Managing reproduction effectively to achieve optimum fertility is essential to the running of a profitable cattle enterprise.

Although few bulls are sterile (incapable of successfully impregnating cows), sub-fertility is relatively common.

It is not unreasonable to expect a fully fertile stock bull running with 50 normally cycling, disease-free cows to achieve a 90% pregnancy rate after a nine-week serving period (three heats).

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Almost one in three stock bulls currently in use fail to achieve this target, taking a longer time to get cows pregnant, which has a profound effect on profitability.

Appropriate action

A bull breeding soundness examination carried out by your veterinary surgeon, aiming to identify individual infertile and subfertile bulls in advance of the breeding season, allows appropriate action to be taken and will frequently prove to be a very worthwhile investment.

  • Physical examination: this begins at a distance assessing size relative to age, body condition, conformation, locomotion (lameness) and noting signs that might be consistent with the presence of any infectious or contagious disease. A review of vaccination (BVD etc) and other treatment history, for example, dosing should be checked.
  • Libido and serving assessment: watching the bull’s behaviour whilst working allows an assessment to be made of his libido and of his ability to serve.
  • Semen test: the bull may appear physically normal and have a good libido but still be infertile. Your vet can perform semen collection and examination - this is a vital part of assessing your bull.

    • The reasons a bull fails breeding soundness examination are of course many and varied.

    Discussing the bull’s performance with your vet and having them perform the exam is time well spent.

    Craig McAlister MRCVS, Parklands Veterinary Group, Northern Ireland