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Background: Long-distance road transportation is a common practice in the beef industry, frequently resulting in bovine respiratory disease (BRD) and compromised growth performance. However, a comprehensive investigation integrating clinical performance, physiological conditions, and nasopharyngeal microflora remains lacking., Methods: This study aimed to evaluate the respiratory health and immunometabolic status of 54 beef calves subjected to a 3000-km journey. The respiratory health of calves was monitored over 60 days post-arrival using a modified clinical scoring system. Nasopharyngeal microflora and venous blood samples were collected at 3 time points: before transportation (A), 30 days post-arrival (B), and 60 days post-arrival (C), for 16S rRNA microbiomics, whole-blood transcriptomics, serum metabolomics, and laboratory assays., Result: Within the first week post-arrival, the appetite and mental scores of calves dropped to zero, while other respiratory-related scores progressively declined over the 60 days. The α-diversity of nasopharyngeal microflora in calves was similar at time points A and B, both significantly higher than at time point C. The structure of these microbial communities varied significantly across different time points, with a notably higher relative abundance of BRD-related genera, such as Pasteurella and Mannheimia, detected at time point A compared to B and C. The composition and gene expression profiles of circulating blood cells at time point A were significantly different from those at B and C. Specifically, higher expression levels of oxidative- and inflammatory-related genes, cytokines, and enzymes were observed at time point A compared to B and C. Higher levels of catabolism-related metabolites and enzymes were detected at time point A, while higher levels of anabolism-related metabolites and enzymes were observed at time points B and C. Additionally, significant correlations were found among microorganisms, genes, and metabolites with differing abundances, expression levels, and concentrations across time points. Stronger correlations were observed between calves' performance and nasopharyngeal microflora and immunometabolic status at time point A compared to B or C., Conclusions: Collectively, these results confirm that 3000 km of road transportation significantly alters the composition and gene expression profiles of circulating white blood cells in calves, affects their metabolic processes, disrupts the balance of the respiratory microbial community, and leads to pronounced respiratory symptoms that persist for at least 60 days. During this period, the influenced composition and gene expression of circulating blood cells, metabolic processes, and nasopharyngeal microbial community gradually return to equilibrium, and the respiratory symptoms gradually diminish. This observational research indicates that transportation induces BRD in calves by disrupting the homeostasis of their immune function, metabolic processes, and nasopharyngeal microbial community. However, these results and their underlying molecular mechanisms warrant further validation through well-designed in vivo and in vitro confirmatory experiments with larger sample size. Video Abstract., Competing Interests: Declarations Ethics approval and consent to participate This experiment received approval from the Institutional Animal Care and Use Committee of Sichuan Agricultural University (Approval Code: 2021103003; Approval Date: September 5, 2022), following the Regulations for the Administration of Affairs Concerning Experimental Animals issued by the State Science and Technology Commission of China. Veterinarians from the Caijiashan Breeding Company, an intensive beef cattle breeding facility in Quxian County, Dazhou, Sichuan Province, supervised all the experimental procedures. Consent for publication All authors have consented to the publication of this work. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

The monitoring of pre-weaned calf behavior is crucial for ensuring health, welfare, and optimal growth. This study aimed to develop and validate a machine learning-based technique for the simultaneous monitoring of multiple behaviors in pre-weaned beef calves within a cow-calf contact (CCC) system using collar-mounted sensors integrating accelerometers and gyroscopes. Three complementary models were developed to classify feeding-related behaviors (natural suckling, feeding, rumination, and others), postural states (lying and standing), and coughing events. Sensor data, including tri-axial acceleration and tri-axial angular velocity, along with video recordings, were collected from 78 beef calves across two farms. The LightGBM algorithm was employed for behavior classification, and model performance was evaluated using a confusion matrix, the area under the receiver operating characteristic curve (AUC-ROC), and Pearson's correlation coefficient (r). Model 1 achieved a high performance in recognizing natural suckling (accuracy: 99.10%; F1 score: 96.88%; AUC-ROC: 0.999; r: 0.997), rumination (accuracy: 97.36%; F1 score: 95.07%; AUC-ROC: 0.995; r: 0.990), and feeding (accuracy: 95.76%; F1 score: 91.89%; AUC-ROC: 0.990; r: 0.987). Model 2 exhibited an excellent classification of lying (accuracy: 97.98%; F1 score: 98.45%; AUC-ROC: 0.989; r: 0.982) and standing (accuracy: 97.98%; F1 score: 97.11%; AUC-ROC: 0.989; r: 0.983). Model 3 achieved a reasonable performance in recognizing coughing events (accuracy: 88.88%; F1 score: 78.61%; AUC-ROC: 0.942; r: 0.969). This study demonstrates the potential of machine learning and collar-mounted sensors for monitoring multiple behaviors in calves, providing a valuable tool for optimizing production management and early disease detection in the CCC system.

This experiment evaluated the effects of multiple bovine-appeasing substance (BAS) administration during a 42-d preconditioning program followed by a feedlot receiving period on productivity, health, and physiological variables of feeder cattle. Ninety calves were weaned, weighed, loaded into a livestock trailer, transported for 70 km, and unloaded at the Bozeman Agricultural Research and Teaching Farm for a 42-d preconditioning program. Upon arrival, calf body weight (BW) was recorded again, and both pre- and post-transport BWs were averaged and used as calf weaning initial BW. Calves were ranked by BW, sex, and age in a completely randomized design and assigned to receive 1) multiple administrations of BAS at weaning (day 0), days 14, 28, and before transport and feedlot entry (day 42; BAS; RSEA Group, Quartier Salignan, France; n = 9 pens/treatment), or 2) placebo (diethylene glycol monoethyl ether; CON; n = 9 pens/treatment). Treatments (5 mL) were applied to the nuchal skin area of each animal during the preconditioning period. Calves within treatment groups were ranked again by initial BW, sex, and age, in a manner that pens have similar initial BW, age, and three steers and two heifers and allocated to 1 of the18 drylot pens. On day 42, calves were combined within the treatment group, loaded into two different single double-deck commercial livestock trailers, and transported for 1,000 km (approximately 16 h). Upon arrival (day 43), calves were unloaded at the same feedyard. Blood samples were collected on days 0, 3, 7, 14, 21, 28, 42, 43, 46, 50, 57, 64, and 90. Average daily gain, final BW, and feed efficiency did not differ (P > 0.52) between BAS and CON calves in the preconditioning and receiving phases. A treatment × day interaction was detected (P < 0.001) for plasma haptoglobin concentrations, which was greater (P < 0.01) in CON on days 3 and 7 vs. BAS calves. During the preconditioning phase, serum NEFA concentration was reduced (P < 0.01) in BAS on day 3 compared with CON calves. A treatment × day interaction was detected (P = 0.001) for exit velocity, which was greater (P < 0.001) for CON vs. BAS calves on days 3, 7, 14, and 21 during the preconditioning phase and on day 46 of the receiving phase. Therefore, Applications of BAS reduced immunological responses and exit velocity associated with stress caused by management practices, but did not improve performance during the preconditioning and receiving phases., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Fall-calving primiparous beef females [body weight (BW): 451 ± 28 (SD) kg; body condition score (BCS): 5.4 ± 0.7] were individually-fed 100% (control; CON; n = 13) or 70% (nutrient restricted; NR; n = 13) of estimated metabolizable energy and metabolizable protein requirements from day 160 of gestation to calving. Post-calving, all dams were individually-fed tall fescue hay supplemented to meet estimated nutrient requirements for maintenance, growth, and lactation in Calan gates until day 149 of lactation, which limited calves to milk only. From day 150 of lactation until weaning at day 243, dams and calves were group-fed in drylots. Dam BW and metabolic status were determined every 21 d, and BCS and backfat (BF) were determined every 42 d of lactation until weaning. Pre-weaning calf BW, size, and metabolic status were determined every 21 d. Data were analyzed with nutritional plane, calving date, and calf sex (when P < 0.25) as fixed effects. Circulating metabolites included day and nutritional plane × day as repeated measures. We previously reported that post-calving, NR dams were 64 kg and 2.0 BCS less than CON, but calf BW and size at birth were not affected. During the first 147 d of lactation, NR dams gained more (P < 0.01) BW than CON and increased (P < 0.01) BCS, while CON decreased (P ≤ 0.01) BCS and BF. Previously, NR dams had lower (P < 0.01) circulating triglycerides on day 1 of lactation, tended to have lower (P = 0.08) triglycerides on day 21, and had lower (P ≤ 0.04) non-esterified fatty acids (NEFA) on days 21 and 243 than CON. Maternal glucose and urea N were not affected (P ≥ 0.73). At weaning, NR dams weighed 17 kg less (P = 0.15), were 0.67 BCS lower (P < 0.01), and tended to have less (P = 0.06) BF. Calves born to NR dams weighed less (P = 0.02) than CON by day 42 of age and were 13% smaller (P < 0.01) at weaning. Calf girth measures diverged (P ≤ 0.05) by day 21 of age, and skeletal size measures were less (P ≤ 0.08) for calves born to NR dams at most timepoints after day 63 of age. Calves born to NR dams tended to have lower (P = 0.09) circulating urea N pre-weaning than CON, but glucose, triglycerides, and NEFA were not affected (P ≥ 0.16). In summary, first-parity beef females that were nutrient restricted during late gestation experienced compensatory growth and gained body condition during lactation but were still thinner at weaning. Nutrient restriction reduced pre-weaning calf growth, likely due to decreased milk production., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.)

