Search Results (1,708)

This study evaluated the biological and economic impact of twin calvings in a commercial dairy herd located in Harghita County, Romania. Data from 2019 to 2022 were analyzed retrospectively using production, reproductive, and veterinary records. The incidence of twin pregnancies averaged 11.0% across the study period. Mixed-sex pairs were most frequent (55.3%), followed by female–female (28.2%) and male–male (16.5%) combinations. Twin calvings were associated with significant reductions in subsequent milk yield (−742 kg per lactation; p < 0.05), decreased fertility (2.3 vs. 1.4 inseminations; 103 vs. 79 days service period; p < 0.05), and higher veterinary costs (EUR 90 per case). The expected loss of replacement value due to freemartinism was EUR 63 per twin calving. After accounting for a small gain in calf value, the total economic loss was estimated at EUR 379 per twin calving. These findings demonstrate that twin pregnancies, although relatively uncommon, substantially reduce productive efficiency and profitability in dairy systems. Early detection and targeted reproductive management are recommended to mitigate their adverse effects and enhance farm sustainability. Full article

Macrolides are crucial for the management and treatment of bovine respiratory disease (BRD). However, antimicrobial resistance (AMR) threatens the efficacy of these and other antimicrobials. We developed real-time recombinase polymerase amplification (RPA) assays targeting three clinically relevant macrolide antimicrobial resistance genes (ARGs)—msrE-mphE and erm42—in ≤30 min using extracted DNA. A set of 199 deep nasopharyngeal swabs (DNPS) collected from feedlot calves near the time of arrival were selected based on bacterial culture (BC) results for Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni and antimicrobial susceptibility testing (AST) for tulathromycin, tilmicosin, tildipirosin, or gamithromycin. Samples were also tested for the same targets using RPA and polymerase chain reaction (PCR). In samples that were culture-positive for one or more macrolide-resistant BRD-associated bacteria (n = 101), msrE-mphE and/or erm42 were detected in 95% of cases using RPA. The remaining 98 samples were either culture-negative, or the recovered bacteria were macrolide-susceptible: 43% of these were RPA-positive for at least one macrolide ARG. Together with BC-AST and PCR, Bayesian latent class modelling estimated the clinical sensitivity of RPA for macrolide ARGs to be 95% and specificity to be 58%, with moderate agreement between RPA and BC-AST (κ = 0.52) or PCR (κ = 0.55). The estimated sensitivity of the RPA multiplex assay for the targeted macrolide ARGs was very good, although estimated specificity was limited. However, Sanger sequencing confirmed RPA detection of msrE-mphE in BC-AST/PCR-negative samples (n = 23), reflecting the presence of this locus in non-target bacteria, as well as potential ARG variants among BRD bacteria. These findings support the potential of RPA for rapid ARG detection from extracted DNA. Continued assay optimization and evaluation for detection of respiratory bacteria and ARGs will further enhance its diagnostic utility. 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

Mountain glaciers are sensitive indicators of climate variability, and their retreat since the end of the Little Ice Age (LIA) has strongly reshaped alpine environments worldwide. In the Greater Caucasus, glacier shrinkage has accelerated over the past century, yet detailed multi-temporal reconstructions remain limited for many glaciers. Here, we reconstruct the post-LIA evolution of Tsaneri–Nageba Glacier, one of largest ice bodies in the Georgian Caucasus, and document the development of its newly formed proglacial lake. Using a combination of geomorphological mapping, historical maps, multi-temporal satellite imagery, Uncrewed Aerial Vehicle (UAV) photogrammetry, and sonar bathymetry, we quantify glacier change from ~1820 to 2025 and provide the first direct measurements of a proglacial lake in the Tsaneri–Nageba system—and indeed in the Georgian Caucasus as a whole. Our results reveal that Tsaneri–Nageba Glacier has shrunk from ~48 km² at its LIA maximum to ~30.6 km² in 2025, a loss of −43.5% (or −0.21% yr⁻¹). The pace of shrinkage intensified after 2000, with the steepest losses recorded between 2014 and 2025. Terminus positions shifted up-valley by nearly 3.9 km (Tsaneri) and 4.3 km (Nageba), accompanied by fragmentation of the former compound valley glacier into smaller ice bodies. Long-term meteorological records confirm strong climatic forcing, with pronounced summer warming since the 1990s and declining winter precipitation. A proglacial lake started to form in mid-summer 2015, which by 03/09/15 had a surface area of ~14,366 m², expanding to ~106,945 m² by 10/07/2025. The lake is in contact with glacier ice and is thus prone to calving. It is dammed by unconsolidated moraines and bounded by steep, active slopes, making it susceptible to generating a glacial lake outburst flood (GLOF). By providing the first quantitative measurements of a proglacial lake in the region, this study establishes a baseline for future monitoring and risk assessment. The findings highlight the urgency of integrating glaciological, geomorphological, and hazard studies to support community safety and water resource planning in the Caucasus. Full article

