Search Results (131)

Heat stress, particularly during the prepartum period, compromises dairy cow health and has lasting effects on offspring. This study aimed to investigate the effects of maternal yeast culture (YC) supplementation during heat stress on the intestinal health of newborn calves, with a specific focus on elucidating the associated changes in jejunal morphology, microbial community, and metabolic profiles. Cows receiving YC had lower rectal temperatures, confirming mitigated heat stress. Their calves showed enhanced immune status (higher IgA, IgG) and reduced oxidative stress and metabolic markers. Jejunal structure and barrier integrity were improved. While microbial diversity was similar, specific bacterial abundances differed (e.g., Enterococcus spp. enriched in YC calves). Metabolomic analysis revealed modulated bile acid pathways and metabolites in YC calves, correlating with the microbial shifts. In conclusion, maternal YC supplementation during heat stress supports calf early-life gut health and development through maternal-offspring programming, optimizing gut microbiota, metabolism, and immunity. Full article

This study evaluated the effects of straw particle size (short or long) and corn physical form (ground or whole) in diets on growth performance, rumen fermentation and fecal score in calves. Sixty female newborn calves were randomly assigned to one of the four treatments: 90% pelleted starter and 10% short straw (PSS); 70% pelleted starter, 20% whole corn and 10% short straw (PWCSS); 90% pelleted starter and 10% long straw (PLS); 70% pelleted starter, 20% whole corn and 10% long straw (PWCLS). In PSS and PLS treatments, all of the corn was within the pelleted starter. Calves were weaned at 68 days of age. Body weight (BW), wither height and heart girth were measured at 3 and 68 days of age. Feed intakes and fecal scores were measured daily. Rumen fluid and blood samples were collected for rumen pH, rumen volatile fatty acid (VFA) and blood β-hydroxy butyrate (BHB) measurements at 68 days of age. Weaning BW, average daily weight gain (ADG) and weaning wither height were significantly lower in PLS compared to other treatments. Weaning heart girth was significantly lower in PSS and PLS than PWCSS and PWCLS. Feed intake was significantly higher for PWCSS than PWCLS. PWCLS had a significantly lower feed efficiency (starter feed intake/ADG) than PLS. No significant differences were observed for ruminal pH, ruminal acetate and blood BHB among the treatments. In the diets including short straw, ruminal propionate, butyrate and total VFA concentrations were significantly higher for PWCSS than PSS. In the diets including long straw, the ruminal propionate concentration was significantly greater for PLS than PWCLS, and ruminal butyrate and total VFA concentrations were not different for PLS and PWCLS. This study indicated that the effect of corn physical form (ground or whole) on ruminal propionate, butyrate and total VFA concentrations could vary depending on straw particle size. Fecal score was significantly lower in PSS compared to other treatments. In conclusion, long straw combined with pelleted concentrate reduced growth performance in pre-weaning calves. Whole corn inclusion in the diets with long straw increased ADG and weaning BW and improved feed efficiency. Full article

Early-life development of immune functions is crucial for calf health, growth, and future productivity. Galacto-oligosaccharides (GOSs) have been reported to facilitate ruminal microbial establishment and improve growth in Holstein dairy calves, but their prolonged influence on immunoglobulin levels, hindgut microbiota, and metabolic regulation remains insufficiently understood. This study evaluated the effects of early-life GOS supplementation on immune-related indicators, intestinal microbial ecology, and metabolic profiles in Holstein calves. Twenty-four newborn Holstein female dairy calves were randomly assigned to a control group (CON, n = 12) or a GOS group (GOS, n = 12; 10 g/day from birth to day 28). After supplementation ceased on day 28, calves previously receiving GOS were referred to as the GOSS group (n = 6). Immunoglobulin levels, gut microbiota, and fecal and serum metabolomes were evaluated during supplementation and six weeks after withdrawal. GOS supplementation significantly increased serum IgA and IgG levels during the treatment, with IgG levels remaining elevated for six weeks after discontinued supplementation. Although overall microbial diversity was not markedly altered, GOS selectively enriched bacterial taxa and function pathways linked to amino acid synthesis, unsaturated fatty acid production, and coenzyme-related metabolism. On day 70, GOSS group displayed distinct fecal and serum metabolomic profiles, with altered metabolites primarily associated with vitamin B6, folate, cobalamin metabolism, branched-chain amino acid biosynthesis, and purine and arginine pathways. These results demonstrate that early-life GOS supplementation promotes sustained immune and metabolic alterations following supplementation cessation, potentially mediated by modulation of gut microbial functions. These findings suggest that early dietary GOS supplementation may support physiological maturation in calves and could be useful as a nutritional strategy in calf-rearing systems. Full article

