By Joyce Voogt, LIC International Technical Manager
Joining season is not over at the end of artificial insemination (AI) on most farms. Ensure that your natural mating service bulls are also in peak physical condition before they head out into the field to maximise your chance of successful mating.
1. Have enough of the right players
To calculate the number of bulls required, firstly calculate the number of cows still left to get in-calf after AI.
You’ll need one 2-year-old bull in the paddock for every 30 of these non-pregnant cows with a minimum of two bulls. Double this number of bulls to get your two teams.
Remember you’ll need extras to cover synchrony returns; or you could resume AI between days 18-24 post synchrony to cover returns.
If your numbers are inadequate consider extending AI for a week or two. Talk to your vet about options.
2. Picking the team
Source enough fit, well-conditioned bulls; and reject scruffy characters.
If in doubt get them health checked; you can’t afford a dud.
Talk to your vet about required testing and vaccination regimes for your bulls.
3. Watch the players
Are they getting the job done?
Plenty can go wrong with bulls, so regular observation of them working is essential to identify problems early.
If he’s not up to the job, we recommend removing and replacing him as soon as possible.
4. Rotation policy
Rotate your bull teams regularly (eg. every 48 hours) to help keep your bulls interested in the cows and to optimise their performance.
These resting players still need high quality feed; so make sure your bull paddock has adequate feed.
5. Save their feet
Lameness is serious and a waste of a good player! Prevention strategies are important.
Leave them in the paddock, don’t let them onto the yard, avoid long walks on rough tracks, and don’t hassle them with the dogs.
6. Safety first
Make sure that your staff are trained to work with bulls.
If there are any bulls that are aggressive, replace them to reduce the risk of injury to staff and cows.
7. After-match review
Use pregnancy testing information to assess how the natural mating period went: early-aged pregnancy testing generates in-calf rate graphs in your InCalf Detailed Fertility Focus Report that will show you how things went through the whole of mating.
Your vet can help you choose PD dates for your individual herd that will provide sufficient information to generate this version of the report.
For additional support with bull management while they’re already in the herd, refer to Dairy Australia’s InCalf Book: Section E, Bull Management, page 113.
