Beef Calves Research Articles

Social interactions and movement patterns of rangeland-raised beef cows and their calves

Understanding the spatial and temporal relationships between beef calves and their dams is crucial for effective rangeland management. This study investigated these dynamics on semiarid rangeland using GPS collars fitted on cow-calf pairs. Data were collected on 46 crossbred cows and 34 calves grazing two adjacent 219 and 146 ha pastures. The primary objective was to determine the proximity of calves to their dams and other adult cows at different calf ages (1, 2 and 4 mos.). Over a 24 h period, calves spent on average 10.5 and 17.5 h within 5 or 10 m of an adult cow, respectively, and spent 2.6, 5.6 and 2.3 h within 5 m of their dams, other adult cows and a guard cow (cow other than the dam that spent the most time in the proximity of a calf), respectively. Calves spent more time within 5 or 10 m of an adult cow during night vs. daytime hours and spent detectably (P < 0.05) more time within 5 or 10 m of other adult cows vs. their dam (5.6 vs. 2.6 or 10.3 vs. 3.5 h). Calves spent a similar (P > 0.05) amount of time within 5 or 10 m of their dam vs. the guard cow (2.6 vs. 2.3 or 3.5 vs. 3.7 h) regardless of age during both day and nighttime hours. In general, calves spent more time within 5 and 10 m of an adult cow at 2 vs. 1 or 4 mos. of age. Greater mother-offspring clustering occurred at 2 vs. 1 or 4 mos. of age regardless of the spatial threshold considered. Regardless of calf age, calves and nursing cows traveled on average 4.5 and 6.7 km/day, respectively. Calves at 4 mo of age traveled farther than younger calves. Nursing cows traveled farther when calves were 4 mo. vs. 1 or 2 mos. of age and tended to travel farther when calves were 1 vs. 2 mos. old. Calves spent more time close to other nursing cows vs. their dam. These findings suggest that while dams play a crucial role in calf development, other nursing cows may also influence their foraging behaviors. Further research is needed to fully understand the dynamics of these relationships and their implications for rangeland management, such as optimizing grazing strategies and improving calf health and productivity.

Development of the calf grimace scale for pain and stress assessment in castrated Angus beef calves

Grimace scales have been used to assess pain in various animal species. This study aimed to develop the calf grimace scale (CGS), evaluate its responsiveness and the effect of external factors (change of environment and dam separation, and restraint) on CGS. Sixty-nine Angus calves, 6–8 weeks old, were randomly allocated into castrated (n = 34) and sham castrated (n = 35) groups. Images were extracted from videos pre- (M1-M4), during- (M5), and post-castration/sham castration (M6, M7). Six facial action units (FAUs) were identified: ear position, orbital tightening, tension above the eye, nostril dilation, straining of chewing muscle, and mouth opening. Final CGS median scores increased after castration (P < 0.001) for both non-restrained (M7 versus M2) and restrained (M6 versus M3) calves, indicating scale responsiveness. Final CGS median scores increased (P < 0.001) when calves were subjected to external factors before castration (M1 [baseline] versus M2 and M3). However, there was no difference (P > 0.05) in CGS median scores before and after sham castration, regardless of restraint (M3 versus M6, and M2 versus M7), indicating that the external factors may have reached a maximum effect. The CGS is composed of six FAUs, responsive to acute pain and can identify stress unrelated to pain.

Histopathologic and ultrastructural findings in oak (Quercus spp.) toxicity on 2 beef cattle farms in Colorado.

Natural oak toxicity, a phenomenon sporadically reported in the United States, is due to consumption of any part of most oak trees (Quercus spp.). Ruminants, mainly cattle, are disproportionately susceptible to oak toxicity. Toxicity is attributed to degradation of the oak plant hydrolysable tannins by rumen microbes and enzymes into absorbable low-molecular-weight metabolites, which are postulated to bind and damage endothelial cells by unknown mechanisms. The clinical manifestations of acute toxicosis are nonspecific or broadly suggestive of renal disease due to acute tubular injury. Here we document the clinical, gross, histopathologic, and novel ultrastructural features of natural acute oak nephrotoxicity in 3 beef calves on 2 farms in Colorado, USA. Gross postmortem findings included perirenal edema with renomegaly and hemorrhagic gastroenteritis. Histologically, renal tubular epithelial necrosis was severe, with hemorrhage and intratubular hyaline casts. Transmission electron microscopy revealed extensive involvement of proximal and distal convoluted tubules, with predominantly intact basement membranes, and glomerular and interstitial endothelial injury and necrosis. The ultrastructural details of toxic nephropathy and vasculopathy induced by oak metabolites in natural cases of bovine oak toxicosis have not been described previously, to our knowledge.

