tannin disappearance, utilizable protein (uCP), and rumen fermentation parameters. In parallel, gas production was measured using the ANKOM-RF Gas Production System. Gas composition was determined after 24 and 48 h of incubation. DM degradability was influenced by the incubation time (p < 0.001), reaching approximately 50% after 48 h, with a similar course of degradability for both tannin types. Tannin disappearance was significantly influenced by the type of tannins and the incubation time (both p < 0.001), reaching 50% in HTs and 39% in CTs within the first 6 h of fermentation. Production of individual and total VFA and uCP increased during incubation (p < 0.001) but were not influenced by the tannin type. However, the formation of uCP was relatively stable over time. Ammonia-N production increased during the first 12 h of fermentation with both tannin types and the increase continued with HTs (p < 0.001). Gas and methane production increased during fermentation and the increase was more substantial in HTs (p < 0.001). Our results suggest that at moderate concentrations, tannins mainly affect protein metabolism, with a minor effect on rumen fermentation.

Ruminants doi: 10.3390/ruminants6010005

Authors: Jesus Nuñez Felimon Paxi-Meneses Wilder Cruz Richard Estrada

Livestock production in the high Andes is vital for rural livelihoods and food security but is limited by poor pasture quality, environmental variability, and restricted resources. Pasture improvement, achieved through management practices and particularly through fertilization, may enhance productivity and sustainability in high-Andean livestock systems. This study aimed to characterize mixed herds composed of domestic sheep (Ovis aries), alpacas (Vicugna pacos), llamas (Lama glama), and domestic cattle (Bos taurus) and to evaluate the role of pasture fertilization on herd composition and livestock size. Primary data were collected through structured questionnaires administered to 88 randomly selected livestock producers, complemented by direct field observations of grazing areas, corrals, shelters, and water sources. The survey documented herd structure, grazing management, pasture conservation, fertilization practices, and farm infrastructure. Data from multiple farms were analyzed using a clustering approach to group production units with similar characteristics, and statistical models were applied to assess the effects of fertilization, pasture area, and water sources. Three distinct clusters were identified: one dominated by alpacas, another by sheep, and a third by llamas with the most uniform stocking density. Pasture fertilization was most common in the sheep-dominated cluster and was significantly associated with higher sheep numbers, while no significant effects were detected for alpacas, llamas, or cattle. Farms without fertilization showed slightly higher overall livestock size; however, a strong negative interaction between pasture area and lack of fertilization indicated that expanding grazing land alone could not offset low forage quality. These findings suggest that targeted fertilization, when combined with sustainable grazing practices, may contribute to improved herd performance and long-term resilience in heterogeneous Andean livestock systems.

Ruminants doi: 10.3390/ruminants6010004

Authors: Iran A. Torquato Meirielly Jesus Fernando Mata Joana Santos Hortência E. P. Santana Júlia M. S. C. Guimarães Cleber T. F. Costa Daniel P. Silva Denise S. Ruzene

Prolonged drought and resource scarcity have limited feed availability for livestock in arid and semi-arid regions, necessitating strategic resource management to sustain cattle productivity. This study evaluated the use of spineless cactus as an alternative feed ingredient for ruminants in dryland areas. The experiment assessed in vitro cumulative gas production from silages of Miúda forage cactus (Nopalea cochenillifera Salm-Dyck) combined with Tifton 85 Bermuda Grass (Cynodon sp.) hay and varying levels of urea (1%, 2%, and 3% on a dry matter basis) as a nitrogen source. Traditional supplements comprising Tifton hay, wheat bran, soybean meal, and urea served as controls. Kinetic organic matter degradation parameters exceeded 60%. Dry matter degradability was similar across all urea levels at six hours but diverged over time, with the 3% urea treatment showing lower degradability at 48 and 96 h. Organic matter degradability varied throughout incubation, with the 2% urea treatment performing best. Overall, these findings suggest that silage made from native Miúda forage cactus combined with Tifton hay and up to 2% urea can serve as an effective alternative roughage to meet the nutritional requirements of ruminants, particularly during periods of feed scarcity in arid environments.

Ruminants doi: 10.3390/ruminants6010003

Authors: Maria P. Nikolopoulou Athanasios I. Gelasakis Konstantinos Demestichas Aphrodite I. Kalogianni Iliana Papada Paraskevas Athanasios Lamprou Antonios Chalkos Efstratios Manavis Thomas Bartzanas

Precision livestock farming (PLF), by integrating multimodal sensor data, provides opportunities to enhance welfare monitoring and management in small ruminants. This study evaluated whether environmental, physiological, and behavioral measurements—including the temperature–humidity index (THI), carbon dioxide (CO2) and ammonia (NH3) concentrations measured at the barn level, body condition score (BCS), rectal and ocular temperatures, GPS-derived locomotion metrics, accelerometry data, and fixed animal traits—can serve as key predictors of welfare and productivity in dairy sheep. Data were collected from 90 ewes: all animals underwent the same repeated welfare assessments, while 30 of them were additionally equipped with GPS–accelerometer sensor collars; environmental conditions were continuously recorded for the entire flock, generating 773 complete multimodal records. All predictive models were developed using data from all 90 ewes; collar-derived behavioral variables were included only for individuals equipped with GPS–accelerometer collars. Nine regression methods (linear regression (LR), partial least square regression (PLSR), elastic net (EN), mixed-effects models, random forest (RF), extreme gradient boosting (XGBoost), support vector regression (SVR), neural networks (multilayer perceptron, MLP), and an ensemble of RF–XGBoost–EN were evaluated using a combination of nested cross-validation (CV) and leave-one-animal-out CV (LOAOCV) to ensure robustness and generalization at the individual animal level. Nonlinear models—particularly RF, XGBoost, SVR, and the ensemble—consistently delivered superior performance across traits. For behavioral (e.g., daily distance movement) and thermal indicators (e.g., medial canthus temperature), the highest predictive capacity (R2 ≈ 0.60–0.70) was achieved, while moderate predictive capacity (R2 ≈ 0.40–0.50 and ≈0.35–0.45), respectively, was observed for respiratory rate and milk yield, reflecting their multifactorial nature. Feature importance analyses underscored the relevance of THI, CO2, NH3, concentrations, and BCS across results. Overall, these findings demonstrate that multimodal sensor fusion can effectively support the prediction of welfare and productivity indicators in intensively reared dairy sheep and emphasize the need for larger and more diverse datasets to further enhance model generalizability and model transferability.

Ruminants doi: 10.3390/ruminants6010002

Authors: Mirelle Magalhães Souza Julián Andrés Castillo Vargas Andressa Moraes Carvalho Ana Carolina Müller Conti Daniel Henrique Souza Tavares Bárbara Pércya Lopes Coelho Eduardo Pereira Santos José Neuman Miranda Neiva Fabrícia Rocha Chaves Miotto

The aim of this study was to evaluate the effects of oregano essential oil (OEO) as a replacement for monensin (MON) on performance, carcass characteristics and meat quality in heifers finished either in confinement or on pasture. Thirty-six Nellore heifers (252.44 kg ± 21.80 kg) were distributed in a completely randomised design in a 2 × 2 factorial scheme, with two types of additives and two finishing systems. In both systems, a concentrate at 1.5% of body weight (BW) on a dry matter (DM) basis containing MON (282.2 mg/animal/day) or OEO (300 mg/animal/day) was offered daily. The final BW (FBW) and average daily gain (ADG) were higher in confinement-finished animals than in those finished on pasture (p < 0.01). There was no effect from the finishing system (p ≥ 0.376) or additive (p ≥ 0.057) for hot-carcass weight, hot-carcass yield, subcutaneous fat thickness, or the Longissimus lumborum area. The pH and shear force of the meat did not differ between treatments (p ≥ 0.076). Finishing in confinement resulted in brighter meat than finishing on pasture (p ≤ 0.006). The use of OEO increased the redness of the meat (p ≤ 0.042). Consumer perception (n = 63) of the sensory attributes of aroma, colour, tenderness, flavour and juiciness was not affected by the treatments (p > 0.05). Heifers finished in confinement or on pasture, with the same proportion of concentrate in the diet and the addition of MON or OEO, presented similar characteristics for both the carcass and the meat.

