Bull Breeding Soundness Examination

Did you know 20% of bulls are sub-fertile?

Screen your bull stud pre-breeding and avoid using sub-fertile or infertile bulls.

Normally fertile bulls: are defined as being capable of impregnating >95% of fifty normally cycling cows/heifers in a 9-week mating period.

Sub-fertile bulls: It has been found that around 20% of bulls are incapable of doing this i.e. they are sub-fertile. 'Sub-fertile' means that although the bull will get cows pregnant the rate of conception to him is too low to achieve pregnancy in >95% of fifty normally cycling cows in a 9-week mating period. The practice of rotating bulls around mating groups will mask the presence of sub-fertile bulls making them very difficult to detect by the farmer.

Infertile bulls: A few bulls are infertile which means that they are incapable of getting any females pregnant and they are more often detected by the farmer because all females mated are seen to return to oestrus.

Sub-fertility or infertilty is caused by either phyiscal defects in the bull limiting his ability to mate frequently or poor quality semen.

Bull Breeding Soundness Examination

Over the last decade in the UK routinely examining bulls for breeding soundness has become increasingly popular with many herds now screening all bulls before each mating period to ensure maximum pregnancy rates over a short time period by not using bulls that are identified as sub-fertile or infertile. Of course individual bulls whose fertility performance is suspect can also be examined to assess their breeding soundness.

We now offer this service which involves a full phyiscal examination of the bull and his internal and external reproductive organs followed by semen collection using an electro-ejeculator and evaluation of the semen. Each bull then receives a certificate outlining the findings and whether or not he is of normal fertility and suitabled for breeding. This allows the farmer to make sound decisions on which bulls to use.

Examination of the bull stud about one-month before the mating period is recommended. The factilites required on farm are a decent handling facility with a crush that has a side openng allowing access to the bulls prepuce and a power source and 'bench space' nearby to set up microscope etc.