Dairy calves' time spent in the cow herd in a calf-driven cow-calf contact system during two-step separation with a nose flap

Although originally developed for weaning of beef calves, nose flaps are also used on dairy farms nowadays to wean calves which are reared with contact to their dam or a foster cow. These calves are often weaned younger than beef calves and the time they wear nose flaps is highly variable, since it is unknown for how long younger calves need to wear the nose flap in order to induce an effective weaning. The aim of our study was therefore to track changes in dam-contact initiated by dairy calves after insertion of a nose flap in order to determine the minimum duration a nose flap needs to be worn to effectively reduce suckling motivation of calves. The study was conducted in two sequential experiments using 3-month-old dairy calves that were reared with full-time dam contact. Calves were weaned with a nose flap over either 14 (experiment I, 9 calves in herd A and 9 calves in herd B) or 7 days (experiment II, 11 calves in herd A and 12 calves in herd B) before they were fence-line separated from their dams. The total time a calf spent within the cow herd (TIC) per day was determined from continuous video recordings during 7 days before nose flap insertion (baseline), as well as during the 7 or 14 days in which calves had free access to the cow area while wearing the nose flap. Statistical analysis was conducted using linear mixed effects models. Results from both experiments showed that calves reduced their TIC at the fourth day of wearing the nose flap compared to their individual baseline (p=0.03 and p=0.001 respectively). In experiment I, calves showed a further numerical reduction in TIC from day 4 to day 5, while in experiment II, calves showed no further reduction in TIC after the 4 days of wearing the nose flap. After these 4 or 5 days respectively, TIC of calves in both experiments stayed at a constant low level of several hours per day. Taken together, these results indicate that in 3-month-old dairy calves it needs at least 4 days until the motivation to spend time with the cow decreases after insertion of a nose flap, while there seems to be no further decrease in motivation when using a nose flap longer than this time. However, results were subject to considerable inter-individual variability already during the baseline week and need replication in a pasture-based setting with less space-restrictions.

WITHDRAWN: First report of Toxocara vitulorum infection in a dairy calf in Tennessee

The ascarid nematode, Toxocara vitulorum is a destructive parasite of ruminants with a world-wide distribution that causes mortality in calves, especially those with poor nutrition. Reports of Toxocara vitulorum are scarce in the continental United States and Canada. A single gravid female T. vitulorum was discovered on the necropsy of a 2.5-month-old mini jersey calf from a dairy farm in Sparta, TN. Genetic analysis of the 18S and COI genes revealed a 100 % match to T. vitulorum samples isolated from beef calves in Iowa and a 96.73 % match to T. vitulorum isolated from a yak in Austria, respectively. Although perforation of the small intestine was seen in the calf and is the typical cause of death in calves with high burdens of this worm, it is unknown if this single nematode infection contributed to the cause of death in this case. The source of the infection in this calf also remains unknown. Fecal centrifugal flotations on the rest of the herd (n = 8) did not produce any T. vitulorum eggs, even in the 2 calves that were under 6 months old on the farm. We were unable to obtain milk to test for T. vitulorum larvae from the calf's mother. This is the first report of T. vitulorum in dairy calves in the US and the first report of this parasite in Tennessee. Given the devastation caused by this parasite in cattle and bison herds in other countries, further studies to determine the prevalence and pathogenicity of this parasite in the US are vital to prevent spread of this parasite to other vulnerable species and to prevent economic losses in the animal industry.

PSVIII-9 Effects of growth implants and timing of vaccination on calf immunity and growth performance

Abstract This study assessed calf growth performance and blood parameters of beef calves under different growth implants and timing of vaccination protocols. Crossbreed beef calves (n = 59) were stratified by birth body weight (BW) and age (41 ± 5.2 kg of BW and 70 ± 8 d of age) and randomly assigned in a split-plot design with implant strategy as the main plot and timing of vaccination as the subplot. The main plot (treatment) consisted of 3 implant strategies: 1) Synovex C (SC; n = 20; 100 mg progesterone/10 mg estradiol benzoate, or 2) Synovex One Grower (SG; n = 19; 150 mg trenbolone acetate and 21 mg estradiol benzoate; or 3) no implant (CON; n = 20). Subplot treatments were the timing of vaccination booster against bovine respiratory disease pathogens on 1) weaning (WV; n = 29) or 2) 7-d post-weaning (PWV; n = 30). Cow-calf pairs were treated alike in a single pasture during the pre-weaning phase, receiving the same vaccine (Bovi-Shield Gold One Shot and Ultrabac 7) on d 0 (implantation day) and booster time (WV or PWV). After weaning (approximately 187 d of age), calves were allocated in a single pen receiving ad libitum hay until d 60 post-weaning. Body weight and blood were collected on d 0, weaning, d 0 and 28 relative to vaccination booster, and d 60 post-weaning. Blood was collected to determine insulin-like growth factor (IGF-1), cortisol, and leptin concentrations and to perform a complete blood cell count. WV calves had decreased cortisol concentrations on booster day and 28 d post-vaccine (P = 0.01). Regardless of implant treatment, calves tended to have decreased IGF-1 concentrations 28-d post-vaccine booster (P = 0.09). An effect of treatment (P &amp;lt; 0.01) was detected for lymphocyte counts, with CON having greater concentrations vs. SG and SC calves. A treatment × timing of vaccination (P &amp;lt; 0.01) interaction was detected for monocyte counts, where SG-PWV calves had the greatest concentrations. A treatment effect (P &amp;lt; 0.02) was observed for eosinophil percentage, where SG had reduced percentages than CON, while SC was intermediate. An effect of treatment was detected for leptin (P &amp;lt; 0.01), with SG calves having the least, CON being intermediate, and SC the greatest concentrations. From d 0 to 60 d post-weaning, SG tended to have greater ADG (P ≤ 0.07) compared with CON, while SC was intermediate. On d 28 and d 35 post-weaning, calves implanted with SG were heavier (P ≤ 0.04) than the CON but not than SC. In summary, this study demonstrates that growth implants and timing of vaccination significantly affect both physiological parameters and growth performance in beef calves. Implanting calves with Synovex One Grower resulted in improved growth performance.