Neonatal and weaning periods are the most challenging phases for enteric infections in dairy calves. While different approaches are used to minimize calf health issues, the neonatal diet remains the core approach to enhance pre- and post-weaning animal health and performance. This pilot study aimed to evaluate blood biomarkers of inflammation and fecal metabolites in calves supplemented with oligosaccharide mixture (OS) during the preweaning stage. Sixteen newborn Holstein dairy calves (eight females and eight males) were randomly assigned into two groups: control with no supplementation, or treatment with 50 g/day of OS added to the pasteurized waste milk feeding. Both control and OS-treated calves were fed pasteurized waste milk during the preweaning period and weaned at seven weeks of age. Blood and fecal samples were collected weekly. Fecal fatty acid metabolites were downregulated in treated calves compared to control calves (p ≤ 0.05). Markers of inflammation (i.e., haptoglobin) or liver response (i.e., albumin, paraoxonase) did not differ between groups (p > 0.05). Overall, these findings suggest that dietary intervention with oligosaccharides can affect host metabolic pathways. Full article

Passive transfer of immunoglobulin G (IgG) through colostrum is essential for early immune protection in dairy calves. This systematic review synthesizes the most relevant evidence on colostrum quality, feeding practices, storage methods, and post-feeding assessment. High-quality colostrum (≥50 g/L IgG and low bacterial contamination) can be reliably assessed using Brix refractometry (≥22%) or radial immunodiffusion. Early administration is critical: feeding within 1–2 h after birth maximizes IgG absorption. Providing 8.5–10% of body weight (≈3–4 L) at first feeding, followed by a second feeding within 8–12 h, significantly reduces failure of passive transfer. Pasteurization at 60 °C for 60 min and controlled freezing maintain immunological integrity while reducing microbial load. Monitoring passive immunity using serum total protein (5.0–5.5 g/dL) or serum Brix (8.1–8.5%) offers practical field diagnostics aligned with the IgG ≥ 10 g/L threshold. Integrated colostrum management protocols—combining quality evaluation, timely feeding, hygienic handling, and trained personnel—are essential to improve passive immunity, health, and overall performance of dairy calves. Full article