Ruminants doi: 10.3390/ruminants6010001

Authors: Abdelmuhsen Al Alami Antonio Gimeno Sofía Schauf Carlos Castrillo Antonio de Vega

Barley is more extensively and more rapidly fermentable than maize, thus it is supposed to increase digestive disorders in ruminants. However, the effect of cereal type on animal performance and digestion may vary with processing degree. In the present experiment, the effect of dry-rolling or grinding barley and maize, as the main cereals in a concentrate containing a high proportion of starch with different rates of fermentation, on intensively reared beef cattle performance, diet digestibility, and feed intake amount and pattern, was studied. Thirty-six 3-month-old male calves were allocated to one of four diets consisting of barley straw (BS) and a concentrate with 60% cereals (barley and maize in proportions 75:25 or 25:75) presented dry-rolled or ground through a 3.5 mm sieve. The experimental period was divided into two phases of 10 weeks each: from start to 277 ± 3.6 kg live weight (LW; Growing), and from 289 ± 3.8 kg LW to slaughter (399 ± 4.6 kg; Finishing). For the Growing phase, there were no differences (p > 0.10) between the majority cereal in the concentrates, nor between their processing methods, in the daily intake of concentrate and BS, and in the animals’ final LW. With respect to Finishing, the interaction between cereal type and processing was significant (p < 0.05) for concentrate daily intake. As a result, animals consuming ground barley ate less concentrate than those fed rolled barley, whereas there were no differences between processing methods for animals fed maize-based diets. Animals consuming ground-barley concentrates consumed significantly more straw than those fed on dry-rolled-barley concentrates (p < 0.05 for Growing and p < 0.01 for Finishing) during the first four hours after feeding. No such differences appeared in animals consuming maize-based concentrates. Starch digestibility was higher in animals fed ground cereals vs. dry-rolled cereals during the Growing phase (p = 0.048), whereas NDF digestibility was also higher (p = 0.008) in animals fed ground cereals during the Finishing phase. The faeces from animals fed on rolled-maize concentrates showed a higher concentration of purine bases than the faeces of animals fed on rolled-barley concentrates (p = 0.016), although there were no differences for the ground cereals. Overall, the results reported indicated that replacing maize with barley in diets for feedlot beef cattle did not affect average daily gain, intake of straw or concentrate, or feed conversion ratios (total or considering just the concentrate); hence the inclusion of either cereal in greater proportions should be based on their market price and on the final cost of the compound feed (which may include different ingredients). The processing method of the cereals (grinding or dry-rolling) also had no influence on the above-mentioned variables, so the selection of the method should be based on their relative cost, exclusively in terms of feed efficiency.

Ruminants doi: 10.3390/ruminants5040064

Authors: Jozivaldo Prudêncio Gomes de Morais Adibe Luiz Abdalla Alexandre de Azevedo Olival Mariana Campana Francine Basso Facco Tiago Antonio Del Valle

Edible trees, such as Bordão-de-velho (BVP; Samanea tubulosa), are being studied for their nutritional potential and the presence of bioactive compounds that influence ruminal fermentation. This study aimed to evaluate, using an in vitro assay, the effects of increasing the inclusion of BVP pods in dairy cow diets formulated with different energy levels. The experiment was conducted with eight treatments obtained from a 4 × 2 factorial arrangement, containing four levels of pod inclusion (0, 100, 200, and 300 g/kg dry matter) and two dietary energy levels (high and low). Increasing BVP levels resulted in a linear reduction in gas production from digestible organic matter in low-energy diets, without altering dry matter and organic matter digestibility or methane production. There was an increase in pH and in the acetate/propionate ratio, along with a reduction in the concentrations of short-chain fatty acids and isoacids. In conclusion, Samanea tubulosa pods improve fermentation efficiency and reduce gas production, making them a promising forage source for low-productivity animal diets.

Ruminants doi: 10.3390/ruminants5040063

Authors: Jorge A. Maldonado-Jáquez Glafiro Torres-Hernández Gabriela Castillo-Hernández Lino De La Cruz-Colín Gerardo Jiménez-Penago Sandra González-Luna Liliana Aguilar Marcelino Pablo Arenas-Báez Lorenzo Danilo Granados-Rivera

This narrative review aims to summarize, synthesize, and organize current knowledge on the adaptation of sheep and goats to stressful environments and to discuss how these adaptations contribute to food security in vulnerable communities. A structured search of Web of Science, Scopus, PubMed, and Google Scholar was conducted using combinations of terms related to sheep and goats, harsh environments (e.g., arid and semi-arid regions, heat stress, water restriction, poor-quality forage), and adaptation or resilience, combined with Boolean operators. A total of 1718 research publications were found, of which 86 were retained as the most relevant because they provided direct and detailed evidence on anatomical, physiological, digestive–microbiome, behavioral, and genomic adaptations of sheep and goats to stressful environments. The selected studies describe a wide range of phenotypic and integumentary traits, thermoregulatory and endocrine responses, digestive and microbial adjustments, behavioral strategies, and genomic signatures that, together, allow small ruminants to maintain basic functions, reproduction, and production under conditions of climatic and nutritional stress. Evidence from these studies also highlights how adaptive traits support herd productivity, economic stability of households, and the sustainable use of natural resources in regions where climatic variability and resource scarcity are common. Overall, the synthesis presented here underscores the importance of conserving and strategically using locally adapted sheep and goat breeds, incorporating resilience-related traits into breeding and management programs, and prioritizing further research on genomic, microbiome, and epigenetic mechanisms that underpin adaptation to harsh environments.

Ruminants doi: 10.3390/ruminants5040062

Authors: Anghy Ruiz-Salazar Erika Pavez-Muñoz Juan Pablo Keim Michael M. Fry Carolina Ríos Pilar Sepúlveda-Varas Ricardo H. Chihuailaf

The aim of this study was to evaluate the relationship between cows’ hepatic lipid content (HLC) at 10 days in milk (DIM) and their metabolic status, health, and production during transition and early lactation periods. HLC was determined in 103 cows from a grazing Chilean dairy herd via cytologic examination of the liver through fine needle biopsies, categorized as mild, moderate, or severe. Blood metabolites were evaluated in the transition period, together with diseases in the postpartum period and milk production during the first 90 DIM. In pre-partum and postpartum periods, primiparous cows with severe HLC showed higher plasma cholesterol than multiparous cows with mild HLC. Postpartum, cows with severe HLC had higher serum non-esterified fatty acids (NEFAs) and NEFA/cholesterol ratios than those with mild HLC. Similarly, cows with moderate and severe HLC presented higher plasma β-hydroxybutyrate and greater risk of subclinical ketosis than cows with mild HLC. Additionally, cows with severe HLC had higher milk production and lower milk protein content than those with mild HLC. These results indicate that moderate to severe HLC at 10 DIM was associated with negative energy balance and subclinical ketosis, whereas severe HLC was associated with increased milk production and decreased milk protein content.