PSXI-1 Evaluation of weaning methods on performance and immune response to vaccination in beef calves

Abstract The weaning process is a stressful experience for any species. Various weaning methods have been used in beef cattle to mitigate this stress and its associated consequences, such as decreased growth rate and suppression of the immune system. The objective of this study was to evaluate different weaning methods and their effect on post-weaning growth and immune function in beef calves. To accomplish this, a sample of Angus and Angus cross beef calves (n = 147) were stratified by age, sex, and sire and divided into three treatment groups: abrupt weaning (AW), fence line weaning (FL), and nose flap weaning (NF). All calves were vaccinated at weaning (d 0) and weaned according to their treatment group. Blood samples (5 mL) were collected via coccygeal venipuncture on d 0 and 14 to evaluate immune response to vaccination and quantify cortisol concentration as an indicator of stress. Individual body weights (BW) were recorded biweekly for 42 d after weaning. Data were analyzed using the PROC MIXED procedure of SAS v9.4 with main effects of treatment and sex and their interaction using ANOVA. Weaning weight, post-weaning weights, and post-weaning BW gain data were analyzed with age of calf included as a covariate. Body weights were not different among treatment groups at weaning, or at 14, 28, or 42 d post-weaning; however, the FL group had a greater (P &amp;lt; 0.05) total post-weaning BW gain than the AW group with the NF group being intermediate to the others. There was no effect of weaning method on cortisol concentration at weaning or 14 d post-weaning, but a difference in immune response was observed. Calves in the NF weaning group had a greater (P &amp;lt; 0.05) immune response to vaccination as determined by antibody titers than calves in the AW or FL weaning groups. Based on the results of this study, alternative methods of weaning may have a positive impact on calf BW gain throughout the post-weaning period and immune response to vaccination in recently weaned beef calves.

PSI-1 Genetic and non-genetic factors influencing beef cattle attractiveness to horn fly

Abstract Horn flies are the most common summer pests of cattle, leading to substantial economic losses due to impaired production and decreased animal welfare. Genetic and non-genetic factors have been reported to influence cattle susceptibility to horn flies. However, the wide range of heritability estimates, and few identified genomic regions associated with cattle resistance to horn fly may be due to subjective assessment in collecting the fly load phenotype and the small size of the population assessed. Here, beef calves from the UF purebred Brahman (BRA) and Multibreed Angus-Brahman (MAB) populations were video recorded at weaning using a GoPro camera mounted on the top of the chute. Fly infestation was determined as the average fly count obtained from five longitudinal images of each animal using ImageJ software. A total of 748 crossbred and 415 purebred calves born from 2021 to 2023 were evaluated during summer (August or September). Analysis of variance (ANOVA) was performed within herd by fitting linear models that included collection date, age, skin color, coat color, and pre-weaning average daily gain (ADG) as fixed effects, and residual as a random effect. For MAB calves, breed groups (BG) determined based on the percentage of Brahman breed, with BG1 ranging from 0 to 19%, BG2 from 20 to 39%, BG3 from 40 to 59%, BG4 from 60 to 79%, BG5 from 80 to 100%, were also fit in the model. Fly count was transformed to a natural log value (log[count +1]) ensuring normally distribute residuals. As expected, darker colors were significantly more attractive to horn flies, while animals with greaterr percentage of Brahman were less susceptible than animals with greater percentage of Angus breed. Considerable variability in fly load was observed within purebred Brahmans, indicating that additional genetic factors, other than breed, influence cattle resistance to flies. Positive estimates were observed between horn fly load and average daily gain in both herds, which can be due to the fly load below the previously reported economic injury level of 200 flies (BRA: 28.78 ± 38.20, MAB: 19.31 ± 26.72). Variance components were estimated within herds by fitting the same aforementioned effects and a genomic-based relationship matrix (G) constructed with genotypes from the GeneSeek Genomic Profiler F250 SNP chip. The moderate heritability estimate demonstrates the feasibility of selecting cattle resistant to horn flies. Overall, our findings have the potential to contribute to reducing losses and costs in beef cattle operations, while reducing the impact on the environment of overuse of insecticides.