Background/Objectives: Bovine colostrum, the initial milk produced by cows postpartum, contains an array of key nutritional, immune, and microbial components that support the calf’s physiological development, immune maturation, and intestinal colonization. The composition and quality of colostrum can be influenced by multiple factors, including seasonal variation, breed, parity, and farm management practices. This study investigated the microbial profile of Irish bovine colostrum and the influence of antibiotic therapy and parity. Methods: Bovine colostrum samples were collected from five Irish dairy farms that implemented different methods of dry cow therapy (DCT): natural or blanket. For blanket DCT, four of the five farms administered intramammary antibiotics at the start of the drying off period. Two farms administered a fourth-generation cephalosporin, cefquinome, and two farms used an antibiotic of the penicillin class, with the active ingredients consisting of procaine benzylpenicillin, penethamate hydriodide, and framycetin sulphate. One farm did not administer antibiotics but applied a teat sealant (natural DCT). Following calving, colostrum samples from 90 healthy dairy cows were analysed. Results: 16S rRNA sequence analysis revealed Firmicutes, Actinobacteriota, Bacteroidota, and Proteobacteria as the most abundant phyla across all treatment groups, with Acinetobacter, Corynebacterium, Facklamia, Jeotgalicoccus, Lactococcus, Leuconostoc, Psychrobacter, and Staphylococcus dominating at genus level. Parity did not significantly affect the microbial composition in this study, but antibiotic treatment did. Cows receiving no antibiotics showed distinct microbial clustering compared with antibiotic-treated cows (β-diversity, p < 0.001). Microbial diversity also differed between the antibiotic-treated groups, with significant changes in both α-diversity (p < 0.01) and β-diversity (p < 0.001), suggesting that the choice of antibiotic may also influence the microbiota. An influence of farm was also observed. Differential abundance analysis showed no increase in mastitis-associated genera in colostrum following natural DCT, although increased abundance was demonstrated with blanket DCT. Conclusions: Our findings substantiate the diverse and unique microbial composition of bovine colostrum. The data indicate that the microbial profile of bovine colostrum is influenced by antibiotic treatment administered during the dry period and affirms the latest policies inhibiting prophylactic antibiotic administration. Future studies should elucidate strain level changes in the colostrum microbiota following on-farm antibiotic use, assess the associated risks of antimicrobial resistance, and explore non-antibiotic alternatives for drying off cows. Evidently, the microbial composition of bovine colostrum is influenced by farm management strategies and optimizing these measures may further increase the valuable constituents of bovine colostrum and confer added health benefits to the new-born calf. Full article

Objectives: Bovine coronaviruses (BCoV) are endemic worldwide, causing diarrhea, winter dysentery, and bovine respiratory disease in newborn calves. These lead to higher calf mortality, reduced growth of fattening cows, and lower milk production in adult cows, resulting in significant losses to the cattle industry. Since commercial preventive drugs are not available in China, and existing treatments can only reduce the mortality of sick calves without fundamental control, the development of safe and effective vaccines is crucial. Methods: Two mRNA vaccines targeting the BCoV spiny receptor-binding domain (S-RBD) were prepared: XBS01 and XBS02. These two mRNAs, optimized for coding by AI and encapsulated in lipid nanoparticles (LNPs), were injected intramuscularly into mice (10 μg per mouse, twice, 2 weeks apart); a blank control group was not immunized. Serum antibodies, memory B/T cell activation and cytokine secretion were assessed by ELISA, flow cytometry and ELISpot. Results: Both vaccines induced humoral and cellular immunity:anti-S-RBD IgG titers were higher than those of the control group, and there was memory B-cell production and T-cell activation. XBS02 was superior to XBS01 in terms of peak antibody, memory B-cell frequency, T-cell activation rate, and IFN-γ/IL-2 secretion, and showed a stronger Th 1 response. Conclusions: Both BCoV S-RBD mRNA vaccines had good immunogenicity, with XBS02 providing better protection. This study supports the optimization and application of BCoV mRNA vaccines and accumulates data for mRNA technology in veterinary practice. Full article

This study investigated the effects of supplementing whole milk (WM) with sodium butyrate (SB) on the gastrointestinal microbiota of preweaned calves. Twelve newborn Holstein calves (4 days old, 39.21 ± 1.45 kg) were randomly assigned into one of two dietary treatments: (1) WM without SB (CON) and (2) WM supplemented with SB (8.8 g/d; SB). At 74 days of age, all calves were slaughtered to collect ruminal and cecal digesta. Metagenomic analysis was used to characterize the microbial composition, virulence factor genes (VFGs), and antibiotic resistance genes (ARGs). SB supplementation altered the ruminal microbial composition and increased the abundance of beneficial bacteria, including Actinobacteria, Bifidobacterium, and Olsenella (p < 0.05). Although SB did not significantly affect the overall microbial composition or diversity in the cecum (p > 0.05), it promoted the growth of beneficial genera such as Flavonifractor and Subdoligranulum (p < 0.05). Furthermore, SB supplementation did not significantly alter the composition of VFGs or ARGs in either the rumen or the cecum (p > 0.05). However, significant differences in VFGs and ARGs were observed between the rumen and the cecum, with a greater diversity of both VFGs and ARGs detected in the cecum compared to that in the rumen (p < 0.05). In summary, supplementing whole milk with sodium butyrate modulates gastrointestinal health in preweaned calves by favorably shaping the microbial community without significantly altering the antibiotic resistome or virulome. Full article

