Abstract Stress can place a strain on a biological system disturbing the physiological milieu. In livestock, stressors can be deleterious to important economical functions such as reproduction. Maternal bovine appeasing substances have demonstrated the ability to reduce indicators of stress such as cortisol which can lower conception rates in beef heifers at time of first AI. This experiment was designed to evaluate the impact of utilizing maternal bovine appeasing substance (mBAS) on behavioral characteristics of beef heifers at Fixed Time AI. Hereford (n = 72) and Angus influenced heifers (n = 19) from Journagan Ranch were blocked by weight and randomly assigned to one of two treatments within each block, control (no mBAS (CON)), and those to whom mBAS was applied (mBAS). The seven-day CO-Synch + CIDR Fixed-Time AI protocol was used for estrus synchronization and artificial insemination. Heifers in the mBAS treatment received 10mL of a commercially available mBAS treatment (FerAppease), on the nuchal skin area (5mL) and muzzle (5mL) on day 1 and 9 of the study. Body weight and body condition scores (BCS) were collected at the start of the study. Changes in behavior were characterized by Chute exit (1-4; 1 = walk and 4 = jump) and chute behavior scores (1-5; 1 = calm and 5 = aggressive) collected on days 1, 10, and 14 of the study. Estrotect patches were placed on heifers on day 7 and a heat patch score (0-2;0 = inactivated, 1 = 1-50% activated, 2 = 51-100% activated) was given to each heifer at the time of AI. Chute exit scores and chute behavior scores were analyzed as repeated measures and heifer type (Hereford, Angus influenced) was included as a random effect. No statistical difference between treatments for body weight and BCS (P 0.05) were found. Chute exit scores had a significant interaction for trt x day (P 0.01). The mBAS heifers had chute exit scores of 1.4, 1.6, and 1.5 for days 1, 10 and 14 respectively and the CON had scores of 1.9, 1.7, and 1.5 for days 1, 10, and 14 respectively. Chute behavior scores were significant for the main effect of day (P 0.01) with scores of 1.8, 2.2, and 1.8 on days 1, 10, and 14 of the study respectively. There was a statistical difference in estrotect patch activation between treatments (P = 0.02). Heifers in the mBAS treatment had fewer unactivated patches and more patches at least 50% activated. While we did find behavioral differences by day, there does not appear to be a significant impact of maternal bovine appeasing substances on the behavior of heifers during FTAI but it does appear to increase the number of animals in standing heat at time of FTAI.
Branstetter et al. (Wed,) studied this question.