PSV-16 Evaluation of upper respiratory and fecal microbiomes in neonatal beef calves

Abstract There is a critical lack of information on the timing of colonization of bovine respiratory disease-related bacteria in the upper respiratory tract, potentially affecting calf health and disease onset. The objective of this study was to evaluate the upper respiratory tract and fecal microbiomes of neonatal beef calves during the first 24 h of life compared with their dams at the time of birth. Late-gestation commercial beef cows (n = 28) were assigned to individual, soil-surfaced pens (6.25 x 2.29 m) fitted with canvas tarps on shared fences to limit contact between unrelated pairs. Left nasal (LN), right nasal (RN), fecal, and vaginal swab samples were collected from cows at a single time point promptly after parturition. Swabs of the LN, RN, and rectum were collected from calves at birth (0 h), 6, 12, and 24 h post-parturition. Samples were flash-frozen and stored at -80°C until processing. DNA was extracted from swabs using Power Soil Pro kit. Extracted DNA was used to prepare DNA libraries for full-length 16S rRNA gene sequencing on a MinION Mk1C device. Sequenced reads were classified using Centrifuge and used in microbiome analyses conducted in R to estimate the changes in the microbiome according to animal type (cow versus calf), time of collection, and sample type (nasal, fecal, or vaginal). Upper respiratory microbiomes significantly differed (P &amp;lt; 0.005) between cows and their offspring at birth. In nasal microbiomes, animal type explained 12.6% (P = 0.002) and 18.5% (P = 0.001) of variance in beta diversity in left and right cavities, respectively. Animal type explained 42.1% of the beta diversity variance in fecal microbiomes (P = 0.001). Nasal microbiomes at birth were significantly more dispersed in dams compared with their calves in both the LN (P = 0.03) and RN (P = 0.03). Similarly, fecal microbiomes of dams were significantly more dispersed (P &amp;lt; 0.0001) than those of their offspring. There was a clear transition of the microbial communities associated with calf age in the upper respiratory and fecal niches. Calf age accounted for 2% (P = 0.02), 3.5% (P = 0.001), and 28% (P = 0.001) of the variance in the beta diversity of the LN, RN, and fecal microbiomes, respectively. After adjusting for calf age, the laterality of nasal microbiomes was not significantly (P = 0.682) associated with the composition of microbial communities. In conclusion, calf microbial communities were dissimilar to that of their dam at birth. Additionally, microbial community transition was evident with each subsequent sampling time point, potentially influenced by the presence of the dam.

PSIX-21 Can seeds rich in polyunsaturated fatty acids reduce methane emissions when substituting palm oil on dairy beef calves fed high-concentrate diets? In vitro screening

Abstract The aim of this study was to evaluate the rumen in vitro methane (CH4) production of concentrates feed with a different protein source (PS) replacing partially palm oil by different seeds (SE) rich in polyunsaturated fatty acids (PUFA). Concentrate PS were: T1 = 8% soybean meal; and T2 = 15% dried distillers grain. Palm oil (CTR; 4% and 3.5% for T1 and T2, respectively) was partially substituted (1%) by flax seed (FL; 2.7%), canola seed (CO; 3%) or sunflower seed (SU; 2.3%), thus 8 concentrates were tested. Samples were ground at 1-mm and used in an in vitro digestibility assay. The rumen liquid was obtained at the slaughterhouse. Two incubation sets were done; two sampling points lasted 24 and 48 h to calculate the dry matter (DM) digestibility; a third sampling point lasted 12 d to monitor the CH4 production. Data were analyzed using a mixed effects model. Net volume of CH4 per degraded DM presented a PS effect (P &amp;lt; 0.01); T1 produced greater net volume of CH4 per degraded DM than T2 (8.12 vs. 6.91 ± 0.330 ml/mg, respectively). Furthermore, net volume of CH4 per degraded DM presented a SE effect (P &amp;lt; 0.01); all concentrates with seeds tested reduced the net volume of CH4 per degraded DM compared with CTR, and specifically CO produced lower net volume of CH4 per degraded DM than FL and SU (8.91, 7.47, 6.28, 7.39 ± 0.467 ml/mg; CTR, FL, CO, SU, respectively). In conclusion, the use of flax, canola, or sunflower seeds to partially substitute palm oil in concentrate feed, regardless of its PS, can be potential strategies to reduce rumen CH4 emissions, and seems that canola seed may be the most effective one.