The association of poor transfer of passive immunity (TPI) with negative health outcomes is extensively researched in dairy calves. However, few field studies have examined the effect of total and particularly pathogen-specific Immunoglobulin G (IgG) concentrations on pre-weaning health and growth of beef calves. Hence, the objective of this study was to determine the association of total and pathogen-specific IgG concentrations against selected pathogens associated with neonatal calf diarrhea (NCD) and bovine respiratory disease (BRD) and the odds of pre-weaning treatments, mortality, and the growth of newborn beef calves. A total of 420 serum samples from 1- to 7-day old beef calves born on 6 farms in Alberta, Canada, were available for this observational study. Serum samples were analyzed by radial immunodiffusion for total IgG concentration and by enzyme-linked immunosorbent assays for pathogen-specific IgG concentrations against Escherichia coli (E. coli), bovine Rotavirus (BRoV), Cryptosporidium parvum (C. parvum), Bovine Viral Diarrhea Virus (BVDV), Parainfluenza Virus Type 3 (PI-3), Bovine Respiratory Syncytial Virus (BRSV), and Bovine Herpesvirus Type 1 (BHV-1). Data about the individual dam- and calf-level risk factors, calf treatments, mortality, and birth and weaning weights were collected. Multivariable multilevel logistic and linear regression models were built to evaluate the association of total and pathogen-specific IgG concentrations with the odds of mortality and average daily gain (ADG), respectively, while their association with the odds of pre-weaning treatment was established by univariable logistic regression analysis. The odds of calves with IgG concentrations < 10 g/L of getting treated (OR 7.9, 95 % CI 2.7-23.7) and dying (OR: 18.5, 95 % CI: 3.7-93.4) were higher than for their counterparts (P < 0.0001). Calves with IgG concentrations < 24 g/L also had higher odds of dying (OR: 10.1, 95 % CI: 2.6-40.2) and had lower ADG (-0.09 kg, SE: 0.03, P < 0.002) than calves with IgG concentrations ≥ 24 g/L. Higher BVDV-specific IgG concentration was protective against mortality (OR: 0.97, 95 % CI: 0.96-0.99, P < 0.001). This study highlights the negative association of inadequate TPI with health and growth of beef calves and thus, the need to refine protocols for dam vaccination and colostrum intervention in cow-calf operations to meet these higher IgG targets., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Published by Elsevier B.V.)

Bovine papular stomatitis (BPS) generally is a mild viral disease caused by the Bovine papular stomatitis virus (BPSV) belonging to the genus Parapoxvirus (PPV). This study aimed to perform the first molecular characterization and phylogenetic analysis of BPSV in beef calves in Iran. Clinical examinations were carried out on four beef cattle herds in West Azerbaijan province, which had experienced outbreaks of papular lesions. Fifty swab samples were collected from the papular lesions on the muzzle, lips, and oral cavity of affected calves, and after viral DNA extraction, they were subjected to polymerase chain reaction (PCR). The results of PCR confirmed the presence of BPSV in all calves with clinical symptoms. The partial B2L gene was sequenced based on nucleotides, and phylogenetic analysis was performed using MEGA 11.0.13. The analysis revealed that BPSV isolates from beef calves in Iran formed two clades. Clade 1 exhibited similarities to the isolates from Finland, Japan, and Georgia, while Clade 2 was similar to the Zambian isolates. These findings indicate the presence of genetic diversity and potential variability within the virus population. Further studies with larger sample sizes and diverse geographic regions will increase the resolution of the phylogenetic tree and contribute to a comprehensive understanding of how BPSV circulates in the country., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: A close connection between a protozoan parasite and the balance of the other gut microbes of the host has been demonstrated. The calves may be naturally co-infected with many parasites, and the co-effects of parasites on other intestinal microbes of calves remain unclear. This study aims to preliminarily reveal the relationship between intestinal parasites and other intestinal microbes in calves., Methods: Fecal samples were collected from four calves with bloody diarrhea, four calves with watery diarrhea, and seven normal calves, and the microbial flora of the samples were analyzed by whole-genome sequencing. Protozoal parasites were detected in the metagenome sequences and identified using polymerase chain reaction (PCR)., Results: Cryptosporidium, Eimeria, Giardia, Blastocystis, and Entamoeba were detected by metagenomic analysis, and the identified species were Giardia duodenalis assemblage E, Cryptosporidium bovis, Cryptosporidium ryanae, Eimeria bovis, Eimeria subspherica, Entamoeba bovis, and Blastocystis ST2 and ST10. Metagenomic analysis showed that the intestinal microbes of calves with diarrhea were disordered, especially in calves with bloody diarrhea. Furthermore, different parasites show distinct relationships with the intestinal microecology. Cryptosporidium, Eimeria, and Giardia were negatively correlated with various intestinal bacteria but positively correlated with some fungi. However, Blastocystis and Entamoeba were positively associated with other gut microbes. Twenty-seven biomarkers not only were significantly enriched in bloody diarrhea, watery diarrhea, and normal calves but were also associated with Eimeria, Cryptosporidium, and Giardia. Only Eimeria showed a distinct relationship with seven genera of bacteria, which were significantly enriched in the healthy calves. All 18 genera of fungi were positively correlated with Cryptosporidium, Eimeria, and Giardia, which were also significantly enriched in calves with bloody diarrhea. Functional genes related to parasites and diseases were found mainly in fungi., Conclusions: This study revealed the relationship between intestinal protozoan parasites and the other calf gut microbiome. Different intestinal protozoan parasites have diametrically opposite effects on other gut microecology, which not only affects bacteria in the gut, but also is significantly related to fungi and archaea., (© 2023. The Author(s).)

The aim of the present study was to compare the predictive performance of decision trees, artificial neural networks, and logistic regression used for the classification of daily body weight gains in beef calves. A total of 680 pure-breed Simmental and 373 Limousin cows from the largest farm in the West Pomeranian Province, whose calves were fattened between 2014 and 2016, were included in the study. Pre-weaning daily body weight gains were divided into two categories: A-equal to or lower than the weighted mean for each breed and sex and B-higher than the mean. Models were developed separately for each breed. Sensitivity, specificity, accuracy, and area under the curve on a test set for the best model (random forest) were 0.83, 0.67, 0.76, and 0.82 and 0.68, 0.86, 0.78, and 0.81 for the Limousin and Simmental breeds, respectively. The most important predictors were daily weight gains of the dam when she was a calf, daily weight gains of the first calf, sex of the third calf, milk yield at first lactation, birth weight of the third calf, dam birth weight, dam hip height, and second calving season. The selected machine learning models can be used quite effectively for the classification of calves based on their daily weight gains.

