Why Bull Breeding Soundness Matters: Insights for Dairy and Beef Producers

As the cornerstone of any successful breeding program, bull fertility has a direct impact on calving rates, herd productivity, and ultimately, profitability. Despite this, the fertility and breeding readiness of bulls is often assumed rather than assessed. Breeding Soundness Evaluations (BSEs) provide a structured and science-based way to ensure bulls are capable of performing when the pressure is on.

A large study (Hancock et al., 2016), focusing on bulls used in the Southern Australian dairy industry, revealed that 20 % of bulls tested were sub-fertile or infertile at the time of a pre-mating evaluation - that is 1 in 5 bulls!  The also identified a number of key risk factors for bulls being at high risk of infertility that included age with bulls over 4 years of age being twice as likely to be classified as high risk than younger bulls and bulls with swollen joints at the BSE were twice as likely to go lame during mating. These statistic should prompt all livestock producers—whether running dairy or beef operations—to reconsider how bulls are managed and selected ahead of joining.

A BSE is a comprehensive assessment that evaluates a bull’s:

• General physical soundness - including leg  and joint conformation
• Reproductive anatomy - internal and external reproductive organs
• Semen quality - sperm motility, morphology, and concentration A BSE will result in a bull being classified as a Pass, Conceded Pass or Fail. 

A bull that passes as BSE will be suitable for single sire mating and should be able to achieve a 90 % pregnancy rate in a mob of 60 cows over 9 weeks with 50 % conceiving in the first 3 weeks of mating.  A bull that achieves a “conceded pass” is often still OK to use in lower pressure mating systems and is not suitable for single sire mating - these bulls are not suitable for sale.

A BSE should be performed 6-8 weeks prior to joining, giving producers time to identify and replace any underperforming animals. All sale bulls should have a BSE prior to sale to avoid the potential legal and reputational minefield that can result the sale of an infertile bull!  Having the bulls yarded at this time before the breeding season also allows for vaccination with 7 in 1, Vibrovax and Pestigard along with a seasonal drench.