Bovine respiratory disease is a significant health concern in dairy calves, impacting short-term growth and potentially long-term productivity. While previous studies have linked early-life lung consolidation, often subclinical and diagnosed by lung ultrasonography, to reduced preweaning average daily gain, its extended effects on production and reproductive parameters remain less studied, particularly in specific geographical contexts. This study presents a follow-up analysis on a cohort of dairy calves originally monitored weekly from birth to weaning for lung consolidation via TUS in an Iranian dairy herd. Two years post-weaning, comprehensive production and reproduction data were collected and analyzed for these same animals. Our objective was to investigate the long-term associations between early-life lung consolidation and subsequent outcomes, including mature equivalent milk yield, corrected milk yield, culling risk before and during lactation, age at first breeding, age at first calving, and reproduction parameters such as services per conception and conception rate (the percentage of cows or heifers that become pregnant after a single insemination or breeding attempt). Data analysis, employing descriptive statistics, survival analysis, and non-parametric tests, revealed that while early-life lung consolidation (defined by ≥1 cm or ≥3 cm depth, and number of episodes) did not show significant associations with culling probability or mature equivalent milk yield, interesting numerical trends were observed. The study highlights the complexities of establishing clear long-term links, suggesting that while subclinical BRD can have immediate growth impacts, its chronic effects on later production and reproduction may be subtle and require larger cohorts or more targeted analysis to achieve statistical significance. The findings reinforce the need for cautious interpretation of p-values in the context of multiple comparisons and underscore the challenges in quantifying long-term economic consequences of early-life respiratory health. Full article

Background/Objectives: Long-read metagenomic sequencing can detect bacteria and antimicrobial resistance genes (ARGs) from bovine respiratory samples, providing an alternative to culture and antimicrobial susceptibility testing (C/S). This study applied Bayesian latent class models (BLCMs) to estimate the sensitivity (Se) and specificity (Sp) of long-read metagenomic sequencing compared to C/S for detecting Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni, as well as associated macrolide and tetracycline resistance potential. Methods: Deep nasopharyngeal swabs were collected from fall-placed feedlot calves at arrival, 13, and 36 days on feed across two years and two metaphylaxis protocols. Samples underwent C/S and long-read metagenomic sequencing. BLCMs were used to estimate Se and Sp for the detection of bacteria and potential for antimicrobial resistance (AMR). Results: Se and Sp for detecting respiratory bacteria by metagenomics were not significantly different than culture, with four exceptions. For the 2020 samples, Se for M. haemolytica was lower than culture, and Sp for H. somni was lower, while in both 2020 and 2021 samples, Se for P. multocida was higher for metagenomics than culture. The estimated Se and Sp of metagenomics for the detection of msrE-mphE, EstT, and tet(H) within bacterial reads were either not significantly different or were lower than AST, with Sp > 95% with one exception. Conclusions: This study provided BLCM-based estimates of clinical Se and Sp of metagenomics and C/S without assuming a gold standard in a large pen research setting. These findings demonstrate the potential of long-read metagenomics to support bovine respiratory disease diagnostics, AMR surveillance, and antimicrobial stewardship in feedlot cattle. Full article

The purpose of this study was to evaluate the preventive effects of propylene glycol (PG) or sucrose (SC) in dairy cows with high levels of non-esterified fatty acids (NEFAs) during the close-up period. From July 2021 to August 2022, blood samples were collected from 193 cows between 14 and 7 days prior to the expected calving date in two farms, and 35 multiparous cows with serum NEFA ≥ 0.3 mEq/L were randomly assigned to PG (500 mL/day, n = 11), SC (1000 mL/day of 50% solution, n = 11), and untreated control (HC; n = 13) groups. Treatments were administered orally for 5 consecutive days. Compared with HC cows, the serum NEFA concentration tended to be lower in SC cows at 3 days in milk (DIM) and was significantly lower in PG cows at 14 DIM. Serum β-hydroxybutyrate concentrations tended to be lower in SC cows at 21 DIM. Blood glucose concentrations were higher in both treatment groups at 3 DIM, and the serum total bilirubin concentration remained lower until 14 DIM in PG cows and until 7 DIM in SC cows. At 7 DIM, PG cows showed significantly higher total very low-density lipoprotein levels and PG and SC cows had significantly or tendentially higher low-density lipoprotein triglyceride concentrations. Cows in both treatment groups had significantly reduced culling after calving. These results suggest that prophylactic administration of PG or SC improves energy metabolism by supporting liver function, thereby reducing postpartum culling, with the PG group showing a more consistent effect. Full article