Background: Little is known about the effects of trace mineral supplementation on the stress response in beef calves., Objectives: To investigate the effect of injectable trace mineral supplementation (ITM) on the stress response in beef calves exposed to different types of stress., Animals: Thirty weaned Angus and Angus crossbred calves., Methods: The enrolled calves were randomly assigned to 2 groups: ITM, 15 calves received modified-live virus vaccine (MLV) and ITM SC and 15 calves received MLV and saline SC (CONT). The calves were exposed to 3 types of stress: the stress of MLV vaccination (d0), nasal aerosol with bovine viral diarrhea virus-2 (BVDV-2) challenge (d5), and liver biopsy (d26). The calves' body weights and health status were monitored. Leukocyte counts, serum cortisol concentration ([cort]), BVDV-2 serum neutralizing antibodies (SNA), and percentages of CD4 + , CD8 + , WC1 + , and CD25 + T-lymphocytes were measured., Results: Serum cortisol concentration ([cort]) showed strong associations with the percentage of CD8 + (r s  = .50), BVDV2-SNA (r s  = -.43), and WC1CD25 + (r s  = .41) cells, and rectal temperature (r s  = .40). The highest [cort] was reported 3 days after aerosol BVDV-2 challenge. Serum [cort] was decreased in ITM-treated calves 3 days post-BVDV-2 challenge, compared with CONT calves, with an average decrease of 18.5 ng/μL (95% confidence interval [CI], -6.07 to -31.3). The ITM-treated calves were heavier and healthier (P < .01) than the CONT calves., Conclusions and Clinical Importance: Trace mineral supplementation appears to have stress mitigation effects in beef cattle that may reflect positively on growth and health performance. Viral exposure is associated with a high degree of stress, which is considered a major welfare concern., (© 2023 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Background: Assessing the inadequate transfer of passive immunity (ITPI) in beef calves is crucial because calves with ITPI are at high risk for morbidity and mortality., Objectives: The aim of this study was to determine the accuracy of digital Brix (D-BRIX) and digital serum total protein (D-STP) refractometers to estimate different passive immunity status in beef calves and to determine the robustness of thresholds., Methods: Blood samples were collected from 202 (1-7 days old) beef calves. Serum total solid percentages, total protein concentrations, and IgG concentrations were measured with the D-BRIX refractometer, D-STP refractometer, and gold standard radial immunodiffusion (RID) assay, respectively. Data were analyzed using diagnostic test accuracy, areas under the receiver operating characteristics curve, Cohen's kappa coefficient, and misclassification costs analysis to estimate IgG concentrations <10, <16, and <24 mg/mL., Results: For the prediction of serum IgG concentrations <10, <16 and <24 mg/mL, the optimal cut-off values were determined to be <8.5% (Se: 100.0% (95% CI: 87.9-100.0); Sp: 94.2% [95% CI: 89.6-97.2]), <8.5% (Se: 92.1% [95% CI: 78.6-98.2]; Sp: 97.6% [95% CI: 93.9-99.3]), and <10.1% (Se: 88.8% [95% CI: 79.7-94.7]; Sp: 67.2% [95% CI: 58.1-75.4]), respectively, for the D-BRIX refractometer; and <5.2 g/dL (Se: 100.0% [95% CI: 87.9-100.0]; Sp: 93.6% [95% CI: 88.9-96.8]), <5.2 g/dL (Se: 92.1% [95% CI: 78.6-98.2]; Sp: 97.0% [95% CI: 93.0-99.0]), and <6.4 g/dL (Se: 87.5% [95% CI: 78.2-93.8]; Sp: 69.7% [95% CI: 60.7-77.7]), respectively, for the D-STP refractometer., Conclusions: The digital Brix and digital serum total protein refractometers can be used as monitoring tools for assessing passive immunity transfer in neonatal beef calves., (© 2022 American Society for Veterinary Clinical Pathology.)

In order to examine the effects of vaccine type and timing of crossbred beef calves ( n = 151) were assigned to one of three BRD vaccination protocols stratified by breed of sire, sex, and date of birth, which included: (1) KM-a pentavalent killed viral (KV) vaccine at 2 to 3 months of age (D 0) and a pentavalent modified-live viral (MLV) vaccine at weaning (D 127); (2) MM-MLV on D 0 and revaccinated on D 127 or (3) WN-MLV at weaning and D 140. Vaccination treatment did not affect performance nor BRSV serum-neutralizing antibody titers. Serum-neutralizing antibody titers to BVDV-1 were greatest for the MM through D 154. However, following booster (KM) or initial vaccination (WN) at D 127, titers increased for the other treatment groups to higher values (KM) by the end of the study. Delay of initial vaccination until weaning may have delayed specific antibody response in the WN group and skewed the immune response towards a Th-1 or cell-mediated response. Overall, the inclusion of an MLV in the vaccine protocol resulted in a more robust antibody response, and the timing of vaccination may affect the onset of efficacious and robust vaccine responses.

The purpose of this study was to investigate the antibody response to the bovine ephemeral fever virus (BEFV) vaccine in Japanese Black calves. Twenty-eight Japanese Black calves, which were raised on an ordinal farm, were divided into two groups. Fifteen calves received the inactivated BEFV vaccine at 12 and 16 weeks of age (vaccination group), and 13 calves did not receive the vaccine (non-vaccination group). Blood samples were obtained at 0, 4, 8, 12, 16, 20, 24, 28, and 32 weeks of age. As the results, in the vaccination group, the antibody titers at 16, 20, 24, 28, and 32 weeks of age were significantly higher than those at 0, 4, 8, and 12 weeks of age (p < 0.01). Additionally, antibody titer in the vaccination group increased after 16 weeks of age and showed a significantly higher level than that in the non-vaccination group throughout the remaining experimental period (p < 0.01). These results might be helpful in establishing a vaccination program against BEFV in calves., (© 2023 Japanese Society of Animal Science.)

Radial immunodiffusion (RID) is used to quantify IgG concentration in neonatal beef or dairy calf serum; variability has been noted that may affect the precision and accuracy of assay results. We determined the source, range, and homogeneity of variance in the results of a commercial bovine IgG RID assay (Triple J Farm). To estimate the variance in the precipitin ring diameter, we used 6 sera, measured 28 times across 8 plates and 4 lots, and 3 standards with known IgG concentrations, measured 75 times across 69 plates and 5 lots. The source of diameter variance was determined using variance partition coefficients for lot, plate, and repetition. We used 11 different methods to generate standard curves to convert RID precipitin ring diameters to IgG concentrations. The Levene test of homogeneity of variance (α = 0.1) was used to evaluate the equality of variance between the standards or serum precipitin ring diameters and calculated IgG concentrations. Lot and plate contributed minimally to the diameter variance. Precipitin ring diameters had equal variance. Calculated IgG concentrations for serum not requiring dilution had equal variance. A linear equation from aggregated standards, performed within the same day, had greater accuracy for the calculated IgG concentrations of the standards compared to other equation methods. Regardless of standard curve methodology or IgG concentration, variability inherent to the assay limits its clinical usefulness.

Bovine respiratory disease (BRD), calf diarrhea (CD), and navel infections are the most commonly reported diseases of western Canadian beef calves. The objectives of this study were to estimate the frequency of treatment for these diseases for specific age cohorts and identify potential opportunities for reducing antimicrobial use. Producers representing 89 western Canadian cow-calf herds completed a survey describing calfhood diseases and management. The most common reason for calf treatment before weaning was BRD (4.9%), and BRD treatment was described in 51% of reporting herds before 2 months of age. Calf diarrhea (2.9%) and navel infection (2.0%) were the second and third most common reasons for treatment. Most calves were treated for CD between 6 days and 1 month of age. Almost one in five herds reported routinely administering antimicrobials at birth. Calving heifers and cows together were all associated with an increased treatment risk for BRD in calves from birth to 2 months (OR 3.55, 95%CI 2.13-5.94, P < 0.0001), CD from 1 month to weaning (OR 3.94, 95%CI 1.29-12.0, P = 0.02), and navel infection (OR 4.55, 95%CI 1.78-11.6, P = 0.002). Failure to sort cow-calf pairs out of the calving area was also associated with an increased treatment risk for BRD from 4 months to weaning (OR 4.89, 95%CI 1.96-12.2, P = 0.0006) and CD from 24 h to 5 days (OR 2.82, 95%CI 1.03-7.75, P = 0.04), and not using the Sandhills system was associated with an increased treatment risk for navel infection (OR 4.55, 95%CI 1.78-11.6, P = 0.002). Other potentially modifiable factors associated with an increased risk of BRD in calves from birth to 2 months were winter feeding and calving in one area ( P < 0.0001), heifers calving in a higher density area ( P = 0.01), and an increasing number of times cow-calf pairs were gathered before turn out to summer pasture ( P = 0.0005). The purchase of any cows during the calving or prebreeding period was associated with an increased risk of BRD from birth to 2 months ( P < 0.0001) and from 2 to 4 months ( P < 0.0001). A history of respiratory bacterin vaccines administered to the dams was associated with a decreased risk of BRD in calves from 4 months to weaning ( P = 0.01). Cows calving in a higher density area was associated with an increased risk of CD from 1 month to weaning ( P = 0.02). These practices present opportunities for investigation of approaches to disease management that could support the judicious use of antimicrobials., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society of Animal Science.)

