2 Effects of Multiple Bovine Appeasing Substance Administration During a 42-Day Preconditioning Program on Physiologic, Health, and Performance Responses of Feeder Cattle

Abstract This experiment evaluated the effects of multiple bovine appeasing substance administration during a 42-day preconditioning program followed by feedlot receiving period on productivity, health, and physiological variables of feeder cattle. Ninety recently weaned calves were obtained from Red Bluff Ranch (Norris, MT). All calves were weaned and weighed (prior to transport). Calves were loaded into a livestock trailer, transported for 70 km, and unloaded at the Bozeman Agricultural Research and Teaching Farm for a 42-day preconditioning program. Upon arrival, calf body weight was recorded, and both pre- and post-transport body weight were averaged and used as calf weaning initial body weight. Calves were sorted by body weight, sex, and age, and assigned to receive 1) multiple administration of bovine appeasing substance at weaning (d0), d 14, 28, and before transport and feedlot entry (d 42; BAS; RSEA Group, Quartier Salignan, France), or 2) placebo (diethylene glycol monoethyl ether; CON). Treatments (5 mL) were applied topically to the nuchal skin area of each animal every 14 d during the preconditioning period. Calves within treatment groups were ranked by initial BW, sex, and age, and allocated to 1 of 18 drylot pens. On day 42, calves were combined within treatment group, loaded into 2 different single double-deck commercial livestock trailers, and transported for 1000 km (approximately 16 h). Upon arrival (day 43), calves were unloaded at the same feedyard and with the same pen distribution used prior to transport and fed ad libitum a TMR diet. Blood samples were collected on day 0 (weaning), 3, 7, 14, 21, 28, 42 (prior transport), 43 (feedlot arrival), 46, 50, 57, 64 and 90. Average daily gain and final BW did not differ (P > 0.52) between BAS and CON calves in both the preconditioning and receiving phases. No treatment effects were also detected (P > 0.44) for daily TMR intake in any of the phases. Overall feed efficiency did not differ between BAS and CON calves (P > 0.54). No treatment effects were detected (P = 0.98) for plasma concentrations of cortisol. A treatment × day interaction was detected (P < 0.001) for plasma haptoglobin concentrations, which was greater (P < 0.01) in CON on day 3 and 7 vs. BAS calves. Therefore, multiple applications of BAS mitigated an acute-phase response associated with accumulative stress caused by weaning, transport, and vaccination.