PSXI-22 Effects of a palatability enhancer and olive bioactives on performance and physiological status of veal calves after farm reception

Abstract Veal calves have to deal with several stressors early in life, such as transport and commingling with animals of unknown health histories from multiple different origins; making the reception a possible critical period where animals should adapt to all these challenges. Previous studies in unweaned rosée calves have shown that the use of feed additives (FA) to enhance intake and immunity at farm arrival could be a strategy to minimize the negative effects of stress and feed restriction during transportation. The aim of this study was to evaluate the effects of a palatability enhancer (PE) and olive bioactives (OB) on performance and serum biomarkers in veal calves. Dairy beef calves [n = 252; BVD-free; body weight (BW) = 44.6 ± 3.63 kg] coming from auction market were distributed in 3 treatments (84 animals/tr) during 8 wk: i) calves fed concentrate and MR without FA (negative control, NC); ii) calves fed concentrate and MR with a PE based on sweeteners (PE); and iii) calves fed concentrate with PE and MR with PE and OB (PEOB). On farm arrival animals were housed individually until 5 wk of age, when animals were grouped in pens of 4 calves. Performance was monitored during the trial and serum samples were collected 48 h after the mixing (25 animals/tr) to analyze several biomarkers related to immune system (MILLIPLEX MAP Kit) and energy status (BHBA). Performance data were analyzed with a mixed-effects model and serum biomarkers by One-Way Anova with Fisher’s LSD correction for multiple comparisons (normally distributed data) or by non-parametric Kruskal-Wallis test with Dunn’s correction (data not normally distributed). Final BW was greater (P = 0.01) in PE and PEOB groups compared with NC (+2.2 kg and +2.6 kg, respectively). Concentrate feed intake (FI) during first 4 wk tended (P = 0.06) to be greater in PEOB compared with NC (+15%); however, after grouping (wk 5 to wk 8), PE showed a ldecreased FI compared with NC (-9.5%, P = 0.01). Forty-eight hours after animal grouping, PEOB showed reduced concentration of tumor necrosis factor (TNF) α than NC and PE (P = 0.03). Moreover, PEOB and PE had a greater concentration of interleukin (IL) 36Rα (P &amp;lt; 0.05) and IP10 (P &amp;lt; 0.01) compared with NC. Besides PEOB tended (P &amp;lt; 0.15) to have decreased concentrations of MIP1α, IL1α, and BHBA compared with PE. In conclusion, the addition of a PE and OB improved the adaptation of veal calves after reception, resulting in greater final BW. The improvement in early FI and the immunomodulatory effect in challenging situations displayed by the treatments may partially explain the observed benefits.

PSIV-4 Effectiveness of maternal bovine appeasing substance on growth, physiological, and behavioral responses of high-risk stocker cattle

Abstract Stocker cattle purchased at auction can be susceptible to disease due to the stressors associated with the auction process. These cattle are labeled “high-risk” due to their decreased immune system during transportation, handling, and vaccination processes. The objective of this study was to determine the efficacy of a maternal bovine appeasing substance, FerAppease, on growth performance and fearfulness of stocker cattle. Male beef calves (n = 80) were purchased at auction and transported to the University of Arkansas Division of Agriculture Savoy Research Complex Beef Stocker Unit. Steers and bulls were of varying age, breed, and temperament. Upon arrival to the facility (d 0), bulls (n = 48) were castrated by banding and cattle were assigned to 8 pens (n = 10 calves/pen; 4 bulls and 6 steers/pen). On d 0, cattle in 4 pens were treated with FerAppease (FA) on the nuchal skin (n = 40) and cattle in the other 4 pens were not treated and served as controls (CON, n = 40). All cattle received commercial clostridial and respiratory vaccines and were treated with an anthelmintic. Cattle were offered bermudagrass hay for ad libitum intake and were fed a grain supplement (1.8 kg/d) to meet or exceed nutrient requirements. To measure growth performance, body weight (BW) was recorded on d 0, 3, 14, 28, 41, 42 of the study and used to calculate average daily gain (ADG). Body weights on d 41 and 42 were averaged to calculate final BW. To measure fearfulness, exit chute velocity (ECV) was measured with a rodeo timer and recorded on d 3, 14, 28, 41, and 42. To measure inflammation, blood was collected from 5 calves/pen (n = 3 bulls and 2 steers/pen) on d 0, 3, 28 and 42 and haptoglobin (Hp) was measured in blood serum. A two-way ANOVA with the fixed effects of sex (arrived as steer or bull) and treatment (FA, CON) and random effect of pen was used for analysis. Serum Hp was log transformed to improve normality. There was not a treatment effect on any of the measures collected. Steers had a greater BW throughout the study (P ≤ 0.05), weighing more than bulls at the end of the study (261 kg vs 241 kg, respectively). Steers also had a greater (P &amp;lt; 0.0001) ADG than bulls (1.14 vs. 0.84 kg/d, respectively). On d 3 and 14, steers exited the chute more rapidly (P &amp;lt; 0.05) than bulls. There was an interactive effect on serum d 28 Hp concentrations (P = 0.04), where CON bulls had greater Hp concentrations (111,261 ng/mL) than CON steers (13,055 ng/mL), with FA steers and bulls intermediate. The results from this study indicate that there was no consistent effect of the treatment on the measures collected.