This study evaluated the effects of three different anthelmintic strategies on animal performance and anthelmintic effectiveness in weaned calves during a 42-d preconditioning period. The study was conducted at four locations over 2 yr and included a total of 797 recently weaned spring-born calves (initial BW 260 ± 37.7 kg). At the start of each year, at each location, calves were weaned and randomly assigned to one of four treatments: 1) oxfendazole ( ORAL ); 2) transdermal eprinomectin ( POUR ); 3) both anthelmintic treatments ( BOTH ); and 4) the control ( CONT ) group who did not receive treatment. Anthelmintic was applied per the manufacturer recommendation, the transdermal eprinomectin was administered at 1 mL per 10 kg and oxfendazole was administered orally at 1 mL per 50 kg. Weights were measured at the start of the study (day 0) and again at the end of the preconditioning phase (day 42). Fecal samples were collected at the start of the study prior to treatment application (day 0) and again on day 14. Rumen fluid was collected at the start of the study prior to treatment (day 0) and again on day 6. There were treatment effects for all performance metrics ( P < 0.001). All treatments had greater weight gain and value of weight gained ( P < 0.024), and all three strategies did not differ from each other ( P > 0.420). On day 0, there were no ( P = 0.795) treatment effects detected for fecal eggs per gram ( EPG ) counts. On day 14, there were ( P < 0.001) treatment effects for EPG counts with feces from CONT calves containing greater ( P < 0.014) EPG than feces from treated calves. EPG in feces from BOTH calves did not differ ( P > 0.123) from the other two treated groups and feces from POUR calves tended ( P = 0.052) to contain greater EPG counts than feces from ORAL calves. Volatile fatty acids were similar across treatments on days 0 and 6 ( P > 0.115). Butyrate tended ( P = 0.063) to be lower in ORAL on day 6. These results suggest that using eprinomectin and oxfendazole in combination was an effective strategy for reducing EPG and improving performance during a 42-d preconditioning phase., (Published by Oxford University Press for the American Society of Animal Science 2022.)

The aim of the current study was to assess the diagnostic characteristics of radial immunodiffusion (RID), capillary electrophoresis (CE) and digital brix refractometry (Bx) for the diagnosis of failure of passive transfer (FPT) of immunity in neonatal Belgian Blue beef calves in the absence of a gold standard using a Bayesian latent class model. Belgian blue beef calves (n = 202) from a large farm in the south of Belgium were blood-sampled at 48-72 h of age and tested for FPT. The true prevalence of FPT in this population of calves was 34.5 % (95 % BCI: 26.1-44.3) using a FPT cut-off point of 10 g IgG/L. This true prevalence increased to 66.3 (95 % BCI: 56.9-74.8) and 88.9 % (95 % BCI: 83.1-93.2) at FPT cut-off points of respectively 18 and 25 g IgG/L serum. The Bland-Altman plot comparing the RID and CE methods, revealed that the serum IgG concentrations obtained by RID were on average 2.25 (95 % CI 1.62-2.88) g/L higher than those measured by CE. Optimal cut-off values for CE, corresponding to the FPT values as measured by RID of 10, 18, and 25 g IgG/L serum, were respectively 10, 15, and 20 g IgG/L. The overall diagnostic accuracy of the three diagnostic tests was comparable at the FPT cut-off point of 10 g IgG/L serum (i.e. 85 %). At higher cut-off points for FPT, the RID and CE assays presumably performed better that the Bx method. In conclusion, we demonstrated that: (1) the CE method is a good alternative for the RID assay, the latter having important constraints when considering its practicality, and (2) the Bx method is a cheap and user-friendly indirect method to evaluate the FPT in new-born Belgian Blue beef calves., (Copyright © 2022. Published by Elsevier B.V.)

The impact of preweaning vaccination for bovine respiratory viruses on cattle health and subsequent bovine respiratory disease morbidity has been widely studied yet questions remain regarding the impact of these vaccines on host response and gene expression. Six randomly selected calves were vaccinated twice preweaning (T1 and T3) with a modified live vaccine for respiratory pathogens and 6 randomly selected calves were left unvaccinated. Whole blood samples were taken at first vaccination (T1), seven days later (T2), at revaccination and castration (T3), and at weaning (T4), and utilized for RNA isolation and sequencing. Serum from T3 and T4 was analyzed for antibodies to BRSV, BVDV1a, and BHV1. Sequenced RNA for all 48 samples was bioinformatically processed with a HISAT2/StringTie pipeline, utilizing reference guided assembly with the ARS-UCD1.2 bovine genome. Differentially expressed genes were identified through analyzing the impact of time across all calves, influence of vaccination across treatment groups at each timepoint, and the interaction of time and vaccination. Calves, regardless of vaccine administration, demonstrated an increase in gene expression over time related to specialized proresolving mediator production, lipid metabolism, and stimulation of immunoregulatory T-cells. Vaccination was associated with gene expression related to natural killer cell activity and helper T-cell differentiation, enriching for an upregulation in Th17-related gene expression, and downregulated genes involved in complement system activity and coagulation mechanisms. Type-1 interferon production was unaffected by the influence of vaccination nor time. To our knowledge, this is the first study to evaluate mechanisms of vaccination and development in healthy calves through RNA sequencing analysis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Scott, Woolums, Karisch, Harvey and Capik.)

The objectives of this study were to evaluate the influences of sex, breed, and backgrounding diet on rumination and activity patterns in Angus and Angus-cross beef calves; and the daily variations in rumination and activity in Angus and Angus-cross beef calves under different backgrounding systems. A total of 62 freshly weaned calves were vaccinated and randomly stratified by sex (heifers and steers), breed (Angus and Angus × Simmental cross), and assigned randomly to 3 backgrounding treatments for 55 days. The peak values for rumination and activity in heifers, steers, Angus, and Angus × Simmental cross occurred during the dark and light phases of the dark/light cycle, respectively. Beef calves backgrounded on cover crops had higher (p < 0.05) rumination (45.33 ± 1.57 min) compared with calves backgrounded on a perennial pasture (43.96 ± 1.47 min) diet. Similarly, drylot calves (24.16 ± 0.68 min) had higher (p < 0.05) activity compared to perennial pasture (23.49 ± 0.72 min). The results showed that sex and breed did not influence rumination and activity of Angus and Angus-cross beef calves during the study period. We concluded that the time of the day and backgrounding diet influenced rumination and activity patterns of Angus and Angus-cross beef calves.

Most in vivo studies related to ruminal development in calves use invasive techniques involving rumen-fistulated or euthanized animals. In consideration of animal welfare, we developed an oral endoscopic biopsy procedure to allow the obtaining of rumen epithelial samples, thus serving as an alternative for measuring the height and width of rumen papillae in calves in a safe, quick, and efficient manner that allows the slaughtering of calves to be avoided. This procedure was tested on 12 Brangus crossbred calves randomly distributed in two groups, with one fed a meal starter and the other an extruded starter feed. Calves underwent a 12-h fasting period, were restrained in a squeeze chute, administered a dose of atropine, and sedated with xylazine before the oral endoscopic biopsy procedure. A 120 cm long Olympus ® oral flexible video endoscope and forceps were used to collect cranial-dorsal sac rumen epithelial tissue samples of approximately 0.5 mm. Endoscopy was successful in all 12 calves and the collected tissue samples were placed in formalin (10%) for further processing for obtaining rumen papillae measurements. Consumption of the extruded starter feed resulted in the increased ( p = 0.035) width of rumen papillae. The oral endoscopic biopsy procedure implemented in this study was demonstrated to be successful and is thus an alternative technique for studying rumen epithelial development and morphometric alterations in calf rumen tissue.

