Work

PSI-18 Effects of a bovine appeasing substance applied at estrous synchronization on stress and reproductive performance.

Year: 2025

Type: article

Abstract: Management practices induce stress, resulting in impaired growth and reproduction. Therefore, techniques to mitigate stress and its effects must be investigated. One strategy includes administration of a synthetic maternal bovine appeasing pheromone studied to have calming effects on cattle. The aim of this study was to evaluate the effects of a bovine appeasing substance (BAS) applied at estrous synchronization on reproductive stress and pregnancy rates. Crossbred beef cows (n = 131) were stratified by body weight (BW, 385 kg ± 0.53 kg), body condition score (BCS), and post-partum interval, then allocated to 1 of 2 pens. Pens were assigned randomly to treatment 1) administered BAS topically to the nuchal skin (5 mL) and poll (5 mL) at estrous synchronization (BAS; n = 71), or 2) control where BAS was not administered (CON; n = 60). BW was recorded on d 0, 7, breeding (d 9 and 10), and 106 to calculate change in BW. BCS was recorded on d 0 and d 106. Estrous synchronization and breeding protocols followed a 7-day-CO-Synch + CIDR combined with heat detection and timed artificial insemination (AI). Blood subsamples (BAS, n = 20; CON, n = 20) for serum cortisol analysis were collected on d 0, 7, breeding, and 106. Pregnancy was determined on d 106 via transrectal ultrasonography. Cortisol and change in BW were analyzed using the GLIMMIX procedures of SAS while GENMOD was used for AI and pregnancy variables. Significance was declared at P ≤ 0.05. There were no effects on BW for treatment by day interaction, however, BAS tended to be heavier compared to CON (P = 0.08) at breeding. There was an effect for treatment (P = 0.03), day (P ˂ 0.01), and their interaction (P = 0.03) for serum cortisol. At breeding, animals experienced greater cortisol concentrations of 11.68 ng/mL compared to d 0, 7, and 106; however, there were no differences in cortisol concentrations between treatments at breeding (P = 0.28). Overall, 51.18% of animals were open while 48.82% were bred, of those, 28.71% were bred via AI and 61.29% were bred via NS. In CON, 18 were bred via AI compared to 6 in BAS while 25 in BAS were bred via NS compared to 13 in CON (P ˂ 0.01). Previous research has reported a reduction in stress when a bovine appeasing substance was applied. In our study, applying a bovine appeasing substance at estrous synchronization did not reduce stress at the time of AI and did not impact reproductive success.

Source: Journal of Animal Science

DOI: 10.1093/jas/skaf300.433