A healthy gut microbiota in calves is necessary for optimal performance and development. Considering that probiotics have been shown to improve gut microbiota, the aim of this study was to investigate the effects of Clostridium butyricum on growth performance, blood parameters, and gut microbiota in Hanwoo calves. In total, 92 calves from two farms were randomly assigned to four groups: a control and three treatment groups that received increasing doses of C. butyricum (CB1, CB2, and CB3) during the first 5 days after birth. Independent experiments were conducted at each farm with different measurements, where body weight was monitored and blood, rumen, and fecal samples were collected to assess physiological responses and microbial profiles. Notably, significant differences were observed in blood amylase and acid–base parameters, suggesting that C. butyricum supplementation may enhance metabolic stability and buffering capacity. Microbial profiling revealed preserved alpha diversity and compositional shifts in both the rumen and fecal microbiota. Particularly, there was an increase in the relative abundances of Prevotella and Muribaculaceae and a decrease in the abundances of the pathogenic genera Escherichia and Shigella in calves fed C. butyricum-supplemented diets. These changes, along with a trend toward a reduced frequency and severity of diarrhea, suggest that C. butyricum supplementation may support gut health and promote stable early growth in neonatal calves. Full article

Despite an abundance of available research, calf mortality persists as a multifaceted phenomenon that presents ongoing challenges in practical management. This historical single-cohort study was conducted to provide a more comprehensive layer of knowledge to the existing information pool on calf mortality risk factors by using multiblock partial least squares analysis. The method reveals the contribution of several variables aggregated into thematic blocks and allows to include multiple outcome variables describing the same phenomenon. Such an analysis of the data provides valuable information to farmers, veterinarians, and advisors alike, not only about single risk factors, but also about management areas to prioritize when tackling calf mortality. Data was gathered from 118 Estonian dairy herds, each comprising ≥100 cows, via questionnaire, sample collection, and on-farm scoring and measurements. The final dataset included 147 questions divided into 13 meaningful blocks. The outcome variables were annual herd-level calf mortality risk during the first 21 days (MR21) and 22–90 days (MR90) using farm records and the national cattle database, respectively. The average MR21 was 5.9% (median 4.4%, range 0.0–26.8%) and the average MR90 was 2.7% (median 2.3%, range 0.0–12.7%). Of the 13 thematic variable blocks, the most important blocks explaining calf mortality were ‘Routine stress-inducing activities’, ‘Herd characteristics’, ‘Calving management’, ‘Calf housing during 5–21 days’, and ’External biosecurity’. The most influential single variables associated with higher overall calf on-farm mortality during the preweaning period were poorer cleanliness scores of calving animals and calves having access to an outdoor area during the first 21 days of life. Detected risk factors for MR21 were calf barn age > 20 years, allowing the calves to suckle the first colostrum, bucket feeding calves during the first three weeks, disbudding all calves (compared to only heifer calves), and disbudding at 21–29 days of age. Risk factors for MR90 included the use of automatic milk feeders and feeding waste milk during the first three weeks, early introduction of calves to large group pens and higher in-pen age differences, absence of forced ventilation during the first three weeks, opportunity for feces to spread between calf pens, and use of calving pens for sick animals. Washing and disinfection of newborn calves’ pens and testing colostrum quality were protective factors against both MR21 and MR90. Other protective practices for MR21 were related to proper colostrum feeding routines, whereas lower MR90 was mostly associated with efficient external biosecurity practices and vaccination programs. The multiblock model proved to be beneficial in providing a broader understanding of the importance of different management areas on calf mortality. Full article