This study compared serum immunological parameters, cytokines, intestinal permeability, fecal microbiota, and short-chain fatty acids (SCFAs) between healthy and diarrheic suckling calves. Serum and facecal samples were analyzed using ELISA kits, 16S rDNA sequencing, and targeted metabolomics. Compared with healthy calves, the serum levels of aspartate aminotransferase, interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), endotoxin (ET), and diamine oxidase (DAO) were significantly higher (p < 0.05), whereas the serum levels of immunoglobulin A (IgA), immunoglobulin G (IgG), and interleukin-10 (IL-10) were significantly lower in diarrheic calves (p < 0.05). The contents of propionic acid, butyric acid, and valeric acid significantly decreased in the fecal of diarrheic calves (p < 0.05). Moreover, the Chao1 and observed_features index of fecal microbiota significantly decreased in diarrheic calves (p < 0.05). The relative abundance of Escherichia-Shigella, Clostridium_sensu_stricto_1, and Streptococcus was significantly higher (p < 0.05), whereas Phascolarctobacterium, Ruminococcus torques group, and Faecalibacterium were significantly lower in diarrheic calves (p < 0.05). Escherichia-Shigella abundance was positively correlated with ET, DAO, IL-1β, and TNF-α levels (p < 0.05). Faecalibacterium abundance was significantly positively correlated with IgG, IgA, IL-10, and butyric acid but negatively correlated with ET and DAO levels (p < 0.05). In summary, diarrheic suckling calves exhibited reduced immune function, inflammatory response, and increased intestinal permeability. The relative abundance of fecal microbiota of Escherichia-Shigella and Clostridium_sensu_stricto_1 increased, while propionic acid, butyric acid, and valeric acid concentration were decreased in calves with diarrhea. This underscores the critical interplay between microbiota balance and gut health in diarrhea. Full article

Background/Objectives: Long-read metagenomic sequencing can assign antimicrobial resistance genes (ARGs) to speciated bacterial reads. This study evaluated whether metagenomic data from respiratory bacteria derived from feedlot calves sampled in the early feeding period were associated with subsequent bovine respiratory disease (BRD) treatment and phenotypic antimicrobial resistance (AMR) at treatment. Methods: Deep nasopharyngeal swabs (DNPSs) obtained at arrival processing (1 day on feed; DOF), 13 DOF, and the time of BRD treatment were cultured and subjected to antimicrobial susceptibility testing (AST) and long-read metagenomic sequencing. Analyses focused on macrolide (mphE-msrE, EstT) and tetracycline (tet(H)) ARGs within reads assigned to Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, or Bibersteinia trehalosi. Generalized estimating equations assessed associations between metagenomic results from 1 and 13 DOF and subsequent BRD treatment risk and AST outcomes at treatment, at both the individual animal (calf) and pen levels. Results: Calf-level detection of H. somni at 13 DOF was associated with a greater BRD treatment risk between 14 and 45 DOF. An increased pen prevalence of either M. haemolytica or P. multocida at 13 DOF was associated with a greater BRD treatment risk from 14 to 45 DOF. At 13 DOF, detections of mphE-msrE, EstT, or tet(H) in target bacteria were associated with corresponding phenotypic AMR at BRD treatment. Similarly, a higher pen-level prevalence of mphE-msrE or EstT at 13 DOF was also associated with increased macrolide resistance at BRD treatment. Conclusions: The results from long-read metagenomic sequencing of DNPSs collected at 13 DOF were associated with both BRD risk and AMR at treatment. These findings align with prior culture-based results and support the potential utility of pen-level metagenomic testing for AMR surveillance and informing antimicrobial selection in feedlots. Full article

