Effects of Maternal Appeasing Substance and Castration Status on Growth Performance and Health in Newly Received, High-Risk Beef Calves

Abstract The objective was to determine the efficacy of a maternal bovine appeasing substance (MBAS) on growth performance, overall health, and behavioral outcomes. Crossbred calves [n = 80; steers at arrival (SAA, n = 33), recently castrated males (RCM, n = 47)] were purchased and used in a 42-d receiving study. Calves were stratified by d –1 body weight and arrival castration status (ACS), then allocated randomly to 1 of 8 groups [10 calves/group (4 to 5 SAA/group, 5 to 6 RCM/group). Groups were assigned to 1 of 2 treatments (4 groups/treatment), which included cattle receiving no maternal bovine appeasing substance (CON) or cattle that were administered a 2.5 ml dose of FerAppease (FerAppease Bovine®, FERA Diagnostics and Biologicals, College Station, TX), a MBAS which was applied topically to the nuchal skin on d 0. Calves were housed on 0.45-ha pens, provided ad libitum access to bermudagrass hay, and offered a grain supplement (1.82 kg/d) to meet or exceed nutrient requirements. Body weights were recorded on d 0, 3, 14, 21, 28, 41, and 42 and used to calculate average daily gain. Calves (5 calves/group; n = 3 RCM and 2 SAA/group) were selected for sampling on d 0, 3, 28, and 42 for serum haptoglobin concentrations. Accelerometers were placed on 16 calves (n = 1 SAA and 1 RCM/group) for 7 days to record activity. Behavior measurements inside the chute included video collections recording each calf in the chute on d 3, 14, 28, and 42, and chute exit velocity (CEV) was measured on d 3, 14, 28, 41, and 42. Data were analyzed using MIXED and GLIMIX procedures in SAS 9.4. Body weights, haptoglobin, and behavior data were analyzed as repeated measures. Kenward-Rogers was specified as the degrees of freedom selection, utilizing a diagonal covariant structure. MBAS administration did not affect overall growth performance (P ≥ 0.3902) during the 42-d period. However, there was a treatment × ACS interaction (P = 0.04) for morbidity, CON RCM had a greater incidence compared to CON SAA, and the MBAS RCM were intermediate and did not differ from the MBAS SAA. There was a tendency for treatment × ACS interaction (P = 0.08) for serum haptoglobin concentrations to be greatest for CON RCM. The interactions found between ACS and treatment suggest MBAS could improve health outcomes for recently castrated beef calves. To conclude, MBAS did not affect growth performance but could potentially be used to improve the health of high-risk calves in the following 2 weeks of receiving.