Pasteurized colostrum has significantly contributed to improving the health and growth of newborn calves by reducing total bacterial count. However, previous research on animal responses to pasteurized colostrum has primarily focused on physiological functioning and production performance, especially during the preweaning period, with limited attention to any postweaning effects from the feeding of pasteurized colostrum at birth. We conducted a comprehensive investigation into the growth, health, blood immunity, and microbiota responses of dairy calves in these two groups from birth to 180 d of age. In this study, a total of 32 healthy female Holstein calves [mean birth weight = 39.8 ± 1.22 kg (mean ± standard deviation)] were selected and divided into two groups (n = 16; fed either pasteurized or unpasteurized colostrum at birth). The results demonstrated that calves fed pasteurized colostrum exhibited enhanced growth performance as indicated by higher body weight (BW) and average daily gain (ADG) compared to those fed unpasteurized colostrum (p < 0.05). Calves fed pasteurized colostrum displayed higher lymphocyte ratio (W-SCR) and platelet distribution width (PDW), along with lower neutrophil ratio (W-LCR) and neutrophil count (W-LCC) (p < 0.05). Additionally, substantial differences were identified in microbial richness and diversity between the pasteurized and unpasteurized colostrum-fed groups (p < 0.05). Distinct microbial communities were observed in the ruminal and fecal regions (p < 0.05), and we detected shared beneficial microbiota (Alloprevotella, Parabacteroides, and unidentified_Prevotellaceae) and metabolic functions (metabolism of energy, amino acids, and glycan) in both gut regions of the pasteurized group. Furthermore, our study revealed intricate and robust interactions among microbiota, volatile fatty acid (VFA) and blood indicators (|r| > 0.5 and p < 0.05). In conclusion, the findings in the present experiment suggest that the positive effects from d 0 pasteurized colostrum feeding may be seen up to d 180, including improved growth performance, health, and blood immunity, and these may be attributed to modifications in microbiota development induced by pasteurized colostrum. Full article

Prepartum vaccination of dairy cows against newborn calf diarrhea protects calves during the first weeks of life via the colostrum. Vaccination may also induce non-specific effects (NSEs) beyond antibody production, altering the disease susceptibility and productivity of the vaccinated mother. This retrospective study analyzed herd records and on-site survey data from 73,378 dairy cows on 20 German farms using linear mixed-effects models and random forest algorithms. Management practices and milk yield showed stronger associations with outcomes than vaccination. However, the cows vaccinated with non-live vaccines had increased odds of retained placenta and metritis (OR: 1.5–1.7), as well as endometritis (OR: 3–6), and were 20–24% less likely to conceive than non-vaccinated cows. Among non-live vaccinated cows, those vaccinated 2.5–4 weeks before calving had an 8% higher non-return rate compared to those vaccinated 6–8 weeks prior. Multiparous cows receiving live vaccine components were 1.9 times more likely to conceive, compared to non-live vaccinated multiparous cows. These findings suggest potential NSE of prepartum vaccination on uterine health and fertility. However, this study’s retrospective design limits causal interpretation, and the benefits in calves may outweigh possible adverse effects. Further research should clarify the mechanisms and optimize vaccine timing and composition. Full article

