Are your bulls up to the job?
We have seen several bull team failures in the last few years, all of which were avoidable. For a hassle-free tailing up after artificial breeding (AB) has finished, please take heed of the following recommendations.
Ensure bulls arrive on farm a minimum of six weeks, but preferably two to three months, prior to intended use. This gives them time to settle, sort out any dominance issues and hopefully get over any new diseases they might become exposed to. This means at the very latest they should arrive on farm is at the start of AB.
Bulls should be blood-tested negative for bovine viral diarrhoea (BVD) antigen before arrival. Ensure you receive or visualise an official copy of the paperwork to confirm this. If you are unsure what the paperwork means then please give us a call. The fact that bulls have been vaccinated is not going to stop them introducing BVD to your farm. Given the emergence of Theileria in our area over the last few years it would be wise to enquire about the presence of this disease on the property of origin. If your herd is clear you don't want to bring it in. Equally you may have Theileria on your property (you might be unaware) and your bulls might be at risk of contracting this just before they are needed. The most useful precaution you can take is to treat bulls with Bayticol® Pour-On on arrival and at three weekly intervals until mating has finished. This will reduce the chance of them being bitten by infected ticks which spread the disease.
If not done so at farm of origin, which would be the preferred option, bulls should be vaccinated on arrival and one month later with BVD vaccine, preferably a combined BVD/IBR vaccine.
Bulls should be selected to be of an appropriate size for your cows or heifers and ideally have been fertility-checked to ensure they do not have any libido, conformational or semen defects that will render them infertile. If they have not been fertility checked this can be reasonably easy to organise once they have settled in to their mating groups.
Bulls should have a temperament that makes them easy and safe to handle.
How many bulls do you need?
For both yearling heifers and cows, use the 3% plus one rule. That is, if you have 100 animals to mate, then you will need three bulls and one spare.
Don't forget if bulls are being used following synchronisation, the ratio will need to be doubled, i.e. approximately one bull per 15 heifers.
It is a good idea to assume the worst and estimate that 50 to 60% of the herd is empty after six weeks of AB and calculate bull requirements based on this. Where possible, always have some spare bulls in case of breakdowns.
Talk to your vet if you have any queries or contact your clinic to ask about our Bull Fertility Testing service.