This study aimed to characterize Mycoplasmosis bovis strain 16M—a highly virulent isolate from one Chinese outbreak—as a candidate for challenge models and inactivated vaccine development. We assessed strain 16M through morphological observation, PCR identification, drug susceptibility testing, growth titer and biofilm quantification, immunological profiling, and calf challenge experiments. We used genomic resequencing to evaluate the genetic stability across 150 passages. Classified as the prevalent ST52 lineage in China, strain 16M showed phylogenetic proximity to strain 08M and exhibited multidrug resistance (notably to macrolides). It achieved higher titers and stronger biofilm formation than other isolates and the reference strain PG45. In calves, intratracheal inoculation with 16M induced universal infection, severe pulmonary consolidation, and peribronchial cuffing, with significantly higher disease scores (p < 0.01). The inactivated 16M vaccine elicited elevated antigen-specific IgG titers, PBMC proliferation, and IFN-γ production versus PG45. Post challenge, immunized calves showed reduced pathological lesions, shorter bacterial shedding, and lower disease scores than the infected controls (p < 0.05). Genetic stability was confirmed for virulence-associated genes (e.g., adhesion proteins), with stable titers and biofilm production within 50 generations. Strain 16M combines high virulence for challenge modeling and industrial-scale vaccine suitability, owing to its robust growth, stable immunogenicity, and genetic consistency. Full article

The present study assessed the efficacy of selective dry cow therapy (SDCT) on two commercial Holstein-Friesian farms in the Czech Republic, involving 572 quarter milk samples from 74 cows collected over a two-year period. Quarter samples were taken both at dry-off (n = 296) and post-calving (n = 276) to assess somatic cell count (SCC), cultured microbial results (counts), milk composition, and mastitis incidence. The average SCC at dry-off was 264,000 cells/mL (SD = 650,000) in Farm 1 and 224,000 cells/mL in Farm 2. Mastitis incidence averaged 24.42% and 18.75% in Farms 1 and 2, respectively. Correlation analysis revealed significant associations between pre-dry-off milk parameters and post-calving udder health indicators, including negative correlations between SCC prior to drying-off and lactose content after calving (r = −0.161, p < 0.01). Statistical analyses showed a significant farm effect on cultured microbial occurrence and mastitis occurrence after calving (p < 0.05), as well as a significant influence of lactation number on postpartum mastitis and SCC (p < 0.05). Also, mastitis incidence was significantly higher (9.43%, p < 0.05) in treated quarters. The use of selective non-antibiotic dry cow therapy does not impair udder health and milk quality but helps reduce the risk of antibiotic resistance. Further refinement of diagnostic criteria is needed to optimize treatment decisions and improve herd-level outcomes. Full article

Background/Objectives: Calves have immature immune systems, hence immunization with vaccines is essential to protect them from infectious diseases. However, immune responses to vaccines vary widely among individuals. Therefore, strategies for enhancing vaccine efficacy are needed, particularly those targeting low responders to vaccines. Probiotics have attracted attention because of their beneficial immunomodulatory effects on the host. Although probiotics may improve calf immunity, their potential to enhance immune responses to vaccines in calves remains unclear. Thus, we investigated whether immune responses to vaccines, especially T-cell responses, are enhanced when calves receive a combination of probiotic supplementation and vaccination. Methods: Calves were divided into three feeding groups, as follows: negative control feed, live bacteria-mixed feed (Zeosapo KB), and Clostridium butyricum-only feed (CB). After weaning, all calves received two doses of a live attenuated hexavalent viral vaccine. T-cell responses to a vaccine antigen were evaluated by measuring the expression levels of lymphocyte activation markers CD25 and CD69, as well as Th1 cytokine production, in peripheral blood mononuclear cell culture assays. Results: CD25 expression significantly increased in CD4⁺ T cells four weeks after the booster vaccination in the Zeosapo KB- and CB-fed groups. In addition, the CD25⁺CD69⁺ cell ratio in CD4⁺ T cells was increased in these groups. The production of Th1 cytokines in the culture supernatant was also increased in the CB-fed group. Conclusions: This clinical study demonstrates that probiotics activate CD4⁺ T cells and enhance Th1 cytokine responses in vaccinated calves. Full article

Background/Objectives: The aim of this study was to classify cows with respect to different diets, dry period (DP) lengths, and lactation weeks based on body weight, milk variables, and plasma metabolites measured in early lactation. Methods: Holstein–Friesian cows (n = 95) were randomly assigned to three DP lengths (0, 30, or 60 d; n = 31, 34, and 30) and two early-lactation diets (lipogenic: n = 47; glucogenic: n = 48) in a 3 × 2 factorial design. From 10 d pre-calving to 8 weeks postpartum, cows received experimental diets. An XGBoost model was trained for classification using weekly body weight, milk variables, and plasma metabolites, validated via 1000 repeated hold-out partitions with stratified sampling. Results: Classification performance for lactation week, relative to week 1 in lactation, was good, with an area under the curve (AUC) > 0.9, independent of diet or DP length. The classification for 0 d vs. 60 d DP length was better than that for 0 d vs. 30 d or 30 d vs. 60 d DP length, showing an AUC > 0.8, independent of diet or lactation week. The top features to classify diet were plasma urea and milk fat content. Milk yield and protein content were the important features for classifying lactation weeks regardless of diet, while milk fat content was a critical predictor specific to the glucogenic diet. Conclusions: Our findings demonstrate that milk and plasma features can retrospectively classify management groups in early lactation using machine learning approaches. Full article