Health and performance of early-weaned steers were evaluated during a 56-d weaning period, a 56-d feedlot receiving period, and a 165-d feedlot finishing period. Steers ( n = 239; 128 ± 14 d of age) were assigned to a 56-d weaning treatment: drylot weaning (D) or pasture weaning (P). Pasture steers grazed mature, native tallgrass range (89.2% dry matter [DM], 9.08% crude protein [CP]), without supplementation. A concentrate-based diet (18.7% CP and 1.15 Mcal NE g /kg) was fed to D steers. Later, all steers were transitioned to a receiving, then a finishing diet and fed to a common endpoint. Body weight (BW) after and average daily gain (ADG) during weaning were greater ( P < 0.01) for D than for P. Incidence of undifferentiated fever during weaning tended to be greater ( P = 0.10) for D steers than for P steers. Conversely, incidence of keratoconjunctivitis was greater ( P < 0.01) for P than for D during weaning (40.2% vs. 0%, respectively) and receiving ( P < 0.01; 14.3% vs. 1.6%, respectively). At the start and end of receiving, D steers had greater ( P < 0.01) BW compared with P steers. Drylot steers had greater ( P = 0.03) ADG compared with P steers during receiving. Pasture steers tended to have greater dry matter intake (DMI) ( P = 0.09) during receiving than D steers. In contrast, gain:feed (G:F) was improved ( P < 0.01) for P steers than for D steers during receiving. Incidence of undifferentiated fever was not different ( P = 0.99) between D and P steers during receiving. At start of finishing, D steers were heavier ( P < 0.01) than P steers; however, finishing ADG was greater ( P < 0.01) for P compared with D. Conversely, hot carcass weight of P steers was less ( P < 0.01) compared with D steers. Drylot steers had greater DMI ( P < 0.01) than P steers during finishing, whereas P steers had improved G:F ( P < 0.01) compared with D steers. There were no differences ( P ≥ 0.19) between treatments in DOF, carcass characteristics or United States Department of Agriculture yield grade. Growth and health during a 56-d weaning period and a 56-d receiving period were improved when steers were weaned in a drylot environment and fed a concentrate-based diet compared with non-supplemented steers weaned in a pasture environment. We interpret these data to suggest that, under the conditions of our experiment, steers preconditioned on mature, native, warm-season pasture for 56 d without supplementation were unable to compensate for previous nutrient restriction during finishing., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Here, we investigated the prevalence and risk factors for the presence of Histophilus somni, Mannheimia haemolytica, Mycoplasma bovis , and Pasteurella multocida in the respiratory tract of calves from the spring processing to the reprocessing at feedlots. Additionally, we characterized, phenotypically and genotypically, the antimicrobial resistance (AMR) profile of the four species. Calves from 22 cow-calf operations were enrolled in the study ( n = 30 calves per operation) and sampled by deep nasopharyngeal swabs at three time points: spring processing, weaning, or induction into feedlots, and at reprocessing at the feedlot. Isolates were tested for susceptibility using the minimum inhibitory concentration (MIC) test against commonly administered antimicrobials. Additionally, a subset of isolates underwent whole-genome sequencing to infer presence of AMR genes and resistance determinants. Among studied pathogens, P. multocida was the most prevalent species, regardless of time point, followed by M. haemolytica, M. bovis , and H. somni . For M. bovis , a sharp increase in prevalence was detected at the reprocessing sampling, whereas for P. multocida , an increase in prevalence was observed at the weaning/induction sampling. Comingling and co-location of feedlots were not associated with prevalence of any respiratory pathogen. In terms of AMR, resistance against macrolides was prevalent in M. bovis , with most isolates resistant against tildipirosin, tilmicosin, and tylosin. In general, there was limited evidence to support an increase in resistance rates of respiratory bacteria from the spring processing to reprocessing at feedlots, with the exception of florfenicol resistance in M. bovis , which increased at reprocessing. Metaphylactic administration of tetracyclines at feedlot induction was not associated with the MIC of tetracyclines in any respiratory bacteria. Conversely, there were clear associations between the parenteral use of macrolides as metaphylaxis at the feedlot induction, and increased MIC against macrolides in P. multocida, M. haemolytica , and H. somni . Overall, the AMR phenotypes were corroborated by presence of AMR genes. We hypothesize that the administration of macrolides such as tulathromycin at feedlot induction contributes to historical changes in macrolides MIC data of respiratory bacteria of beef cattle., Competing Interests: CD and EH are part owner and managing partners of Veterinary Agri-Health Services. Veterinary Agri-Health Services is a health management oriented veterinary practice based in Alberta that provides professional services to feedlot and cow/calf operations across western Canada. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Nobrega, Andres-Lasheras, Zaheer, McAllister, Homerosky, Anholt and Dorin.)

Awareness and interest in calf health and wellbeing is intensifying, prompting change in the management and breeding decisions of producers and associated policy-makers. The objectives of the present study were to 1) quantify the risk factors associated with subjectively measured scores of vigor and birth size as well as diagnoses of scour and pneumonia in a large national dataset of beef calves, and 2) to estimate the contribution of genetic variance to such phenotypic measures. After edits, the data consisted of health and birth size data subjectively scored by producers on 88,207 calves born in 6,126 Irish beef herds. Vigor was recorded on a scale of 1 (very poor) to 5 (very good). Birth size was also scored on a scale of 1 (very small) to 5 (very large). Scour and pneumonia were both scored independently based on the suspected number of occurrence of each (0 = no occurrence, 1 = one occurrence, or 2 = more than one occurrence). On average, 14.7% of calves were recorded as having had at least one occurrence of scour within the first 5 mo of life, whereas 6.4% of calves were recorded as having had at least one occurrence of pneumonia within the first 5 mo of life. Relative to female calves, male calves had a worse vigor score and a suspected greater incidence of both scour and pneumonia. Relative to singletons, twins were, on average, smaller at birth, they had a worse vigor score, and they were more prone to scour. Calves born in the later periods of the calving season (i.e., late and very late) had a greater incidence of scour relative to calves in the herd born earlier in the calving season. Heritability estimates for vigor, birth size, and pneumonia were 0.12 (0.02), 0.33 (0.03), and 0.08 (0.02), respectively; no genetic variance was detected for scour. Breeding for vigorous calves that are less susceptible to pneumonia could provide producers with an additional strategy to ensure consumer concerns regarding food quality, safety, and calf wellbeing are being met., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

This study was performed to elucidate whether the route of booster vaccination affects the immune response against respiratory vaccine viruses in pre-weaning beef calves that receive primary intranasal (IN) vaccination during the first month of life. The objective was to compare the serum neutralizing antibody (SNA) titers to BHV1, BRSV, and BPI3V, cytokine mRNA expression and mucosal BHV1- and BRSV-specific IgA in nasal secretions following administration of IN or subcutaneous (SC) modified-live virus (MLV) booster vaccines 60 days after primary IN vaccination in young beef calves. Twenty-one beef calves were administered 2 mL of an IN MLV vaccine containing BHV1, BRSV, and BPI3V (Inforce3®) between one and five weeks of age. Sixty days after primary vaccination, calves were randomly assigned to one of two groups: IN-MLV (n = 11): Calves received 2 mL of the same IN MLV vaccine used for primary vaccination and 2 mL of a SC MLV vaccine containing BVDV1 & 2 (Bovi- Shield GOLD® BVD). SC-MLV (n = 10): Calves were administered 2 mL of a MLV vaccine containing, BHV1, BRSV, BPI3V, and BVDV1 & 2 (Bovi-Shield GOLD® 5). Blood and nasal secretion samples were collected on days -61 (primary vaccination), -28, -14, 0 (booster vaccination), 14, 21, 28, 42 and 60 for determination of SNA titers, cytokine gene expression analysis and nasal virus-specific IgA concentrations. Statistical analysis was performed using a repeated measures analysis through PROC GLIMMIX of SAS®. Booster vaccination by neither IN nor SC routes induced a significant increase in SNA titers against BHV1, BRSV, and BPI3V. Subcutaneous booster vaccination induced significantly greater BRSV-specific SNA titers (on day 42) and IgA concentration in nasal secretions (on days 21 and 42) compared to calves receiving IN booster vaccination. Both IN and SC booster vaccination were able to stimulate the production of BHV1-specific IgA in nasal secretions. In summary, booster vaccination of young beef calves using either SC or IN route two months after IN MLV primary vaccination resulted in comparable SNA titers, cytokine gene expression profile and virus-specific IgA concentration in nasal secretions. Only a few differences in the systemic and mucosal immune response against BHV1 and BRSV were observed. Subcutaneous booster vaccination induced significantly greater BRSV-specific SNA and secretory IgA titers compared to IN booster vaccination., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Refractometry is used to assess transfer of passive immunity (TPI), but studies evaluating different refractometers and appropriate thresholds for recommended target immunoglobulin G (IgG) concentrations for beef calves are limited., Objectives: To evaluate test performance of digital (DSTP) and optical (OSTP) serum total protein (STP) refractometers and a digital Brix (DBRIX) refractometer for assessment of passive immunity in beef calves., Animals: A total of 398 beef calves from 6 herds, 1 to 7 days of age., Methods: Serum IgG concentration was estimated by DSTP, OSTP, and DBRIX, and measured by radial immunodiffusion (RID). Correlation coefficients (r) among results were calculated. Optimal STP and Brix thresholds for identification of IgG <10, <16, and <24 g/L were determined using interval likelihood ratios. Refractometer performance and agreement were assessed using areas under the curve (AUC), diagnostic test characteristics, Cohen's kappa (κ), and Bland-Altman analysis., Results: Refractometer results were highly correlated with RID (r = 0.82-0.91) and with each other (r = 0.91-0.95), and overall test performance was excellent (AUC = 0.93-0.99). The STP concentrations of ≤5.1, ≤5.1, and ≤5.7 g/dL and Brix percentages of ≤7.9%, ≤8.3%, and ≤8.7% indicated IgG concentrations <10, <16, and <24 g/L, respectively. Agreement of refractometers with RID was variable (κ = 0.46-0.80) and among refractometers was substantial (κ = 0.62-0.89)., Conclusions and Clinical Importance: All refractometers showed good utility as monitoring tools for assessment of TPI in beef calves., (© 2020 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC. on behalf of the American College of Veterinary Internal Medicine.)