Ruminants doi: 10.3390/ruminants5040061

Authors: Andreza Malena Guedes da Costa Silva Héliton Pandorfi Weslley Amaro da Silva Alex Souza Moraes Hilton José de Lima Pereira Gledson Luiz Pontes de Almeida Nítalo André Farias Machado Maria Beatriz Ferreira Marcos Vinícius da Silva

The present study aimed to apply machine learning algorithms to estimate respiratory rate (RR, breaths min−1) and rectal temperature (RT, °C) as indicators of thermal stress in Dorper breeding rams, based on environmental and thermal variables obtained through infrared thermography. The algorithms Random Forest (RF) and Support Vector Regression (SVR) with radial kernel were employed, using ocular globe temperature (OGT), air temperature (AT), relative humidity (RH), and coat surface temperature (CST) as predictor variables, and rectal temperature (RT) and respiratory rate (RR) as response variables. Data were collected on a property located in Garanhuns, Pernambuco State, Brazil, under two environmental conditions (with and without climate control), totaling 20 monitored animals and 120 paired observations. Model performance was evaluated using the coefficient of determination (R2), Root Mean Squared Error (RMSE), and Mean Absolute Error (MAE), complemented by cross-validation (k-fold = 10), and model interpretability was assessed using SHapley Additive exPlanations (SHAP) to quantify the contribution of each predictor variable to model predictions. The results indicated that the RF model showed superior performance in predicting the physiological variables RR and RT, with higher coefficients (RR: R2 = 0.858; RT: R2 = 0.687) and lower error values. For RR, the RF model achieved RMSE = 16.38 and MAE = 13.33; while for RT, the errors were RMSE = 0.217 and MAE = 0.154. In contrast, the radial kernel SVR model showed lower performance, with R2 values of 0.742 (RR) and 0.533 (RT), and RMSE and MAE values of 21.05 and 17.38 for RR, and 0.262 and 0.196 for RT, respectively. The application of machine learning-based models proved to be a viable and accurate alternative for estimating physiological indicators of thermal stress, contributing to the development of automated thermal management strategies for sheep in the Brazilian semi-arid region. The proposed data-driven approach demonstrates that low-cost thermal sensors combined with explainable artificial intelligence can support automatic decision-making for climate adaptation and animal welfare in semi-arid sheep production systems.

Ruminants doi: 10.3390/ruminants5040060

Authors: Ebtissem Brahmi Loredana Basiricò Mohammad Ataallahi Umberto Bernabucci Rachid Bouraoui

Background: Cortisol is known as the main hormone released during stress responses in cattle and has been used to assess various stressors, including heat stress. This study investigated hair cortisol concentration (HCC) in different hair coat colors in dairy cows under natural heat stress conditions (temperature humidity index = 75). Methods: Hair samples were collected from the forehead region of ten multiparous cows (Brown Swiss, Montbéliarde, and Holstein) per group color at both the beginning and end of a three-week peak summer period in 2024 in the region of Jendouba, North Tunisia. Cows were grouped according to hair coat color (black, brown, red, white, and yellow) for subsequent analysis. Hair samples were prepared using a methanol-based separation protocol and analyzed via enzyme-linked immunosorbent assay (ELISA). Results: Meteorological data confirmed that cows were sustained under heat stress, with an average temperature humidity index value of 75; results indicated that black hair had considerably more HCC than white hair (p < 0.05). The results showed that there is a significant difference between HCC under three clusters (p < 0.05) according to hair color. Conclusions: The study emphasizes that hair color, along with factors such as breed and environmental conditions, should be carefully considered when using HCC to assess stress in cattle beyond simply black or white hair color.

Ruminants doi: 10.3390/ruminants5040059

Authors: Alvimara Felix dos Reis Paulo Sávio Lopes Renata Veroneze Eula Regina Carrara Marco Antônio Sundfeld da Gama Frank Angelo Tomita Bruneli Fernando César Ferraz Lopes Aníbal Eugênio Vercesi Filho Maria Raquel Santos Carvalho Pablo Augusto de Souza Fonseca Maria Gabriela Campolina Diniz Peixoto

Studies in taurine breeds have shown that genetic selection can improve the fatty acid (FA) profile of bovine milk, but studies are scarce considering Zebu animals. In this study, genetic parameters for FA concentrations and unsaturation indexes in the milk fat of Zebu cows were estimated, with emphasis on Gir and Guzerá breeds. Milk samples from 299 Gir and 266 Guzerá cows belonging to 22 herds distributed throughout Brazil were analyzed using gas chromatography. Fourteen individual FAs, 11 FA groups, four nutritional indexes, and five unsaturation indexes were evaluated. Tri-trait Bayesian models were applied, including 305-day milk and fat yields as “anchor” traits. Systematic effects such as contemporary group, age at calving, diet, sampling age class, and days in milk were considered. Palmitic acid was the most abundant FA, followed by oleic, stearic, and myristic acids. Heritability estimates ranged from moderate to high: 0.28–0.66 in Gir cows, and 0.25–0.74 in Guzerá cows, for individual FAs and FA groups. Unsaturation indexes also showed moderate to high heritability. Genetic correlations were generally strong, with long-chain FAs negatively correlated with short- and medium-chain FAs. The results suggest that genetic selection can be applied to improve the nutritional profile of milk fat in Zebu cattle.

Ruminants doi: 10.3390/ruminants5040057

Authors: Kiro Risto Petrovski Roy Neville Kirkwood Saulo Teixeira Rodrigues de Almeida Mariana Caetano

Despite the critical importance of nutritional assessment in veterinary medicine, internationally recognized guidelines for compromised ruminants remain absent. This paper addresses this significant gap by presenting comprehensive nutritional assessment protocols adapted from small animal and equine guidelines, combined with clinical experience and ruminant-specific considerations. Therefore, the objective of this article is to establish standardized nutritional assessment guidelines for compromised ruminants that facilitate early detection of risk factors and nutritional imbalances affecting animal welfare and productivity, while guiding appropriate clinical nutritional interventions. The guidelines integrate systematic screening and extended evaluation protocols encompassing patient signalment, comprehensive health interviews, environmental examination, and nutrition-focused clinical assessments. The framework incorporates validated scoring systems including body condition scoring, fecal consistency and digestibility scores, rumen fill assessment, and muscle scoring. Laboratory evaluations including blood biochemistry, hematology, milk quality records, and metabolite profiling support clinical decision-making. The proposed assessment framework addresses animal-specific factors, diet-related considerations, feeding management practices, and environmental influences on nutritional status. Critical evaluation points include alimentary system function and integrity, forestomach assessment, and detection of malabsorption syndromes. The guidelines emphasize that many nutritional abnormalities manifest non-specifically, and detection limitations exist, particularly in peracute presentations. In conclusion, successful clinical nutritional interventions require comprehensive assessment protocols that prioritize rumen health maintenance and oral diet delivery whenever possible. The guidelines we suggest will provide veterinary and nutritional practitioners with systematic tools for evaluating compromised ruminants, establishing appropriate interventions, and monitoring outcomes using SMART goals. Further research is warranted to refine specific dietary requirements for compromised ruminants and validate intervention protocols across diverse production systems.

Ruminants doi: 10.3390/ruminants5040058

Authors: Janayna Barroso dos Santos Felipe Masiero Salvarani

Climate change poses significant challenges to livestock, particularly in tropical regions. The Amazon biome, which hosts one of the world’s largest cattle populations, faces growing risks of nutritional, metabolic, and infectious diseases driven by heat stress (HS) and environmental instability. This systematic review synthesizes evidence from primary studies, international reports (IPCC, FAO), and peer-reviewed literature on cattle physiology, disease dynamics, and climate adaptation. HS reduces feed intake, disrupts endocrine–metabolic homeostasis, and suppresses immunity, increasing susceptibility to metabolic, deficiency and infectious diseases. Breed-specific immune responses offer opportunities for genetic and management-based adaptation. Socio-economic impacts disproportionately affect smallholders, linking livestock health to food security and poverty. Ensuring sustainable cattle production in the Amazon will require climate-smart strategies integrating nutrition, genetics, reproduction, and health management, supported by policies that align adaptation and mitigation. Future research should prioritize immune-metabolic biomarkers, periparturient disease monitoring, and genomic tools for thermotolerance.

