Running the bulls

animal health

Mating time is just around the corner –  Anexa FVC Gordonton veterinarian Michael Shallcrass shares some advice for farmers.Michael Shallcrass

For most farmers the bull mating period has been reduced to four or five weeks, which means that cows not yet pregnant at the end of AB may only get one chance with the bull before the end of mating. It is therefore vital that you plan and execute your bull mating period as well as possible.

Bulls should come from a reputable source and arrive on farm several weeks before they start work to give them time to settle in and any issues to become apparent. Insist on bulls that have been BVD tested and vaccinated, and in an ideal world they should also be vaccinated against lepto and blackleg.

If a bull gets lame he won’t work as hard, and if he gets sick or has a temperature his sperm quality will drop. It takes up to 70 days for new healthy sperm to be produced and you don’t have time to wait for that, so any bull with any problem needs to be replaced as soon as possible. Bulls should be trained to stay in paddocks or at least not to come onto concrete yards; yes it’s more work, but it will greatly reduce the risk of them becoming lame.

Bull power is another factor that needs to be considered. Historically, a long eight or ten week bull mating period could compensate for low bull numbers or poor performers, but with shorter mating periods this is no longer the case. For a 300 cow herd with average repro performance, you should have six bulls in with the herd at any one time (usually two teams of three). There should also be an equal number of spare bulls so they can be regularly rotated to keep them keen. This means that there should be at least 12 bulls on farm from about the middle of October through to around Christmas time.

We know that bulls are a pain and that they fight and dig holes and break fences, but if you have enough of them and manage them well, then you can see a big improvement in your conception rates over that period.

Right now is an excellent time to talk to your vet or consultant and discuss your bull management plan for the upcoming months.

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Number 8 Network - a community website for the rural areas northeast of Hamilton, NZ, is run by Gordonton journalist/editor Annette Taylor.

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