The objectives of this study were to investigate milk casein polymorphisms in dams and to determine the impacts of maternal casein genotypes on growth traits of their sucking calves. Milk samples from 433 dams of the breeds German Angus (GA) and German Simmental (GS) were typed at the milk protein loci α s1-casein (αs1-CN), β-casein (β-CN), α s2-casein (αs2-CN), and κ-casein (κ-CN) via isoelectric focusing. Associations between casein genotypes in maternal milk with growth traits of their 1,872 calves were analyzed until the age of weaning using linear mixed models, considering either genotypes of individual casein loci (model 1) or composite α s1-β-α s2-κ-CN genotypes within the casein cluster (model 2). Besides environmental effects such as sex, age of the dam, and calving year-season, genetic effects (breed group and maternal and paternal effects) were considered in statistical models. The composite casein genotype BBǀA2A2ǀAAǀAB (order of genes on bovine chromosome 6: α s1-ǀβ-ǀα s2-ǀκ-CN) was associated with greater average daily weight gains (ADG) and heavier age-adjusted weaning weights (WW) of calves (P < 0.05). The effects of composite genotypes on birth weight of calves were similar (P > 0.05; model 2). With regard to individual casein loci, greater ADG and WW were observed for calves from dams with the genotypes κ-CN BB and α s1-CN BB, respectively (P < 0.05; model 1). Age-adjusted WW was largest for calves from dams carrying the κ-CN genotype BB (215 kg) compared with calves representing the maternal AB and AA genotypes (both 204 kg). Results from the present study suggested selectable casein genotypes due to their nutritional value of milk (value in terms of offspring performances), offering new perspectives for breeding strategies in beef cattle to improve preweaning calf performance., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The herd on-farm mortality rate is an indicator of herd animal health and welfare status. The aim of the present study was to describe herd-level on-farm mortality rates and to identify risk factors that contribute to high herd mortality rates. Online or postal questionnaires were sent to 676 Estonian beef farms, and the response rate was 25.4%. The calf (ear-tagged) and cow within-herd mortality rates for the years 2014-2016 ranged from 0.00 to 5.45 per 100 calf-months and 0.00-12.15 per 100 cow-years, respectively. The risk factors for a higher calf within-herd mortality rate in the negative binomial regression analysis were the following: calvings not being monitored at nighttime, bedding not being added daily, a low proportion of calvings occurring during summer, lack of using a consultancy service and conventional herd type compared to organic. Failure to separate sick animals and failure to use new pastures for cow-calf pairs were risk factors for cow mortality. Mortality rate was generally higher in larger herds. In order to lower the mortality rate, it is essential to ensure good calving management, a clean environment, and isolation of sick animals.

Background: The dam is considered an important source of microbes for the calf; consequently, the development of calf microbiota may vary with farming system due to differences between the contact the calf has with the dam. The objective of this study was to characterise the early changes in the composition of oral and faecal microbiota in beef and dairy calves (N = 10) using high-throughput sequencing of the 16S rRNA gene. The microbiota of calves was compared to selected anatomical niches on their dams which were likely to contribute to the vertical transfer of microbes., Results: A total of 14,125 amplicon sequence variants (ASVs) were identified and taxonomically assigned. The oral microbiota of calves and their dams were composed of more similar microbes after the first 4 weeks of life than immediately after calving. The faecal microbiota of four-week old calves was composed of microbes which were more similar to those found in the oral microbiota of calves and adult cows than the faecal microbiota of adult cows. Specific ASVs were identified in the oral microbiota of four-week old calves that were also present in cow niches at calving, whereas very few ASVs were present in the calf faecal microbiota at four-weeks of age were present in any adult cow niche at calving. These results were observed in both beef and dairy calves., Conclusions: We did not observe any marked differences in the maturation of the oral and faecal microbiota between beef or dairy calves, despite dairy calves having very limited contact with their dam. This suggests the development of gastrointestinal microbiota in calves may not be affected by continued vertical transmission of microbes from the dam. Although the calf faecal microbiota changed over the first four-weeks of life, it was composed of microbes which were phylogenetically closer to those in the oral microbiota of calves and adult cows than the faeces of adult cows. There was little evidence of persistent microbial seeding of the calf faeces from anatomical niches on the cow at calving in either beef or dairy animals.