Ruminants doi: 10.3390/ruminants5040056

Authors: Bukeka Mtenjwa Olusegun Oyebade Ikusika Conference Thando Mpendulo

The present study determined the effects of varying inclusion levels of baobab oilseed cake (BOSC) combined with fossil shell flour (FSF) diets on body condition scores, body weight gain, and nutritionally related blood metabolites of Angora goats. Twenty-four Angora goat wethers aged 5–6 months, weighing 12.75 ± 1.5 kg, were kept in individual pens for 105 days of successive feeding, including a 14-day adaptation period. Goats were randomly allocated to four dietary treatments: 0%, 5%, 10%, and 15% BOSC (n = 6). Each goat was offered experimental diets at 4% of its body weight daily at 08:00. Goats were then released to graze on natural pastures at 10:00 and returned to their respective pens at 16:00 daily. Body weight gain, body condition scores, and blood concentrations were determined. Angora wethers BCS linearly increased (p < 0.05) as weeks progressed in all inclusion levels of BOSC. Body weight gain increased linearly (p < 0.05) in goats fed 0% and 10% BOSC across the 13-week feeding period, while goats fed 5% BOSC showed a sharp quadratic increase (p < 0.05) between weeks 5–6 and those fed 15% BOSC between weeks 3–8. Creatinine levels showed a sharp quadratic decline (p < 0.05) between 10–15% BOSC inclusion, while urea levels quadratically declined (p < 0.05) between 0–5% inclusion. Phosphorus concentrations also decreased quadratically (p < 0.05), reaching their lowest values between 5% and 10% BOSC, while total protein, glucose, magnesium, albumin, and calcium remained unchanged (p > 0.05) across dietary treatments. In conclusion, this preliminary study suggests that the inclusion of 15% BOSC improves BWG, BCS, and nutritionally associated blood metabolites in Angora goats. Further studies with a larger number of animals are recommended to confirm these findings.

Ruminants doi: 10.3390/ruminants5040055

Authors: Ulises Macías-Cruz Karen M. Valadez-García María de los Ángeles López-Baca Leonel Avendaño-Reyes Ricardo Vicente-Pérez Miguel Mellado César A. Meza-Herrera José A. Roque-Jiménez Raúl Díaz-Molina Pablo Luna-Nevárez

Oxidative stress impairs the productivity and welfare of heat-stressed hair sheep; however, the key factors contributing to its occurrence remain unclear. Twenty-two Dorper × Katahdin ewe lambs weighing 23.5 ± 2.8 kg and experiencing outdoor heat stress in a desert region were used to establish the contribution of climatic variables, physiological responses, metabolism, and feedlot performance to the oxidant-antioxidant imbalance. Pearson’s correlation, principal component analysis, and multiple linear regression were applied to the datasets. Oxidative stress biomarkers showed positive relationships with average and minimum climatic variables, morning rectal temperature, serum triglycerides and insulin, and feed efficiency. Still, these biomarkers were negatively correlated with maximum ambient temperature (Te) and temperature-humidity index (THI), morning and afternoon respiratory rate (RR), total protein, and feed intake. While total oxidant capacity and fat oxidation were mainly associated with decreased maximum Te, protein oxidation was primarily associated with increased morning RR. Total antioxidant capacity was favored by a reduction in maximum THI and oxidative stress index (OSI) by an increase in maximum relative humidity. With minimal contribution (≤6%), protein and fat oxidation were also explained by increased serum insulin and feed intake, respectively, whereas OSI was explained by increased weight gain. Overall, the presence of oxidative stress in feedlot hair sheep experiencing outdoor heat stress was regulated by a combination of climatic conditions, morning RR, and, to a lesser extent, productive performance.

Ruminants doi: 10.3390/ruminants5040054

Authors: Roberto Germano Costa Talma Jordana Lima Ariosvaldo Nunes Medeiros José Teodorico de Araújo Filho Neila Lidiany Ribeiro Geovergue Rodrigues Medeiros Tairon Pannunzio Dias-Silva Francisco Fernando Ramos de Carvalho

Spineless cactus, known for its high heat tolerance and low water requirements, offers a sustainable alternative for animal feed in regions where conventional crops struggle to thrive. This study aimed to evaluate the carcass characteristics, leg tissue composition, and non-carcass constituents of lambs fed increasing levels (0, 15, 30, and 45% based on dry matter) of spineless cactus as a replacement for Tifton hay. Additionally, we estimated body weight and carcass traits using biometric measurements (BM). Forty male lambs, with an average initial body weight of 23.6 ± 2.58 kg, were subjected to a feedlot regime. Empty body weight was the only variable that showed a significant orthogonal contrast between the control group (0%) and those fed spineless cactus (p < 0.05). A quadratic regression effect (p < 0.05) was observed for the weights of the cold half carcass, neck, shoulder, and leg cuts. No significant effects were found on non-carcass components or biometric measurements. Biometric measurements showed strong positive correlations with slaughter weight and carcass characteristics. Based on these findings, replacing 30% of Tifton hay with spineless cactus is recommended as the optimal level, as it maintains carcass quality, tissue composition, and non-carcass traits. Moreover, biometric measurements prove to be effective tools for predicting slaughter weight and carcass characteristics, offering practical value for farmers seeking efficient and sustainable production strategies. The inclusion levels of 24.25% to 27.50% of spineless cactus in the diet of confined sheep appear to be the most efficient, promoting high-value commercial cuts without compromising carcass quality parameters. These levels balance productive performance and sustainability, especially in semi-arid regions.

Ruminants doi: 10.3390/ruminants5040053

Authors: Anastasia Frantzola Apostolos Ntairis George P. Laliotis

Individual vocal recognition is essential for social cohesion and survival among conspecifics. In sheep, it facilitates postnatal identification and strengthens the mother–offspring bond. Although vocal individuality has been well-documented in lambs and ewes, little is known about whether rams—typically reared separately in farming systems—exhibit acoustic distinctiveness. This study investigated whether rams express vocal individuality across different emotional contexts and whether their calls convey contextual information. Adult rams’ vocalizations were recorded across five emotionally distinct contexts: physical and visual isolation (morning and evening), auditory exposure to ewes’ bells without visual contact, feed anticipation, and feed denial. Implementing discriminant function analyses and linear mixed models, we assessed individual distinctiveness and contextual variation in acoustic parameters. Rams exhibited vocal individuality ranging from 59% to 80%, with higher distinctiveness in negative contexts compared to positive ones. Vocal distinctiveness persisted across contexts, albeit to a lesser degree, suggesting some degree of acoustic stability. Calls were classified above chance by context, suggesting rams use vocalizations to convey affective states. Formant dispersion and amplitude variation were the most informative raw acoustic parameters under negative from positive contexts. The findings indicate that rams exhibit context-dependent vocal individuality, potentially conveying affective states through vocalizations.

Ruminants doi: 10.3390/ruminants5040052

Authors: Ronaildo Fabino Neto Marinaldo Divino Ribeiro Cássio José da Silva Sérgio Lúcio Salomon Cabral Filho Rodrigo Vidal Oliveira Mônica Maria de Almeida Brainer Ozana de Fátima Zacaroni José Mauro da Silva Diogo Emmanuel Arnhold Ramon Souza Oliveira Rogério Bernardo Cardoso Douglas Messias Lamounier Camargos Rezende Flávia Oliveira Abrão Pessoa

Improving livestock nutrition with natural supplements can enhance productivity and meat quality. This study evaluated whether a clayey micromineral compound (CMC) in lamb diets improves feed efficiency, health, and meat traits. Twenty-four 60-day-old Dorper/Santa Inês crossbred lambs (28.41 ± 4.147 kg initial weight) were randomly assigned to four CMC doses (0%, 0.4%, 0.8%, or 1.2% of dry matter intake/day) for 90 days, following a 15-day adaptation. The lambs were individually housed, with daily feed intake monitoring, weekly weight measurements, and blood analyses at the start and end. On day 89, rumen fluid was sampled for digestion analysis, and post-mortem evaluations were used to assess meat quality and rumen health. The results showed that 0.8% CMC optimized fat and fiber digestion (p < 0.05), while higher doses linearly improved meat color intensity (p < 0.05). Blood tests indicated better liver function at intermediate doses (p < 0.05). However, the CMC did not affect overall growth, feed intake, or carcass traits. The supplement was safe but provided selective benefits. These findings suggest that CMCs could enhance feed efficiency and meat appeal, although further research is needed to refine dosing for maximum impact.