Nutritional and cooling strategies to abate the negative effects of heat stress during the dry period have been used to improve the performance of dairy cattle. The objective of this study was to evaluate the effects of feeding an immunomodulatory supplement (OmniGen-AF^®, OMN) before, during, and after exposure to either heat stress or active cooling during the dry period on immune function and mammary development in dairy cows. During late lactation (at least 60 d before dry off), cows were provided with evaporative cooling systems (shade, fans, and soakers) and assigned to two groups: placebo (56 g/d of AB20^® top-dressed; CON) or OmniGen-AF^® (OMN, 56 g/d top-dressed). Cows were dried off ~46 d before the expected calving date and further split into evaporative cooling (shade, fans, and soakers; CL) or heat stress (only shade; HT) pens. Thus, after dry off, there were four treatment groups: heat stress with placebo (HT, n = 17), HT with OMN supplementation (HT + OMN, n = 19), CL with placebo (CL, n = 16), and CL with OMN supplementation (CL + OMN, n = 11). From a subset of cows (n = 6–8 per group), four blood samples were collected during the dry period (−43, −39, −32, and −21 d relative to calving) to evaluate neutrophil function and blood hematology. In addition, mammary biopsies (4–6 cows/treatment) were collected at −43, −39, −32, and −21 d relative to calving to evaluate mammary gland gene expression and histology, i.e., Tdt dUTP nick-end labeling (TUNEL) and Ki67. Genes related to autophagy, apoptosis, and cell proliferation were analyzed by qRT-PCR. Relative to CL, HT downregulated the expression of beclin-2 (BECN2) but upregulated the expression of beclin-1 (BECN1) on days −43 and −39 relative to calving, respectively. Also, relative to CL, HT upregulated the expression of BAX and FAS on day −39 relative to calving. These differences in gene expression were followed by HT cows having a lower total cell apoptosis rate during involution relative to CL cows. Further to these effects, HT leads to a lower alveoli number relative to CL cows. As in the CL treatment, OMN cows have a higher total cell apoptosis rate and alveoli number relative to CON cows. In addition, OMN cows have higher total cell proliferation relative to CON. Prolactin (PRL) and cortisol concentrations were evaluated during the dry period at days −45, −26, −3, and −1 relative to calving. Relative to CL, HT cows had higher PRL at day −45 but lower PRL on day −1 relative to calving, and a similar trend was observed for cortisol concentrations. In summary, HT impacts mammary gland gene expression, compromises mammary involution, reduces alveoli number, and alters hormone dynamics throughout the dry period. Following the same trends as the CL treatment, OMN increases mammary gland turnover by having a higher cell apoptosis and cell proliferation rate and lower connective tissue relative to CON cows. Full article

This study aimed to evaluate blood lactate, anion gap, and ionised calcium levels as potential diagnostic biomarkers in calves with atresia coli, and to identify possible predisposing factors such as breed, gender, age, method of conception, number of lactations, and births. The study included twenty-two calves with atresia coli and ten healthy controls, all aged 1–11 days (median, 3 days), brought to Erciyes University Veterinary Faculty from Kayseri and nearby provinces due to non-defecation and abdominal swelling. Prominent clinical findings among the 22 calves with atresia coli included abdominal distension in 90.9%, anorexia in 81.8%, and depressed general posture in 86.4%. Blood gas analysis revealed significantly elevated lactate and anion gap and decreased ionised calcium and pH in atresia coli calves compared to controls (p < 0.05). Anion gap (>14.05 mmol/L) and ionised calcium (<1.205 mmol/L) demonstrated high diagnostic accuracy (AUC: 0.964 and 0.872, respectively), suggesting their potential as supportive biomarkers for early detection of atresia coli. The study data revealed that male gender, artificial insemination, and calves born from the third or subsequent pregnancies are statistically significant risk factors for the development of atresia coli. Atresia coli in calves is characterized by specific clinical signs and significant changes in blood gas parameters, such as elevated lactate and anion gap and reduced ionised calcium and pH. Early detection using these markers can improve diagnosis, and further studies should focus on prevention by addressing these risk factors. Full article