Stocking rate is a fundamental management factor that has major impacts on animal performance, profitability, and long-term sustainability of native range ecosystems. This research was conducted to determine the effects of stocking rate on performance and economics of growing steers grazing a mixed-grass prairie on a rolling upland red shale ecological site at the Marvin Klemme Range Research Station (35° 25' N 99° 3' W). The recommended sustainable stocking rate at this location is suggested to be 25 animal unit days (AUD)/ha. Steers [ n = 836, initial body weight (BW) ± SD = 216 ± 11.7 kg] grazed at seven stocking rates ranging from 4.13 ha/steer to 1.83 ha/steer over a 7-yr period, from 1990 to 1996, with year considered the random replication. During the experimental period, overall climatic conditions were favorable for forage production with average growing season precipitation of 118% of the long-term average over the 7-yr experiment, and only 1 yr (1994 with only 57% of the long-term average) with growing season precipitation substantially less than the long-term average. Over the entire summer grazing season, average daily gain (ADG) decreased linearly ( P < 0.01) with increasing stocking rate, such that for each additional hectare available per steer ADG increased by 0.05 kg/d ( R 2 = 0.88). Contrary to ADG, BW gain per hectare over the grazing season increased linearly ( P < 0.01) with increasing stocking rate, as stocking rate increased from 4.13 ha/steer to 1.83 ha/steer BW gain per hectare doubled from 33.1 kg/ha to 66.8 kg/ha, respectively. With land costs included in the economic analysis, net return per hectare increased linearly ( P < 0.01) from $13 [U.S. Dollars [USD]) at the 4.13 ha/steer to $52/ha at the 1.83 ha/steer. For each additional hectare per steer, net return was reduced by $15.80 (USD)/steer and $15.70 (USD)/ha. In favorable climatic conditions, such as during this 7-yr experiment, economically optimal stocking rates can be more than doubled compared with the stocking rate recommended by the United States Department of Agriculture (USDA) Soil Conservation Service. Increasing stocking rates decrease individual animal performance but maximize BW gain per hectare, which leads to the increasing economic returns observed. Research is needed to determine the long-term implications of these stocking rates during unfavorable growing conditions and setting stocking rates based on seasonal weather patterns and extended weather outlook predictions., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Strategies to improve the onset of protective immunity induced by vaccination against respiratory pathogens may have a significant impact on health of newly received beef calves. The objective was to determine if the use of injectable trace minerals (ITM; Se, Zn, Cu, and Mn) concurrent with a modified-live virus (MLV) vaccine enhances the immune response and onset of protection in beef calves challenged with BVDV2 five days after vaccination. Forty-five calves were randomly assigned to one of three groups (15/group): VAC + ITM, received MLV-vaccine and ITM (Multimin®90) subcutaneously (SC); VAC + SAL, received the same vaccine and saline SC; or UNVAC, unvaccinated. Five days after vaccination (d.0), calves were challenged with BVDV2 strain 890. Health status was evaluated and blood samples were collected for leukocyte counts, BVDV1 and 2 serum neutralizing antibodies (SNA), BVDV-PCR, and percentage of CD4 + , CD8 + , WC1 + and CD25 + T-cells. VAC + ITM had lower health scores than UNVAC (d.8 and 9). VAC + ITM had higher BVDV1 & 2 SNA titers than VAC + SAL and UNVAC on d.21 and 28. Lymphocyte counts decreased in UNVAC but not in VAC + ITM or VAC + SAL (d.3 to 11). CD4 + T-cells significantly decreased in UNVAC and VAC + SAL (d.3). VAC + ITM had higher percentage of CD4 + T-cells than UNVAC (d.3 and 7). VAC + ITM had lower percentage of activated CD4 + and CD8 + T-cells than UNVAC (d.7). In summary, vaccination induced a rapid protection against BVDV2 infection. Administration of ITM was associated with increased SNA response to BVDV1 & 2, enhanced health status, mitigation of CD4 + T-cells decrease, and reduction of T-cell activation in calves challenged with BVDV2 five days after immunization. These results support the strategic use of ITM concurrent with vaccination, especially when a rapid protection is needed in newly received beef calves., Competing Interests: Declaration of Competing Interest The authors of this article, declare that there are no conflicts of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The study objective was to determine if a combined weaning and transportation stress model affected performance, antibody, endocrine, or hematological responses to modified-live virus (MLV) or killed virus (KV) respiratory vaccination in beef steers. In total, 48 calves (Day 0 BW = 226 ± 6.2 kg) from a single origin were used in a 2 × 2 factorial to evaluate main effects of stress model, vaccine type, and their interaction, resulting in four treatments ( n = 12/treatment) including non-stress control (C) with KV (CKV), C with MLV (CMLV), stress model implementation (S) with KV (SKV), and S with MLV (SMLV). The C calves were weaned at the origin ranch on Day -37 and transported 472 km to the study site on Day -21 to allow acclimation. The S calves were weaned on Day -3, transported 460 km to a research facility on Day -2, held overnight, and transported 164 km to the study site on Day -1 to mimic the beef cattle marketing process. Vaccines were administered on Day 0 and KV was revaccinated on Day 14. The animal was the experimental unit and dependent variables were analyzed using PROC MIXED with repeated measures (day). A stress model effect ( p = 0.01) existed for DMI from Day 0 to Day 7 with greater DMI for C (6.19 vs. 4.64 kg/day) when compared to S. The MLV groups had reduced ( p = 0.05) ADG from Day 0 to Day 56, compared to KV. There was a vaccine type × day ( p < 0.01) interaction with increased ( p ≤ 0.01) PI3V- and IBRV-specific antibody titers for KV on Day 21; conversely, MLV had increased ( p ≤ 0.01) BVDV titers on Days 14, 28, 35, 42, 49, and 56. Increased ( p ≤ 0.05) BRSV titers were observed in a stress model × day ( p < 0.01) interaction for S on Days 21, 28, 36, and 42; however, C exceeded S in BVDV-specific antibody concentration on Days 21, 28, and 49. A day effect ( p < 0.01) was observed for serum haptoglobin with the greatest ( p < 0.01) concentration on Day 3. Serum cortisol concentration was greater ( p ≤ 0.04) for C vs. S on Days -2, 0, 1, 3, and 5. Total leukocytes were decreased for C vs. S on Days 0, 1, 3, 5, 7, 14, and 21 ( p ≤ 0.02). A reduction ( p ≤ 0.04) in total leukocytes was observed for MLV on Days 5, 7, and 14 vs. KV. Neutrophils and neutrophil:lymphocyte were markedly increased ( p ≤ 0.01) for S on Day -2, whereas neutrophils were decreased ( p ≤ 0.01) on Days 1 and 21 for S. Monocytes were decreased on Days 1, 5 and 7 for MLV ( p ≤ 0.04) and Days -2 to 14 for S ( p ≤ 0.03). Eosinophils were reduced ( p = 0.007) for S vs. C on Day -2, yet a distinct rebound response ( p = 0.03) was noted for S on Day 0. The results indicate that S and MLV vaccination more profoundly induced immunomodulation in beef calves.

Manipulation of the rumen microorganisms during early life has emerged as a promising strategy for persistent improvement of nutrient utilisation and lowering of enteric methanogenesis. However, limited understanding of the dynamics of rumen microbial colonisation has prevented the identification of the optimum timeframe for such interventions. The present study used DNA amplicon sequencing of the 16S rRNA gene to assess bacterial and archaeal dynamics in the rumen digesta of beef calves raised on two farms from birth through to post-weaning. The colonisation patterns of both communities were influenced by age (P < 0.05) and farm of origin (P < 0.05). The bacterial community exhibited an age-wise progression during the first month of life which appeared to be partly related to diet, and settled by day 21, indicating that this may mark the boundary of a timeframe for intervention. The archaeal community appeared less sensitive to age/diet than bacteria in the first month of life but was more sensitive to farm environment. These data show that ruminal microbial composition during early life is driven by calf age, diet and local environment, and provide important fundamental information concerning the ontogeny of the rumen microbiota from birth., (© FEMS 2020.)

Aims: The principle aim of this study was to examine the association between infection with Theileria orientalis Ikeda type and growth rates of suckled beef calves on four beef farms. In addition, associations between calf sex, sampling time, and individual farm and T. orientalis Ikeda type infection intensity and haematocrit (HCT) were investigated., Methods: The study was a prospective longitudinal study in which 240 calves from four purposively selected beef farms in the North Island of New Zealand were blood sampled and weighed in late spring, mid-summer and early autumn. Two farms were from high-risk (A and B) and two from low-risk (C and D) tick areas. Blood samples were analysed to determine HCT, and the number of T. orientalis Ikeda type organisms/µL of blood (infection intensity) using a quantitative PCR assay. A calf was defined as infected if >415 organisms/µL were detected in a blood sample. Linear mixed models were used to examine associations between infection intensity, mean daily liveweight gain (MDG), HCT, calf sex and time of sampling on the four farms., Results: On Farms A and B nearly all calves were infected at each sampling time, on Farm C <30% were infected at any sampling and on Farm D infection prevalence increased from 32 to 79% between late spring and early autumn. On Farms C and D, from mid-summer to early autumn, mean MDG was 0.127 (95% CI=0.072-0.183) kg/day less for infected than uninfected calves (p<0.001). On all farms MDG was negatively associated with infection intensity for mid-summer and early autumn sampling times (p=0.037). The relationship between time of sampling and infection intensity varied between farms (p<0.001), and between male and female calves (p=0.018). Females had a higher infection intensity than males at the mid-summer and early autumn samplings. The association between HCT and infection intensity varied with sampling time and farm (p=0.018). There was a strong negative association between infection intensity and HCT at the late spring sampling, but in mid-summer there was no association, and in early autumn only a weak association., Conclusions and Clinical Relevance: This study has shown that beef farmers in the North Island of New Zealand should be concerned about the welfare effects and economic impacts of T. orientalis Ikeda type infection in suckled beef calves.

Marketing is a stressful process for beef calves, because they are removed from their environment, often weaned just before loading, loaded, transported, and unloaded. It also involves extended periods without food and water and mixing with unfamiliar animals in an unknown environment. Some studies have shown that calves sold through markets are exposed to extended fasting periods even when they undergo only short transportation times. The aim of this controlled study was to determine the consequences for beef calves of a short transportation time followed by a prolonged time without food and water on their tympanic temperature (TT), maximum eye temperature (MET), blood variables related to stress, and live weight. Ten calves were transported for 3 h and then kept in an outdoor pen for 21 h, completing a 24 h fasting period. Sampling took place before loading, after transport and unloading, and then after completing 24 h without food and water. TT, MET, blood glucose, and creatine kinase (CK) increased significantly after transportation. Live weight decreased across sample times (mean of 10 kg per calf after 24 h of fasting), which was consistent with the higher concentration of β-HB found after fasting. Further studies to measure the actual consequences of true, commercial marketing on calf welfare and productivity are needed., Competing Interests: The authors declare no conflicts of interest.