Ruminants doi: 10.3390/ruminants5040051

Authors: Saulo Teixeira Rodrigues de Almeida Mariana Caetano Roy Neville Kirkwood Kiro Risto Petrovski

A significant gap in specific nutritional guidelines for ruminants with compromised health exists. Due to their unique anatomy, physiology, and metabolic processes, further research is needed to establish accurate, evidence-based recommendations tailored to these animals. This review highlights the critical role of clinical ruminant nutrition and provides provisional recommendations based on studies in other species (e.g., changes in nutrient requirements in different morbidities available for humans and less for companion animals). These suggestions should be interpreted cautiously until more definitive, species-specific data become available. The review includes the foundational principles of clinical nutrition in ruminants, with particular emphasis on the pathophysiology of nutrient utilization. It explores the roles of energy, protein, vitamins, and minerals during illness or injury and discusses how these nutrients can be strategically applied in clinical interventions. Considerations for designing diets for compromised ruminants are also addressed, considering both physiological needs and the challenges posed by illness and injury states. Practical aspects of diet delivery during treatment are examined, including the indications, benefits, limitations, and potential side effects of route of feeding. Clinical nutrition can be administered orally, enterally (including rumen delivery) or parenteral, depending on the localization of the pathology and the integrity of the alimentary tract. Nutrients should be provided based on livestock requirements and pathophysiology and severity of the primary morbidity. Oral or ruminal provision of diet should be prioritized to maintain rumen functionality. Additionally, a list of pharmaconutrients with potential clinical applications in ruminant medicine is presented to encourage future research and integration into veterinary practice. The success of clinical nutritional interventions can be measured by improvements in appetite, behavior, and health of the compromised ruminant.

Ruminants doi: 10.3390/ruminants5040050

Authors: Leilson R. Bezerra Pedro H. S. Mazza Kevily H. de O. S. de Lucena Maria Andrea F. Amorim José Fabio P. de Moura Juliana Paula F. de Oliveira Ronaldo L. Oliveira Analívia M. Barbosa Mozart A. Fonseca José Morais Pereira Filho

Urea is one of the most widely used sources of non-protein nitrogen (NPN) in ruminant diets due to its low cost and high availability. However, its rapid solubilization in the rumen can result in abrupt ammonia release, leading to toxicity risks and low nitrogen utilization efficiency. In this context, slow-release technologies, particularly microencapsulation, have been developed to synchronize NPN release with fermentable carbohydrate availability, thereby enhancing microbial protein synthesis, improving animal performance, and reducing environmental impacts. This review compiles recent advances in urea microencapsulation, emphasizing different wall materials such as waxes, lipids, polysaccharides, and fatty acids, as well as drying techniques and formulation strategies. Slow-release urea (SRU) addition in small ruminants’ diet may increase nutrient intake and digestibility, improve N balance, and reduce urinary excretion losses. Regarding performance, positive responses are observed when nitrogen release is properly synchronized with energy availability, although the results may vary depending on the encapsulant type, forage-to-concentrate ratio, and ruminal passage rate. Additionally, effects on meat quality and environmental parameters indicate that this technology holds not only zootechnical but also socio-environmental potential. It is concluded that urea microencapsulation can represent a promising alternative to optimize NPN use efficiency in ruminant production systems, though greater methodological standardization, long-term evaluations, and comparative economic analyses are required to encourage its broader adoption.

Ruminants doi: 10.3390/ruminants5040049

Authors: Paulo D. Carvalho Vanda G. Santos Stergios Priskas Emanuel Carreira Jose A. L. Castro Pablo J. Ross Georgios Arsenos

The objective of this study was to develop a stochastic simulation model to evaluate the impact of accelerated lambing on income over feed cost (IOFC) in Lacaune ewes managed under an intensive production system in Greece. The economic comparison of two lambing intervals (LI) was performed by varying the voluntary waiting period to allow for an 8-month LI (3 lambings in 2 years) versus a 12-month LI (1 lambing per year). Milk production per year was greater (p < 0.01) for the 8-month compared to the 12-month LI (777.4 ± 2.8 kg vs. 661.9 ± 2.1 kg, respectively), and the income from the sale of milk was greater for the 8-month compared to the 12-month LI (EUR 1166.0 ± 4.1 vs. EUR 992.9 ± 3.1, respectively). Feed cost per year was greater for the 8-month compared to the 12-month LI (EUR 255.9 ± 0.5 vs. EUR 227.8 ± 0.5, respectively). Therefore, IOFC per year was greater for the 8-month compared to the 12-month LI (EUR 989.4 ± 3.2 vs. EUR 817.1 ± 2.1, respectively). The cost per additional day open in the 12-month LI was estimated at EUR 1.08 ± 0.06 and demonstrates the importance of reproductive performance in the profitability of dairy sheep production. Therefore, reproductive management strategies that result in reduced LI are expected to increase IOFC in Lacaune dairy ewes. Future research is needed to develop practical strategies to successfully reduce the lambing interval in Lacaune ewes.

Ruminants doi: 10.3390/ruminants5040048

Authors: Geraldo Moreira Silva Filho Jordania Oliveira Silva Audisio Alves Costa Filho Roberta Nunes Parentoni Arthur Willian Lima Brasil Thais Ferreira Feitosa Vinícius Longo Ribeiro Vilela

We aimed to assess the seroprevalence of anti-Neospora caninum and anti-Toxoplasma gondii antibodies in cattle intended for human consumption in Paraíba, Brazil, and the associated risk factors. A total of 110 serum samples from slaughtered cattle were analyzed using the Indirect Fluorescence Antibody Test (IFAT), with cut-off points of 1:200 for N. caninum and 1:64 for T. gondii. Seroprevalence was 8.2% (9/110) for N. caninum (titers 1:200–1:6400) and 18.2% (20/110) for T. gondii (titers 1:64–1:512). Risk factor analysis revealed that the variable female sex (cows) and the extensive farming system were statistically significantly associated with seroprevalence for N. caninum. Whereas for T. gondii, extensive farming, frequent animal purchase, and the lack of separation between calves and adult cattle were statistically significant. These findings demonstrate the circulation of these parasites in herds, with implications for animal and public health, indicating a potential risk of transmission to definitive hosts and humans through the consumption of raw or undercooked infected meat.

Ruminants doi: 10.3390/ruminants5040047

Authors: Emmely Pamela Dimas Villalobos Diana Sofía Torres Velázquez Efren Delgado Elia Esther Araiza Rosales Hiram Medrano Roldán Jorge Iñaki Gamero Barraza Gerardo Antonio Pámanes Carrasco Jesús Bernardo Páez Lerma María Inés Guerra Rosas Damián Reyes Jáquez

Livestock production raises significant environmental concerns, necessitating the development of sustainable feeding strategies based on non-conventional forages, such as locally available vegetation. This study evaluated the effects of a pelleted concentrate containing 10% Acacia farnesiana leaves as a dietary supplement on in vitro ruminal fermentation. Four experimental diets were formulated with increasing levels of the concentrate (0%, 25%, 50%, and 75%). Analyses were performed in triplicate and included chemical composition, in vitro gas and methane production, fermentation kinetics, ammonia nitrogen concentration (N–NH3), in vitro dry matter digestibility (IVDMD), and metabolizable energy (ME) estimation. The results revealed no significant differences (p > 0.05) in most gas production kinetic parameters, overall fermentation patterns, or metabolizable energy. In contrast, a significant increase (p < 0.05) in secondary metabolite concentrations was detected. While methane production remained unaltered (p > 0.05), a significant linear reduction was observed for IVDMD, the lag phase (L), and N–NH3 concentration (p = 0.0064, p = 0.0036, and p < 0.0001, respectively). These findings suggest that A. farnesiana can be incorporated into ruminant concentrates without increasing methane emissions. However, in vivo trials and mechanistic studies are required to validate and further elucidate these results.

