PSX-B-17 - Appeasing substance application at weaning enhanced growth and temperament of Bos indicus-influenced weaned calves in grazing system

The objective of this study was to evaluate the effects of a synthetic analogue of the bovine appeasing pheromone (i.e. bovine appeasing substance; BAS) on growth and temperament of weaned calves grazing Capim-Marandú (Urochloa brizantha cv Marandú). At weaning (d 0), 86 calves (47 steers and 39 heifers; Aberdeen Angus ´ Nelore; 8 ± 1 mo) were stratified by body weight (197.9 ± 24.9 kg) and randomly assigned to receive a single dose of BAS (n = 43; SecureCattle; Nutricorp, Araras, SP, Brazil) or saline (CON; n = 43; saline 0.9% NaCl). Treatments (5 ml) were topically applied to the nuchal skin area of each animal on d0. Body weight was collected on d 0, 8, 15, 51 and 100. Chute score (1 to 5; 1 = calm, no movement; 5 = violent and continuous struggling) and chute entrance and exit scores (1 to 3; 1 = slow; 3 = fast) were collected on d 3, 8, 15, 51 and 100. Scores were averaged across 3 trained technicians. Data were analyzed using the MIXED procedure of SAS. Calves assigned to BAS treatment had greater (P < 0.01) average daily gain (ADG) from d 8 to 15 (0.158 and -0.284 kg/d ± 0.07). Calves assigned to BAS treatment tended (P = 0.10) to have lower chute entrance score on d 8 and 51 and had lower (P = 0.02) chute exit score on d 8 than calves assigned to CON treatment. Additionally, calves assigned to BAS treatment tended (P = 0.07) to have lower chute score on d 8 when compared to calves assigned to CON treatment. The application of BAS at weaning improved calf ADG and improved calf temperament as observed by chute score and chute entrance and exit scores, suggesting that BAS application has calming effects.