PSXIII-1 Sensory additives improved the recovery of commercially marketed and transported unweaned dairy beef calves at rearing farm arrival

Abstract Calf recovery after arrival at the rearing farm in unweaned calves is impaired by periods of stress, feed restriction and fasting during marketing and transportation. The use of feed additives to enhance intake at arrival could be a strategy to minimize those negative effects. A total of 72 calves (71.4 ± 1.72 kg) gathered in a commercial assembly center and transported 9 h to a rearing farm were used to evaluate the effect of a sensory additive (SA) on performance in calves fed 2 L of milk replacer twice daily at 12.5% and ad libitum concentrate feed. Calves were allocated in 8 pens and distributed in 2 treatments (4 pens/treatment): calves fed a concentrate without SA since the beginning of the study (arrival to the rearing farm after transport) until weaning (CON; n = 36); calves fed a concentrate containing SA (SEN; n = 36) from arrival until weaning. Calf body weight (BW) and pen intake were recorded weekly. On d 21 of the study, calves were partially weaned and only milk replacer was offered in the morning, and on d 28 all calves were completely weaned. The study lasted 35 d. Data were analyzed with a mixed-effects model. Average daily gain was greater (P = 0.04) for SEN calves compared with CON calves (0.68 ± 0.019 kg/d and 0.61 ± 0.019 kg/d, respectively). Final BW of SEN calves (95.5 ± 0.89 kg) tended (P = 0.06) to be greater compared with BW of CON calves (93.1 ± 0.89 kg). Finally, average concentrate intake was greater for SEN calves (0.89 ± 0.023 kg/d) compared with CON calves (0.79 ± 0.023 kg/d). Unweaned dairy beef calves receiving sensory additive improved concentrate intake and growth at farm arrival improving their recovery.

111 Factors affecting transfer of passive immunity in beef calves

Abstract Data from 9 calving experiments were used to investigate relationships of dam, calf, and colostrum factors with passive transfer in beef calves. Serum was collected at 48.33 ± 1.25 (SD) h of age for 313 calves, and single rear quarter colostrum yields were determined pre-suckling for dams of 117 calves. Serum and colostrum IgG concentrations were determined by ELISA. Relationship of serum IgG with colostrum variables was determined using Pearson correlation coefficients. Serum IgG was positively correlated (P ≤ 0.002) with colostrum IgG (r = 0.47) and protein (r = 0.45) concentrations and colostrum total IgG (r = 0.28) but tended to be negatively correlated (r = -0.17, P = 0.06) with colostrum yield. Based on passive transfer thresholds in the literature, 3 calves (0.96%) had &amp;lt; 8 mg/mL serum IgG, 16 calves (5.1%) &amp;lt; 16 mg/mL, and 43 calves (13.7%) had &amp;lt; 24 mg/mL. For this analysis, calves with serum IgG &amp;lt; 24 mg/mL at 48 h were considered to have failure of passive transfer (FPT). Continuous variables (dam BW and calf size, 48-h serum chemistry panel, and time to stand) were compared for FPT versus non-FPT calves using a mixed model with FPT class (fixed effect) and experiment (random effect). Calves with FPT had less (P ≤ 0.03) circulating triglycerides, glucose, calcium, magnesium, total protein, globulin, and gamma-glutamyl transferase but greater (P ≤ 0.001) circulating non-esterified fatty acids, sodium, chloride, and total bilirubin than non-FPT. Effects of categorical variables on calf 48-h serum IgG were determined using separate mixed models with variable (fixed) and experiment (random). Primiparous dams gave birth to calves that had less (P = 0.05) serum IgG at 48 h than multiparous dams. Calves born to moderate dams (BCS = 5) had less (P = 0.007) serum IgG than those born to fleshy dams (BCS ≥ 6) and tended to have less (P = 0.08) serum IgG than calves born to thin dams (BCS &amp;lt; 5). Calf sex, calving season, calving difficulty score, and vigor score at 10 min did not affect (P ≥ 0.19) serum IgG. Relationships of calf 48-h serum IgG with continuous variables was also determined using Pearson correlation coefficients, and only r ≥ 0.20 or ≤ -0.20 are reported. Serum IgG was positively correlated (P ≤ 0.005) with 48-h serum total protein (r = 0.75), globulin (r = 0.76), gamma-glutamyl transferase (r = 0.32), and potassium (r = 0.20). Serum IgG was negatively correlated (P &amp;lt; 0.001) with gestation length (r = -0.22) and 48-h serum albumin (r = -0.43), sodium (r = -0.24), and total bilirubin (r = -0.27). Overall, beef calves in this dataset generally had successful passive transfer that was associated with several dam, calf, and colostrum factors.

