150 Administering an appeasing substance to Bos indicus-influenced beef cattle at weaning and feedlot entry

摘要

Bovine appeasing substance (BAS) is expected to have calming effect in cattle experiencing stressful situations, including weaning and feedlot arrival. In Exp. 1, 186 Bos indicus-influenced calves (73 heifers, 133 bulls) were weaned at 211 ± 1 d of age (d 0). Upon weaning, calves were ranked by sex and body weight (BW), and assigned to receive BAS (Nutricorp, Araras, SP, Brazil; n = 94) or water (CON; n = 92). Treatments (5-mL) were topically applied to the forehead of each animal. Calf BW was recorded and samples of blood and tail-switch hair collected on d 0, 15, and 45. Calves that received BAS had greater (P < 0.01) average daily again (ADG) from d 0 to 15, and BW on d 15 compared with CON. Overall ADG and BW on d 45 were also greater (P < 0.05) in BAS vs. CON. Plasma concentrations of haptoglobin were less (P < 0.01) in BAS vs. CON cattle on d 15, whereas cortisol concentrations in plasma and tail-switch hair did not differ between treatments (P > 0.16). In Exp. 2, 140 B. indicus-influenced bulls (~27 mo of age) were transported from a cow-calf ranch to a commercial feedlot (d -1), and maintained on a single pasture for 24 h. On d 0, bulls were ranked by BW and assigned to receive BAS (n = 70) or CON (n = 70) as in Exp. 1. Bulls receiving BAS had greater (P = 0.04) ADG from d 0 to 15, but less (P < 0.01) ADG from d 15 to 45 compared to CON. No other treatment effects were detected (P > 0.18). Therefore, BAS administration to beef cattle at weaning or feedlot entry had immediate benefits to ADG, which were sustained for 45 d in weaned calves but not in feedlot cattle.