Objective: The objective of this study was to determine the effect of weaning age on intake, performance, nutrition metabolism and serum parameters of beef calves., Methods: Sixty Droughtmaster crossbred calves were assigned to 5 groups with 12 calves in each group. The calves in control group remained with the dams till the 22-week age, while the calves weaned at 28 d (4 wk), 42 d (6 wk), 56 d (8 wk), and 70 d (10 wk) of age were sent to group 4 wk, group 6 wk, group 8 wk, and group 10 wk, respectively, and then were fed on milk replacer till the 22-week age. Feed intake and body weight and size were record and blood metabolites were measured. And 24 calves of them (6 in each group) were picked randomly for digestion and metabolism trail. Feed, feces and urine sample were taken and measured., Results: Dry matter intake of calves in group 4 wk was significantly lower than those in the remaining groups from wk 17 to 22 (p<0.05). Feed efficiency of the calves was higher in groups 4 wk and 6 wk than those in groups 8 wk and 10 wk from 11 to 13 wk (p<0.05), and calves had higher feed efficiency in group 4 wk, group 6 wk, and group 8 wk than those in group 10 wk from wk 14 to wk 22. Calves in group 4 wk and 6 wk had lower body weight than group 8 wk and group 10 wk and control group at 10-week age (p<0.05) and 13-week age (p<0.05), and calves in group 6 wk had no significant difference in body weight with control group, group 8 wk and 10 wk (p>0.05) but was higher than that of group 4 wk (p<0.05). Calves in group 6 wk had higher final body weight and total gain than group 4 wk, but no difference of total gain with that of groups 8 wk, 10 wk, and control group. And weaning calves at 6-week age brought higher feed efficiency and average daily gain from wk 14 to wk 22, and higher dry matter and organic matter digestibility at 21 wk., Conclusion: It is concluded that the weaning of calves at 6 weeks of age gave positive results.

Background: Compared with weaned calves, nursed calves benefit from access to milk as nutrient-dense feed and mentoring by their dams. Both may be decisive for growth under difficult conditions such as grazing on alpine pastures, where experience could play an essential role. These factors were investigated separately by comparing nursed calves with calves weaned at 3 months of age and grazing with or without a mentor cow (n = 8 calves)., Results: Weaned calves with mentor cows spent less time lying and walked more than nursed calves. Irrespective of whether they had a mentor cow or not, the weaned calves grew slower than the nursed calves (357, 428 and 1324 g day -1 respectively). This also adversely affected slaughter weight, dressing percentage, conformation and fat cover at slaughter. In general, mentoring had no effect. Meat quality did not differ whether weaned calves were mentored or not. Nursed calves were superior in intramuscular fat content, tenderness and water-holding capacity., Conclusion: The availability of milk appeared to be much more important to the calves under demanding grazing conditions than did mentoring. The differences in growth rate were accompanied by unexpectedly large differences in meat quality, showing that early weaning was not suitable for this system.© 2016 Society of Chemical Industry., (© 2016 Society of Chemical Industry.)

The aim of this study was to evaluate the effects of beef calves' supplementation in creep feeding systems on milk yield, body weight (BW), and body condition score (BCS) of their dams on tropical pastures using a meta-analytical approach. The database was obtained from 11 experiments conducted between 2009 and 2014 in Brazil, totaling 485 observations (cows). The database consisted of 273 Nellore and 212 crossbred (7/8 Nellore × 1/8 Holstein) cows. All experiments were carried out in the suckling phase (from 3 to 8 months of age of calves) during the transition phase between rainy and dry seasons from February to June of different years. The data were analyzed by a meta-analytical approach using mixed models and taking into account random variation among experiments. Calves' supplementation (P ≥ 0.59) and the calves' sex (P ≥ 0.48) did not affect milk yield of cows. The average fat-corrected milk (FCM) yield was 6.71 and 6.83 kg/day for cows that had their calves supplemented and not supplemented, respectively. Differences were observed (P < 0.0001) for milk yield due to the genetic group where crossbred cows presented greater FCM yield (7.37 kg/day) compared with Nellore cows (6.17 kg/day). There was no effect of the calves' supplementation on BW change (P ≥ 0.11) and BCS change (P ≥ 0.23) of the cows. Therefore, it is concluded that supplementation of beef calves using creep feeding systems in tropical pastures does not affect milk yield, body weight, or body condition of their dams.

A study was carried out to investigate how common Cryptosporidium infections are in beef calves in Swedish suckler herds and to explore which species and subtypes that occur. We further aimed at identifying factors associated with shedding of Cryptosporidium oocysts in this type of calf management. The study was conducted in two regions in Sweden and included 30 herds. Faecal samples were collected from calves younger than 3 months. A brief clinical examination was done and a questionnaire was used to collect data on management routines. Faeces were cleaned and concentrated and oocysts identified by epifuorescence microscopy. Cryptosporidium positive samples were analyzed at the 18S rRNA and GP60 genes to determine species and Cryptosporidium parvum subtype, respectively. Logistic regression was used to identify factors associated with infection. Oocysts were detected in 122 (36.7%) calves from 29 (97%) herds, at 400 to 2.4 × 107 OPG. The youngest positive calves were only 1 and 2 days old. There was no association between age and Cryptosporidium infection. Cryptosporidium bovis, Cryptosporidium ryanae, C. parvum and Cryptosporidium ubiquitum were identified, with C. bovis being the major species. Two C. parvum subtypes, IIaA16G1R1 and IIdA27G1 were identified. Routines for cleaning calf pens and number of cows in calving pens were associated with infection.

The effects of weaning on beef calves of different ages were investigated. Forty male and 40 female calves were either weaned at 6 (W6, n = 40) or 8 (W8, n = 40) months of age. The vocalization activity and behaviors (feeding, lying and standing/walking) were observed during the first 3 days following weaning. Body weight was recorded at 6 and 8 months and 2 weeks following weaning. W6 animals vocalized more often than W8 calves and females more than males on day 1 (P < 0.05). The vocalization activity decreased at a higher rate in W8 than in W6 from days 1 to 3. On day 2, W6 calves spent less time lying and more standing/walking than W8 calves (P < 0.05). The behaviors did not differ between males and females. The average daily gain after weaning did not differ between weaning ages (P > 0.05), but W8 calves gained more from 6 to 8 months of age. In conclusion, weaning distress was more pronounced in W6 than in W8 calves. W8 calves also had a superior growth performance during 6 to 8 months of age. The effect of the calves' sex was less pronounced. Therefore, it is recommended to wean beef calves later than 6 months of age., (© 2014 Japanese Society of Animal Science.)

Angus×Simmental crossbred heifers (n=150) and steers (n=100) were used to evaluate 1 of 5 growing diets: 1) a corn-based growing diet (CRN); 2) a high-fat, high-protein coproduct blend; 3) a high-fat, low-protein coproduct blend; 4) a low-fat, high-protein coproduct blend; and 5) a low-fat, low-protein coproduct blend in a 2×2+1 factorial arrangement. Low-protein and low-fat diets were formulated to be isonitrogenous and isofat to CRN (16.0% CP and 3.0% fat), and high-protein and high-fat diets were formulated to have 20.0% CP and 5.0% fat, respectively. Calves were weaned at 85±1.2 d, blocked by weight, and allotted to pens (10 calves/pen) within sex (10 pens of steers and 15 pens of heifers). The objective of this experiment was to determine if the concentration of protein or fat or their interaction in coproducts used in growing diets fed to early-weaned calves affects feedlot performance or carcass composition. Starting on d 0, calves (141±1.2 d of age) were fed experimental diets for 112 d and then fed a common feedlot diet for an additional 112 d. Body weight, hip height, and ultrasound data were collected at the end of each 112-d feeding phase. Carcass data included HCW, LM area (LMA), 12th-rib back fat (BF), marbling score (MS), KPH, and USDA quality grade. There was no fat×protein interaction (P≥0.27); therefore, only main effects are discussed. No effects (P≥0.47) of CRN, protein, or fat were detected for BW at d 112 or 224. Increased dietary protein resulted in greater (P=0.04) ADG at d 112 compared to calves fed low protein. Feeding cattle CRN decreased (P=0.04) DMI and increased (P<0.01) G:F during the growing phase compared to coproducts. High-fat diets increased (P=0.05) BF in calves at d 112 compared to low-fat diets. High-protein diets decreased (P=0.02) ultrasound MS at d 112 compared to low-protein diets. Carcasses from cattle fed high-fat diets had greater (P=0.03) MS compared to those from cattle fed low-fat diets. No differences (P≥0.14) were observed for HCW, LMA, BF, KPH, or yield grade. These data indicate that final BW was unaffected by protein and fat content of growing calf diets but that increased dietary fat and low dietary protein increased MS.