Scrotal circumference at weaning in beef bulls and subsequent ability to pass a breeding soundness examination as a yearling

Abstract

Identifying bulls at weaning with higher likelihood of
passing a breeding soundness examination as yearlings may
improve management options to optimize production efficiency.
The objective of this study was to evaluate the effect of weaning scrotal circumference and other factors collected at the time of weaning on the likelihood of passing a breeding soundness examination as a yearling. Data, at both weaning and time of breeding soundness examination, were collected from 1 operation (n = 466 bulls). A logistic regression model was used to evaluate the potential associations of relevant factors (actual weaning scrotal circumference, adjusted weaning scrotal circumference, weight per day of age at weaning, scrotal circumference per day of age at weaning, weaning weight, and breed) on the probability of passing a breeding soundness examination as a yearling. Overall, 92.3% of bulls passed the yearling breeding soundness examination on first evaluation. Weaning scrotal circumference was the only factor of those evaluated associated (P < 0.01) with the probability of passing the breeding soundness examination. No significant differences were found between the categories of weaning scrotal circumference. In the future, more research needs to evaluate predictive model development for weaning scrotal circumference and ability to pass breeding soundness examination.