Ruminants doi: 10.3390/ruminants5040046

Authors: Paolo César Cano-Suárez Juan Pablo Damián Rosalba Soto Karen Guadalupe Ayala-Pereyro Rocío Ibarra-Trujillo Laura Castillo-Hernández Enrique Flores-Gasca Rocío Morales-Méndez Jorge Eduardo Mendoza-Flores Angélica Terrazas

No studies have induced maternal behavior in goats through hormonal treatment. We evaluated whether ovariectomized goats treated with estradiol benzoate (EB2; n = 7 nulliparous and 10 multiparous goats) or progesterone + estradiol benzoate (P4 + EB2; n = 7 nulliparous and 7 multiparous goats), before or after vagino-cervical stimulation (VCS), displayed maternal behavior. When all goats were measured within treatments, in the EB2 group, low-pitch bleats were more frequent, and the time spent cleaning the kids was longer after VCS (p < 0.01), while location changes were more frequent before VCS. In nulliparous goats, those in the EB2 group emitted more low-pitch bleats after VCS than before (p = 0.04). The frequency of location changes was higher before VCS than after (p = 0.05). In multiparous goats, the frequency of smelling the kids and aggression toward the kids before VCS was higher in the EB2 group than in the P4 + EB2 group (p < 0.01). Within treatments, the EB2 group emitted more low-pitch bleats after VCS than before (p = 0.01), and the duration of cleaning the kids was longer after VCS than before (p = 0.028). Within the P4 + EB2 group, the kids were smelled more frequently after VCS than before (p = 0.03). The maternal index after vagino-cervical stimulation was higher in goats with EB2 (p = 0.002). Nulliparous goats treated with P4 + EB2 had a higher maternal index compared with those treated with EB2 alone (p = 0.04). In conclusion, regardless of parity, maternal behavior induced with the EB2 treatment was better when VCS was applied. Likewise, maternal experience altered the response. In multiparous females, any of the treatments were better after VCS, while in nulliparous females, this was only evident with the EB2 treatment.

Ruminants doi: 10.3390/ruminants5030045

Authors: Nicole A. Bloch Cheyenne L. Runyan Janice L. Speshock Barry D. Lambert Kimberly B. Wellmann Kara Tifft Jeff A. Brady

Microbiomes have become an increasingly important field of study in the past decade, with data supporting microbial roles in disease control, metabolic efficiency, and more. Microbial DNA is detectable outside the digestive tract, including in blood. Bloodborne pathogens such as hemotrophic Mycoplasma are endemic in cattle. Hemoplasmas are associated with reduced male fertility and decreased milk production in dairy cattle, but their impact on beef cattle remains unclear. Strain variability, such as between the Massachusetts and INFAP01 strains of Mycoplasma wenyonii, may complicate detection. Coinfection with multiple species likely contributes to disease progression from latent to acute infection. To assess microbial DNA in blood and quantify erythrocytic M. wenyonii, blood was collected from 120 beef cattle in Erath County, Texas: 61 cows, 55 calves, and 4 bulls. DNA was extracted and used to prepare 16S rRNA V4 libraries and perform PCR. After rarefaction, ASVs were analyzed and separated into four groups: adult females (n = 61), adult males (n = 4), juvenile males (n = 27), and juvenile females (n = 28). Statistical analysis revealed differences in Actinobacteria by sex (p < 0.001) and higher Bartonella and Mycoplasma abundances in adults (p < 0.001). PCR revealed that M. wenyonii infection was more frequent in adult females (p = 0.006), suggesting age-related variation in infection.

Ruminants doi: 10.3390/ruminants5030044

Authors: Blanca Isabel Sánchez-Toledano Marco Andrés López-Santiago Jorge Alonso Maldonado-Jáquez Karim Antonio Carreón-Negrete Juan José Figueroa-González Lorenzo Danilo Granados-Rivera

The present study aimed to determine whether enriching the finishing ration of lambs with incremental doses of a protected fatty acid (FA) blend would result in noticeable differences in the eating experience of the resulting meat. Three isonitrogenous diets containing 0, 50, or 100 g day−1 of the FA mixture were formulated, and the lambs were fed these diets until slaughter under otherwise identical management conditions. After postmortem aging, boneless loin samples from each treatment were submitted to a descriptive sensory evaluation by a rigorously trained panel that followed international guidelines. Multivariate techniques—principal component analysis combined with hierarchical clustering—were applied to integrate the panel’s quantitative scores and visualize how the treatments segregated in sensory space. The lamb meat presented a level of acceptance dependent on the proportion of fatty acids. In general, this study suggests that adding an extra 50 or 100 g of fat supplement to a lamb’s diet towards the end of its growth can significantly improve the enjoyment consumers get from eating the meat. Sensory analysis of lamb meat enriched with fatty acids indicated that the most important attributes determining the acceptance of lamb meat were color, flavor, odor, and toughness. Consequently, it can be recommended that dietary fatty acids be strategically increased during the finishing phase as a practical approach to enhancing the sensory appeal of sheep meat without compromising panel consensus.

Ruminants doi: 10.3390/ruminants5030043

Authors: Cesar Cristiano Bassetto Michelle Cardoso Santos Natalia Mizuhira Magro Alessandro Francisco Talamini do Amarante

Haemonchus contortus and Haemonchus placei infect different species of ruminants, but when small ruminants and cattle share the same pasture, cross-infections can occur. Weather conditions and the herbage microenvironment influence the development and survival of larvae during the free-living stage. Development of free-living stages (eggs, L1, L2, and L3) for both nematode species in sheep faeces deposited on short grass (4 cm) and tall grass (60 cm) ground was evaluated during nine days at the beginning of the rainy season. Rainfall occurred during five of the nine days assessed, and the tall and short grass environments demonstrated different temperatures, with a maximum of 34.0 °C to 42.0 °C and 31.0 °C to 38.0 °C and a minimum of 12.0 °C to 17.0 °C and 10.0 °C to 24.5 °C for the short and tall grass, respectively. Due to the development of eggs into infective larvae (L3), decreased egg counts were observed over time in faecal samples from both species and environments. However, some eggs were still present in samples until eight days post-deposition among tall grass. In both environments, the development times for all larval stages were similar. Small numbers of H. contortus larvae were found in the soil and grass, whereas no H. placei larvae were found. In conclusion, the trend of development in different environments was similar for both nematode species; however, the tall grass environment provided better conditions for the development of larval stages of both Haemonchus species.

Ruminants doi: 10.3390/ruminants5030042

Authors: Methun C. Dey Gauri Jairath Ishaya U. Gadzama Susana P. Alves Eric N. Ponnampalam

Feeding a balanced diet such as total mixed ration (TMR) is a widely adopted feeding strategy providing a uniformly blended diet of roughages, concentrates, and supplements that enhances ruminant productivity by optimizing nutrient utilization, stabilizing rumen fermentation, and improving microbial activity. Scientific studies have confirmed that TMR increases dry matter intake (DMI), milk yield, and growth performance in dairy and beef cattle, as well as in sheep and goats. TMR’s advantages include consistent feed quality, reduced selective feeding, and improved feed efficiency. A key benefit of TMR is its ability to promote the production of volatile fatty acids (VFAs), which are the primary energy source for ruminants, particularly propionate. This enhances energy metabolism, resulting in higher carcass yields, increased milk production, and economic benefits compared to conventional or supplementary feeding systems. However, TMR feeding is also susceptible to mycotoxin contamination (e.g., aflatoxins, zearalenone), potential effects on methane emissions, and the need for precise formulation to maintain consistency and optimise profitability. Prevention and good practices, including routine inspection of feed for pathogens and vulnerable ingredients, as well as careful management of particle size and forage-to-concentrate ratios, are crucial in preventing subacute ruminal acidosis (SARA) and the development of other subclinical diseases. Mycotoxin binders, such as hydrated sodium calcium aluminosilicate, can also reduce mycotoxin absorption. Another advantage of practicing TMR is that it can support sustainable farming by integrating agro-industrial byproducts, which minimises environmental impact. In conclusion, TMR is a widely adopted feeding strategy that significantly enhances ruminant productivity by optimizing nutrient utilization, stabilizing rumen fermentation, and improving microbial activity, leading to increased dry matter intake, milk yield, and growth performance. It offers key benefits such as consistent feed quality, reduced selective feeding, improved feed efficiency, and enhanced energy metabolism, providing economic advantages and supporting sustainable farming through agro-industrial byproduct integration. However, its implementation requires careful management to mitigate risks, including mycotoxin contamination, potential impacts on methane emissions, and digestive issues like SARA if formulation is not precise. Therefore, for sustainable production, future research should focus on optimizing TMR formulations with alternative ingredients (e.g., agro-industrial byproducts) and precision feeding strategies to enhance livestock health and animal productivity while minimizing environmental impacts.