PSII-5 Effect of short-term feeding of hemp (Cannabis sativa) on stress biomarkers in weaned beef calves

Abstract Hemp research is growing rapidly due to its health benefits for animals; however, there is little information on its effects on stress. The objective of this study was to determine the effects of hemp supplementation on stress biomarkers in beef calves during weaning. Calves (n = 12) were completely randomized into Control (CC: received commercial concentrates before and after weaning), Treatment 1 (CH: received commercial concentrates before weaning and 25 g of hemp diet after weaning), Treatment 2 (HC: received 25 g hemp diet before weaning and commercial concentrates after weaning) and Treatment 3 (HH: received 25 g hemp diet before and after weaning). The study lasted for 28 d; blood samples were collected at 7-d intervals for enzyme-linked immunosorbent assay. Plasma was analyzed for heat shock protein 90, cortisol, haptoglobin, total antioxidant capacity, and glutathione peroxidase. There was treatment x time interaction in cortisol concentrations, with the (CH) group showing the greatest concentration of cortisol (124.23 ng/mL) in wk 3. There was no significant (P = 0.0675) difference in total antioxidant capacity. There was a treatment x time interaction (P = 0.0009) in glutathione peroxidase concentrations, with the (HH) group showing the greatest concentration of glutathione peroxidase of 46.83 ng/mL in wk 2 and 47.57ng/mL in wk 3. There was no significant (P &amp;lt; 0.05) difference in heat shock protein and haptoglobin. We concluded that hemp supplementation could reduce weaning stress in beef cattle, thereby improving the productivity and performance of beef calves

19 Strategies to optimize the trace mineral status of weaned beef calves

Abstract Trace mineral nutrition of pre-weaned beef calves is derived from 1) tissue stores at birth, 2) milk, 3) forage, and 4) supplement. In most production systems, calves are born with adequate trace mineral status, namely Cu, Zn, Mn and Se. One exception, however, is severe Se deficiency in the dam which may result in White Muscle Disease in Se-deficient calves shortly after birth. Despite general adequacy at birth, tissue concentrations of these elements often decrease during the pre-weaning period due to inadequacies in milk and trace mineral deficiency of forages. Trace mineral losses are further exacerbated by a variety of stressors naturally occurring throughout the production system, including, but not limited to, environmental, social, and immunological. Weaning, which is unavoidable in modern production systems, is the most stressful experience a beef animal will experience in their lifetime. To avoid deficiency at weaning, trace mineral deficits must be addressed through supplementation during the pre-weaning period. One of the most common supplementation methods involves the blending of supplemental trace minerals with common salt, offered free choice. This system assumes that cattle have a “nutritional wisdom” to consume salt at a level that meets their requirement for Na. Although largely effective in most grazing situations, this management system is not without complications. Notably, salt-based, free-choice mineral supplements are offered simultaneously to cow/calf pairs with known variation in voluntary intake. The necessity to understand and manage free-choice intake is the basic principle behind all successful free-choice mineral supplementation systems. In tropical and subtropical climates, where a large percentage of the world’s beef is produced, cattle are typically enrolled in year-long grazing schedules that are characterized by dry and wet seasons. In these environments, the craving for salt increases as forage DM decreases resulting in large seasonally impacted reductions in voluntary intake of salt-based, free-choice mineral supplements. During the dry season, when forage moisture is low, free-choice, salt-based mineral consumption often does not meet anticipated target levels due to a reduced natural craving for salt. There are other examples where seasonal variation in salt craving impacts the effectiveness of targeting appropriate voluntary intake of free-choice mineral supplements. For example, in some coastal regions of the world, salt-water intrusion will impact the Na content of forages and drinking water. In these regions, cattle may avoid salt-fortified supplements because of excessive Na intake from other sources. Fortunately, if we understand these regional and climatic impacts, there are effective management interventions that may be adopted to protect against trace mineral deficiency resulting from inadequate free-choice intake. This symposium presentation will review multiple pre-weaning mineral supplementation systems that have been shown to be effective for optimizing the mineral status of weaned beef calves.

363 Effects of supplementation of vitamin B complex on the performance of beef calves during a 42-d preconditioning program

