After-hours/Emergency Phone: 07 573 7606

07 573 7606

Te Puke Veterinary Centre Ltd

Bull Fertility

Bulls are assumed to be fertile... – Wrong assumption!

Approximately 10% of bulls are subfertile or infertile, and this can have devastating consequences. The causes of infertility are varied, but regardless of the cause, if a bull or team of bulls are infertile there is no way the cows will get in calf.

Using plenty of bulls provides safety in numbers, as to some extent fertile bull(s) can cover the infertile ones. However if a behaviourally dominant bull is the infertile one, you are only using one bull or if bull power is down in general then a worst case scenario can eventuate. The bulls are the last chance for any non-pregnant cows to conceive so it is important to get your bull management right.

 

Causes of Bull Infertility

Bull infertility can result from poor sperm quality, behavioural issues or sickness and disease. Sperm quality is affected when the bull is sick, immature or aging.

Behavioural issues, such as unwillingness to mount or excessive fighting/aggression may limit a bull’s ability to mate normally and peacefully. Other sickness, deformity or disease can have major impacts on bull fertility. Lameness is one of the biggest problems. Hoof or leg damage can affect a bull’s ability or interest in mounting. Systemic diseases affecting fertility such as Bovine Viral Diarrhea (BVD) can also become issues. Deformities such as a corkscrew penis can be invisible until the bull is seen mounting.

 

Finding infertile bulls

Most infertile bulls can be identified with a thorough physical examination, blood sample and a semen sample.  If your bulls arrive on the property untested, or you are unsure of the quality of the bulls you have, it is important to get them checked and replaced if required early in the season. If you require bull fertility assessment, please let us know well in advance of when the bulls are required to join the cows.