Ruminants doi: 10.3390/ruminants5030041

Authors: Elizabete Cristina Batista da Costa Macena Roberto Germano Costa Wandrick Hauss de Sousa Felipe Queiroga Cartaxo Francisco Fernando Ramos de Carvalho Neila Lidiany Ribeiro

This study aimed to evaluate the effects of age and sex on carcass traits, commercial cuts, and meat quality in crossbred kids. A total of 32 Boer × native crossbred kids were used, equally distributed according to sex and slaughter age: 16 male kids (8 slaughtered at 70 days and 8 at 100 days) and 16 female kids (8 at 70 days and 8 at 100 days). However, slaughter age significantly affected (p < 0.05) total weight gain, empty body weight, hot and cold carcass weights, loin eye area, internal fat percentage, and carcass compactness index. A significant interaction (p < 0.05) between sex and age was found for thoracic depth. In addition, leg length and leg compactness index were significantly influenced (p < 0.05) by both factors. Slaughter age also had a significant effect (p < 0.05) on internal body length, leg length, rump width, thigh perimeter, rump perimeter, chest circumference, thoracic depth, internal thoracic depth, and carcass compactness index. Regarding commercial cuts (neck, shoulder, ribs, loin, and leg), slaughter age had a significant influence (p < 0.05), reflecting the same pattern observed in hot and cold carcass weights, and indicating consistent distribution across cuts. In conclusion, slaughter age had a more pronounced effect on carcass characteristics than sex, highlighting its importance in determining meat yield and quality in crossbred kids.

Ruminants doi: 10.3390/ruminants5030040

Authors: Ahmed Mohamed Hussein Fage Farrag Mohamed Nageib El-Arian El-Shafe Abdel Kader Omer Adel Salah Khattab Oludayo Michael Akinsola Thiruvenkadan Aranganoor Kannan

Selection indices enhance dairy cattle breeding by optimizing multiple traits simultaneously. This study analyzed 2181 lactation records from Holstein–Friesian cows at Sakha Experimental Farm, Egypt, to evaluate selection indices for 305-day milk yield (MY), fat yield (FY), and protein yield (PY) using two relative economic value (REV) methods: actual economic values (REV1) and one phenotypic standard deviation (REV2). Using MTDFREML software, we estimated heritabilities of 0.27 ± 0.01 (MY), 0.22 ± 0.01 (FY), and 0.28 ± 0.02 (PY). Four selection indices were constructed based on actual relative economic values (REV1) and one phenotypic standard deviation (REV2). The comprehensive index (I1) incorporated all three key production traits, viz., MY, FY, and PY, to maximize the genetic merit of the aggregate genotype. In contrast, the reduced indices (I2, I3, and I4) included only two traits each. The I2 incorporated MY and FY, the I3 included MY and PY, and the I4 included FY and PY. The index I1 (including all traits) yields the highest genetic gains (305 kg MY, 14.0 kg FY, 11.93 kg PY per generation). Both REV methods produced comparable genetic gains, but REV2 is recommended for its computational simplicity. These findings support the use of selection indices for genetic improvement in Holstein–Friesian cows, offering practical guidance for dairy breeding programs in Egypt and similar environments.

Ruminants doi: 10.3390/ruminants5030039

Authors: Alperen Varalan Burak Barit Burak Mat Mustafa Bahadır Çevrimli Aytekin Günlü

This study aims to analyze the technical and economic infrastructure of sheep farming enterprises operating in Türkiye. It assesses the demographic characteristics of enterprise owners, enterprise scales, production objectives, marketing strategies, and economic performance. Primary data were collected through face-to-face surveys conducted with 201 sheep farming enterprises during the 2023 production period. The sample was selected based on information provided by the Provincial Directorates of Agriculture and Forestry and the Breeding Sheep and Goat Breeders’ Associations. Data analysis was performed using SPSS 27. Categorical data related to enterprise characteristics and the demographic profiles of enterprise owners were examined. The findings indicate that the majority of enterprise owners are middle-aged or older individuals, have a low level of education, and operate predominantly within an extensive production system. The producers’ marketing methods rely mainly on direct sales. In conclusion, ensuring the sustainability of the sheep farming sector requires encouraging young producers to enter the industry, expanding educational programs, and adopting modern production techniques.

Ruminants doi: 10.3390/ruminants5030038

Authors: Elena Niceas Martínez Rodrigo Muíño Joaquín Hernández Bermúdez Lucia Díaz González Jose Luis Benedito Cristina Castillo

MFD is a nutritional disorder in dairy cattle characterized by a reduction in milk fat content despite a normal or increased milk yield. This review synthesizes current knowledge on the biological mechanisms and nutritional factors contributing to the development of this condition. Disruptions in rumen fermentation and alterations in fatty acid biohydrogenation (particularly the formation of trans-10 fatty acids) are recognized as central contributors to MFD. Several theories have been proposed to explain its pathophysiology, including the glucogenic, volatile fatty acid, trans fatty acid, and biohydrogenation theories. MFD is most commonly associated with diets low in fiber and high in polyunsaturated fatty acids or starch, which promote the accumulation of fatty acid intermediates that inhibit mammary lipogenesis. Among these, trans-10, cis-12 conjugated linoleic acid is particularly notable for its potent suppression of de novo fatty acid synthesis in the mammary gland. While proper dietary formulation remains the most effective preventive strategy, nutritional interventions such as magnesium-based alkalinizers, sodium bicarbonate, intravenous arginine, and vitamin E have shown promise in mitigating established cases. This review underscores the importance of nutritional management in preserving milk fat synthesis and promoting overall animal health.

Ruminants doi: 10.3390/ruminants5030037

Authors: Iran Alves Torquato Cleber Thiago Ferreira Costa Meirielly Santos Jesus Fernando Mata Joana Santos Hortência E. Pereira Santana Daniel Pereira Silva Denise Santos Ruzene

The success of optimal ruminant production relies heavily on feed efficiency to deliver the necessary nutrients to animals. Nutritional deficiencies in livestock pose a significant challenge in regions experiencing prolonged fluctuations in resource availability and quality. In this context, the present study aimed to investigate the cumulative gas production (CGP) and in vitro degradability of silages made from spineless forage cactus (a native species) combined with high-fiber ingredients, to evaluate their viability as a sustainable, low-cost alternative to animal feed. The experiment involved ensiling spineless cactus genotypes with varying levels of sugarcane bagasse (0, 150, 300, 450, and 600 g/kg of dry matter) and a 1% urea–ammonium sulfate solution. The results indicated that for all genotypes studied, the CGP curves from silage composed solely of forage cactus differed significantly from those containing bagasse, which exhibited an initial phase characterized by little or no gas production. In vitro degradability was negatively influenced by the inclusion of bagasse at any level, resulting in decreased dry matter and organic matter degradability, as well as reduced CGP with increasing bagasse concentration. Therefore, the study demonstrated that the proposed combination of ingredients represents a promising sustainable feed supplement to enhance animal nutrition. Silage containing 150 g/kg of bagasse treated with urea offers a favorable balance between the energy required by rumen microflora and the benefits of fiber presence.

Ruminants doi: 10.3390/ruminants5030036

Authors: Zonaxolo Ntsongota Olusegun Oyebade Ikusika Thando Conference Mpendulo

Ruminant livestock production plays a crucial role in the agricultural systems of Sub-Saharan Africa, significantly supporting rural livelihoods through income generation, improved nutrition, and employment opportunities. Despite its importance, the sector continues to face substantial challenges, such as low feed quality, seasonal feed shortages, and climate-related stresses, all of which limit productivity and sustainability. Considering these challenges, the adoption of natural feed additives has emerged as a promising strategy to enhance animal performance, optimise nutrient utilisation, and mitigate environmental impacts, including the reduction of enteric methane emissions. This review underscores the significant potential of natural feed additives such as plant extracts, essential oils, probiotics, and mineral-based supplements such as fossil shell flour as sustainable alternatives to conventional growth promoters in ruminant production systems across the region. All available documented evidence on the topic from 2000 to 2024 was collated and synthesised through standardised methods of systematic review protocol—PRISMA. Out of 319 research papers downloaded, six were included and analysed directly or indirectly in this study. The results show that the addition of feed additives to ruminant diets in all the studies reviewed significantly (p < 0.05) improved growth parameters such as average daily growth (ADG), feed intake, and feed conversion ratio (FCR) compared to the control group. However, no significant (p > 0.05) effect was found on cold carcass weight (CCW), meat percentage, fat percentage, bone percentage, or intramuscular fat (IMF%) compared to the control. The available evidence indicates that these additives can provide tangible benefits, including improved growth performance, better feed efficiency, enhanced immune responses, and superior meat quality, while also supporting environmental sustainability by reducing nitrogen excretion and decreasing dependence on antimicrobial agents.