Abstract The objective of this study was to evaluate the effects of supplementation of vitamin B complex on post-weaning performance of beef calves. The study was conducted during fall of 2023 at Eastern Oregon Agriculture Research Center (EOARC; Burns, OR). At weaning (d 0), 63 calves [Angus × Hereford; body weight (BW) = 252 ± 3.6 kg] were randomly assigned to 1 of 3 treatments: 1) Control, 2) VitB1, or 3) VitB2. Calves assigned to Control treatment served as a negative control and were not supplemented with vitamin B complex. Calves assigned to treatment VitB1 were supplemented at 1g/calf daily, while calves assigned to VitB2 treatment were supplemented at 2g/calf daily of vitamin B complex during the 42 d of preconditioning. Upon weaning processing, calves were allocated to 21 pens (3 calves/pen) and treatments were allocated to each pen (7 pens/treatment). Vitamin B complex [Vivalto, pantothenic acid (B5; 40,000 mg/kg), pyridoxine (B6; 20,000 mg/kg), folic acid (B9; 3,200 mg/kg), biotin (B7; 3,200,000 mcg/kg), cobalamin (B12; 320,000 mcg/kg); Selko USA, Indianapolis, IN] supplementation was offered at pen level beginning on d 1 and until the end of the preconditioning phase (d 42). Vitamin B complex was offered to calves assigned to vitamin B complex treatment mixed with 1.3 kg of dried distiller’s grains. Additionally, calves had free access to chopped alfalfa-grass hay mix and whole corn. Pen intake was recorded daily. On d 0, BW and blood samples were collected from all calves. Additional blood and BW were collected on d 1, 3, 7, 14, 21, 42 post-weaning. Body weights were used to calculate calf average daily gain (ADG) and blood samples were assayed for acute phase proteins (ceruloplasmin and haptoglobin). Additional blood samples will be analyzed for cortisol and vitamin B concentrations. Variables were analyzed considering pen as the experimental unit and pen(treatment) as a random effect. Blood variables were evaluated as repeated measures and effects of treatment, day, and treatment the interactions were analyzed with the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC). Significance was set at P ≤ 0.05. No treatment effects (P = 0.98) were observed for final BW (283, 283, and 284 kg respectively for Control, Vit1, and Vit2) or for ADG (P = 0.53; 0.735, 0.795, and 0.747 kg/d respectively for Control, Vit1, and Vit2). Similarly, no treatment effects were observed for the acute phase proteins analyzed, ceruloplasmin (P = 0.66; 27, 30, and 33 µg/dL respectively for Control, Vit1, and Vit2) and haptoglobin (P = 0.41; 0.55, 0.62, and 0.59 mg/mL, respectively for Control, Vit1, and Vit2). Supplementation of vitamin B complex to beef calves post-weaning does not seem to affect calf performance, regardless of the level of supplementation.

271 Does social buffering amongst familiar weaned beef calves mitigate castration stressors?

Abstract Co-mingling of beef feeder calves from multiple sources results in biological and behavioral stressors. This study is part of a project exploring social relationships between individual beef cattle and potential benefits of social buffering during stress events. Here, the specific objective was to explore whether feeder calves form preferential relationships which buffer them from surgical castration pain. Within the experiment, two treatment groups were established: Familiar calves were defined as calves who shared a source farm with two other calves in the pen, and Unfamiliar calves were defined as calves who did not share a source with any other pen-mates. It was hypothesized that Familiar calves would exhibit more lying, fewer pain-related behaviors, and fewer agonistic interactions following surgical castration than Unfamiliar pen-mates. Weaned beef bull calves [n = 102, body weight (BW) range ± SD = 112.95 to 370.10 ± 67.8 kg] from 23 source farms were randomly assigned to home pens, each comprised of three Familiar calves and three Unfamiliar calves. Cameras placed above the pens recorded video from which postural (standing and lying), social (agonistic and bunk displacements) and pain-related behaviors (wound checking and hind leg stamping) were quantified. Cattle were handled through a hydraulic squeeze chute once weekly over four consecutive weeks for data collection and standard processing procedures. On d 14 relative to arrival, calves were surgically castrated with multimodal pain mitigation. During all processing events, calves were marked with livestock paint for behavioral observations. Behavior was observed continuously for 15 min at five different time points (0 h, 1 h, 4 h, 24 h, 48 h) relative to when the last calf returned to the home pen after processing, and researchers were blind to treatment allocation. These time periods corresponded to expected periods when pain was absent and present based on duration of local anesthesia and systemic pain relief. Calf was the experimental unit. For the purpose of this abstract, data from the 48 h periods following d 7 and 14 were analyzed using the PROC GLIMMIX procedure of SAS; the model included treatment (Familiar, Unfamiliar) by week interaction. A P-value of ≤ 0.05 was considered significantly different. Regardless of treatment, preliminary analyses identified decreased lying (P &amp;lt; 0.02) and increased wound checking (P &amp;lt; 0.01) 48h following castration (d 14) when compared with the previous week (d 7). There were no observed differences for hindleg stamping (P = 0.2), agonistic behaviors (P &amp;gt; 0.06) or bunk displacement (P = 0.09). Based on preliminary analyses, we did not observe evidence of social buffering effects on castration stress during the immediate post-surgical period.

388 Effects of maternal nutrient restriction during late gestation on pre-pubertal beef calf testis size and histology

388 Effects of maternal nutrient restriction during late gestation on pre-pubertal beef calf testis size and histology

482 Using growth implants in suckling beef calves enhanced vaccine response against Infectious Bovine Rhinotracheitis

482 Using growth implants in suckling beef calves enhanced vaccine response against Infectious Bovine Rhinotracheitis