Effects of Temperament and Acclimation to Handling on Reproductive Performance of Bos taurus Beef Females06 February 2013
A team of researchers at Oregon State University have concluded that aggressive cattle have impaired reproductive performance.
Two experiments evaluated the effects of temperament and acclimation to handling on reproductive performance of Bos taurus beef females. In Exp. 1, 433 multiparous, lactating Angus × Hereford cows were sampled for blood and evaluated for temperament before the breeding season. Cow temperament was assessed by chute score and exit velocity. Chute score was assessed on a five-point scale according to behavioral responses during chute restraining.
Exit score was calculated by dividing exit velocity into quintiles and assigning cows with a score from 1 to 5 (1 = slowest, 5 = fastest cows). Temperament score was calculated by averaging chute and exit scores. Cows were classified for temperament type according to temperament score (? 3 = adequate, > 3 = aggressive).
- Plasma cortisol concentrations were greater in cows with aggressive vs. adequate temperament.
- Cows with aggressive temperament had reduced pregnancy (95% = adequate and 89% = aggressive) and calving rate (92% adequate and 85% aggressive) and tended to have reduced weaning rate com pared with cows with adequate temperament.
- Hence, pound of calf born per cow was reduced and pound of calf weaned per cow (491 pounds = adequate and 455 pounds = aggressive) tended to be reduced in aggressive cows.
In Exp. 2, 88 Angus × Hereford heifers (initial age = 206 days) were weighed (day 0 and 10) and evaluated for temperament score (day 10). On day 11, heifers were ranked by these variables and assigned to receive or not (control) an acclimation treatment. Acclimated heifers were processed through a handling facility three times weekly for four weeks (Mondays, Wednesdays and Fridays), whereas control heifers remained undisturbed on pasture.
- Puberty was hastened in acclimated heifers (60%) compared with control (38%).
Results from this study indicate that B. taurus beef cows with aggressive temperament have impaired reproductive performance compared with cohorts with adequate temperament, whereas acclimation to human handling after weaning hastens reproductive development of replacement heifers.