This study investigated the effects of dietary supplementation with varying doses of Clostridium butyricum (C. butyricum) on growth performance, diarrhea incidence, serum biochemical parameters, fecal short-chain fatty acids (SCFAs), and fecal microbiota in preweaning Holstein calves. Forty healthy newborn Holstein heifer calves with comparable birth weights were randomly assigned to four groups (control, 1 g/d supplementation, 3 g/d supplementation, and 5 g/d supplementation) for a 60-day trial. Growth parameters, diarrhea incidence, serum immunoglobulins (IgA, IgG, IgM), cytokines (IL-1β, TNF-α), antioxidant indicators (T-AOC, MDA), fecal short-chain fatty acids (SCFAs), and microbial composition were measured to evaluate the effects of C. butyricum. The results indicated that calves in the 5 g/d group exhibited a significantly higher average daily gain (ADG) compared with the control group (804.67 vs. 701.67 g/d, p < 0.05), with no significant differences in feed intake observed among groups (p > 0.05). During Days 22–42, the diarrhea incidence in the 5 g/d group was 7.74% lower than that in the control group (p < 0.05). This group exhibited significantly elevated serum IgM levels (Day 42, p < 0.05) and reduced IL-1β concentrations (Day 42, p < 0.05). Additionally, total antioxidant capacity (T-AOC) was significantly enhanced (Days 42 and 60, p < 0.05), while malondialdehyde (MDA) content was significantly decreased (Days 21 and 42, p < 0.05). At Day 42, fecal propionate and butyrate concentrations were significantly elevated in the 5 g/d group (p < 0.05), while the relative abundances of Bacteroides, Acidaminococcus, Bifidobacterium, Olsenella, Faecalitalea, and Ruminococcus were significantly increased (p < 0.05). The increase in these short-chain fatty acids and beneficial bacteria contributes to improved intestinal health and thus helps alleviate diarrhea. These findings indicate that supplementing preweaning calves’ milk with 5 g/d of C. butyricum significantly enhances growth performance and intestinal health. This provides evidence for the use of C. butyricum as a natural alternative to antibiotics in calf rearing. Full article

Group A rotavirus (RVA) is a leading causative agent of diarrhea in both young animals and humans. In China, multiple genotypes are commonly found within the bovine population. In this study, we investigated 1917 fecal samples from calves with diarrhea between 2022 and 2025, with 695 testing positive for RVA, yielding an overall detection rate of 36.25%. The highest positivity rate was observed in Hohhot (38.98%), and annual detection rates ranged from 26.75% in 2022 to 42.22% in 2025. A bovine rotavirus (BRV) strain, designated 0205HG, was successfully isolated from a fecal sample of a newborn calf. Its presence was confirmed through cytopathic effects (CPEs), the indirect immunofluorescence assay (IFA), electron microscopy (EM), and high-throughput sequencing. Genomic characterization identified the strain as having the G6-P[1]-I2-R2-C2-M2-A3-N2-T6-E2-H3 genotype constellation. The structural proteins VP2 and VP7, along with nonstructural genes NSP1–NSP4, shared high sequence identity with Chinese bovine strains, whereas VP1, VP4, and NSP5 clustered more closely with human rotaviruses, and VP3 was related to feline strains. These findings highlight the genetic diversity and interspecies reassortment of BRVs in China, underlining the importance of continued surveillance and evolutionary analysis. Full article

The transfer of passive immunity (TPI) is vital for newborn calf health and is typically assessed through blood sampling to measure serum or plasma IgG or total protein levels. Saliva offers a less invasive alternative. This study evaluated the potential of saliva for assessing TPI. Saliva and serum samples were collected from 20 calves at birth and on days 1, 2, and 7 of life to measure IgG, IgA, IgM, and total protein concentrations. Colostrum fed to the calves was also analyzed for gross composition and immunoglobulin content. Colostrum intake and composition were associated with saliva IgG (R² = 0.48; p = 0.019), saliva IgM (R² = 0.73; p = 0.02), and saliva total protein (R² = 0.41; p = 0.043). Serum IgG and IgA levels were predicted by saliva IgG (p < 0.001; R² = 0.33) and IgA (p < 0.001; R² = 0.13), respectively, though predictive accuracy varied by calf age (IgG: p < 0.001; R² = 0.40; IgA: p < 0.001; R² = 0.91). In conclusion, the results suggest that both saliva IgG and IgA concentrations could be used to predict IgG and IgA serum concentrations. Nevertheless, further studies are still needed to clarify the best time for sample collection. Full article