PS11-16. Maternal Bovine Appeasing Substance Administration at Castration Reduces Stress, Pain-related Behavior, and Respiratory Disease in Feedlot Bulls.

Abstract This experiment evaluated behavioral, physiological, and health responses of feedlot-adapted bulls administered the maternal bovine appeasing substance (mBAS; Ferappease®, FERA Diagnostics and Biologicals; College Station, TX) at the time of castration. Angus-influenced (n = 182; 239 ± 3 kg) bulls were purchased from 3 sources with no previous health and management history, and transported to the research center on d -40. Bulls were assigned to initial processing and revaccination on d -36 and -12, respectively. Bulls were ranked by body weight (BW) recorded on d -12, source, and assigned to 1 of 26 pens (n = 7 bulls/pen, 13 pens/treatment) on d 0. Pens were assigned to receive bulls administered 10-mL of mBAS or no treatment (CON) immediately prior band-castration (d 0). The mBAS was applied topically to the nuchal skin area (5 mL) and above the muzzle (5 mL), and reapplied to respective steers on d 14. Final BW was recorded on d 42, whereas feed intake and signs of bovine respiratory disease (BRD) were recorded daily. Hair samples from the tail-switch were collected on d 0 and 14. Subjective pain-related behaviors were evaluated daily from d 0 to 13 using 3-point scoring system (0 = no pain, 1 = moderate pain, 2 = severe pain). Bulls were also fitted with an ear tag (CowManager®, Agis Automatisering BV, Harmelen, The Netherlands) to record behavioral responses. No treatment effects were detected (P ≥ 0.41) for BW gain, feed intake, and gain:feed, whereas mBAS cattle tended to have greater (P = 0.08) final BW. Hair cortisol concentrations did not differ (P = 0.66) between treatments on d 0, but were less (P = 0.02) in mBAS cattle on d 14 (treatment × day; P = 0.04). Incidence of BRD signs and mean pain score were less (P ≤ 0.05) for mBAS cattle. Cattle administered mBAS spent less time (P ≤ 0.03) being not active on wks 1 to 4, spent more time (P ≤ 0.03) being highly active during wks 1 and 2, and spent more time (P = 0.03) ruminating on wk 3 (treatment × day; P ≤ 0.04). Liveweight gain from d 0 to 42 tended (P = 0.09) to be greater for mBAS pens, and final liveweight was greater (P = 0.05) in mBAS pens. Pens that received mBAS had greater (P = 0.05) final value and tended (P = 0.08) to have greater profit. Administering mBAS to feedlot-adapted bulls at the time of castration attenuated chronic stress, reduced behavioral expression of pain, decreased the incidence of BRD signs, and improved pen-based productivity during a 42-d post-procedural period.