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 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 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 < 0.05) total post-weaning 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 < 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 weight gain throughout the post-weaning period and immune response to vaccination in recently weaned beef calves.