Ruminants doi: 10.3390/ruminants5030035

Authors: Panagiotis D. Katsoulos Bengü Bilgiç Duygu Tarhan Fatma Ateş Suat Ekin Süleyman Kozat Banu Dokuzeylül Mehmet Erman Or Emmanouil Kalaitzakis Georgios E. Valergakis Nikolaos Panousis

Due to the feeding system (high-concentrate diet) during the early lactation stage, ruminal pH in dairy cows follows a diurnal pattern and can remain below the critical level of 5.5 for extended periods of the day. This study aimed to evaluate the effect of low ruminal pH on blood concentrations of certain macrominerals, trace minerals, and fat-soluble vitamins and on the oxidative status of dairy cows during the first half of lactation. Fifty-three randomly selected lactating Holstein cows were used; blood and ruminal fluid samples were collected from all cows on days 30, 90 and 150 of lactation. Blood samples were obtained via coccygeal venipuncture, while the ruminal fluid was obtained by rumenocentesis and the pH was measured immediately after collection. Using a threshold pH of 5.5, samples were classified as normal (pH > 5.5) or low pH (pH ≤ 5.5). Serum concentrations of Ca, Mg, K, Cr, Mn, Zn, Se, and vitamins A, D3, E, and K were not significantly affected by ruminal pH, either by days in milk or by their interaction (p > 0.05). Plasma malondialdehyde and reduced glutathione followed the same trend (p > 0.05). Copper concentration was significantly higher (p < 0.05), and Fe concentration tended to be higher in cows with low pH compared to those with normal pH (p = 0.052). On day 150 of lactation, Cu, Fe, and Co concentrations were significantly higher in low-pH cows compared to normal-pH cows (p < 0.05). Low ruminal pH is associated with significant changes in serum concentrations of copper, iron, and cobalt but has no significant effect on the oxidative status of the animals or on the serum concentrations of the macro elements and fat-soluble vitamins studied.

Ruminants doi: 10.3390/ruminants5030034

Authors: Maria De Bernardi Carlee M. Salisbury Haley E. Larson Matthew R. Beck Logan R. Thompson

The objective of this analysis was to compare the greenhouse gas (GHG) emissions from contemporary grazing cattle production with bison grazing, both modern and historical. The data sets used in this analysis were derived from existing research and conservation properties located outside of Manhattan, KS (USA), which are home to stocker cattle, cow–calf production (CCS), and grazing bison. For stocker cattle, 10 years of animal production data (2007–2016) from season-long stocking (SLS, grazing 156 d) and intensive early stocking systems (IES; 76 grazing d and 2× stocking density) were used for GHG calculations. Enteric CH4, manure CH4, and direct nitrous oxide emissions were estimated using the IPCC tier 2 methodology. Historic bison (HGB) enteric CH4 estimates were calculated using a stocking density of 0.15 ha/animal and assuming that only 13% of grassland was used by bison each year. Within contemporary systems, IES had the lowest emissions (463.3 kg CO2-eq./ha/yr), while SLS, CCS, and MGB had the highest estimates (494.7, 493.9, and 595.9 kg CO2-eq./ha/yr, respectively). HGB had the lowest estimated annual emissions at 295.7 kg CO2-eq./ha/yr. These results imply that the historic grazing baseline of this grassland system is lower but similar to that of contemporary grazing cattle in the Great Plains region.

Ruminants doi: 10.3390/ruminants5030033

Authors: Arcesio Salamanca-Carreño Pere M. Parés-Casanova Mauricio Vélez-Terranova David E. Rangel-Pachón Germán Martínez-Correal Jaime Rosero-Alpala

Geometric morphometrics is performed on different species in different contexts. Here, the aim was to investigate morphological differences in the head of the Sanmartinero Creole bovine to examine head shape variations between sexes using geometric morphometric methods. A sample of cranial pictures of 43 animals (13 males and 30 females) was obtained, and form (size + shape) was studied by means of geometric morphometric techniques using a set of 14 landmarks. This approach eliminated potential dietary effects, ensuring that the observed shape variations were primarily due to intrinsic morphological differences. Sexual dimorphism was found in form (for both size and shape) of the head of the Sanmartinero Creole bovine breed. Males had significantly larger heads based on centroid size (U = 714, p = 0.0004), confirming true sexual size differences, and Principal Component Analysis revealed overlapping head shapes with sexual dimorphism concentrated at midline sagittal landmarks (between the most rostral and caudal orbit points) and paired lateral points, indicating that males have broader and longer heads. The two evaluated characters (head size and shape) are of special interest for the conservation of the breed, especially in those cases whose objectives are to maintain the uniqueness, distinctiveness, and uniformity of the populations. This study analyzed animals subjected to the same feeding program, ensuring the elimination of additional variables.

Ruminants doi: 10.3390/ruminants5030032

Authors: José Alejandro Roque-Jiménez Lorena Diaz de León-Martinez German David Mendoza-Martínez Rogelio Flores-Ramírez Guillermo Espinosa-Reyes Alejandro E. Relling Ulises Macias-Cruz Marisol López-Romero Héctor Aarón Lee-Rangel

The aims of the current study were to characterize the natural compounds of Salsola tragus via GC-MS and determine its effects as a forage source on lamb growth, in vitro rumen fermentation kinetics, carcass quality, cellular damage, and metabolomic meat interaction. Twenty-one Rambouillet lambs were randomly assigned to one of three experimental diets (seven lambs per treatment): (1) a control diet (W/o-Salsola) containing 300 g/kg dry matter (DM) of sorghum stover; (2) a diet with a medium inclusion of Salsola tragus (15-Salsola), which contained 150 g/kg DM of Salsola tragus and 150 g/kg DM of sorghum stover; and (3) a diet comprising 300 g/kg of Salsola tragus (30-Salsola). The results showed there were no differences (p > 0.05) in lamb growth performance during the fattening phase. The in vitro gas analysis demonstrated that the 30-Salsola treatment increased lag time h−1 (p < 0.05) and reduced gas production (p = 0.03). The metabolomic analysis findings suggest that the treatments that included Salsola tragus significantly positively affect the metabolomic composition of meat (p < 0.05). The use of 15-Salsola as a source of forage is promising for feeding lambs during the fattening phase.

Ruminants doi: 10.3390/ruminants5030031

Authors: Katharina Padberg Ulrich Meyer Dirk von Soosten Fabian Billenkamp Liane Hüther Christin Unruh Christian Visscher Sven Dänicke

A key factor in calculating dairy cows’ nitrogen (N) excretion is knowing the amount of daily excreted urine. The present study aimed to investigate two methods to calculate the daily urine volume (UV) excreted using spot urine samples. Data were obtained from nine balance experiments involving 47 lactating and seven non-lactating German Holstein cows, with an average body weight (BW) of 620 ± 95 kg and an average age of 5.6 ± 1.4 years. Daily urinary creatinine (Cr) and UVs were known for all animals. The first method was developed by linearly regressing the daily excreted amount of Cr in urine against BW (p < 0.001; R2 = 0.51; RSE: 2.8). The slope of the regression was used to calculate UV. The second method includes a non-linear regression of UV on Cr concentration in urine, allowing direct estimation of UV without knowledge of BW (p < 0.001; RSE: 8.13). Both estimation methods were compared to the standard method to determine UV from balance trials using Lin’s concordance correlation coefficient (CCC) and Bland–Altman plots. The first method had a CCC of 0.81, and the second method had a CCC of 0.85. Both methods can confidently be applied to calculate UV. Therefore, the second method is usable if BW is unavailable.