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How many stock bulls do you have?

How many stock bulls do you have?

Approaching mid-way point in the breeding season, it's important to not lose sight of the targets. "Easier said than done with farmers weary from a busy calving season, an intensive start to early breeding and getting silage sorted in the last few days", says Stuart Childs, Teagasc Dairy specialist

The objective, depending on the calving pattern in 2022, should be to have 100% of cows that are being bred in 2022 within 6 weeks or at a minimum 7 weeks. This will improve the calving pattern for next year which will mean there will be more cows ready for breeding next year than this year so this objective is an important one.

The risk that exists right now is that with dairy breeding winding down now, people will take the eye off the ball and foot off the pedal with regards to breeding intensity. There are still plenty of cows to be bred between repeats and cows still not bred.

Role of Beef AI

The role of beef AI in dairy herds cannot be underestimated. Calving ease, gestation length, and quality of the calf are significant benefits of beef AI but the biggest advantage many forget is the pressure that it lifts off of bulls on the farm.

There is a complete over-expectation of what bulls are capable of handling. A mature bull is capable of serving 3 cows every 2 days or approximately 30 cows in 3 weeks. If there is more than 1-2 cows on heat on any given day, the bull will be overworked. The result of this will be a drawn out calving pattern for the 2nd 6 weeks.

Another key figure to bear in mind is that every extra 3 weeks of AI completed reduces bull requirement by half.

100 dairy cow example

As an example, if we take an average 100 cow dairy farmer that has identified 10 cows that will not be bred, submitting 80% of the cows to be bred in 3 weeks at a 60% conception.

  • 90 cows to be bred.
  • 80% submitted.
  • 50% conception to service.
  • 36 cows in calf after 3 weeks
  • 63 cows in calf after 6 weeks
  • 77 cows in calf after 9 weeks
  • 84 cows in calf at the end of a 12 week breeding season.

Bear in mind that if you have cows that you have decided not to breed, your bull does not know this so he will serve them also if they come in heat. This creates extra work for him

If there is only one mature bull on the farm then the earliest that the bull can be left off is week 8 because the bull is going to serve your 10 cull cows also. Anything earlier than this and the bull will be extremely busy and under severe pressure to deliver.

In short, just because you have finished your dairy AI doesn’t mean you finish AI. You should continue to use beef AI until you have at least reached the number of cows that your bull will be capable of managing. If you have a young bull, this figure is half that of a mature bull so keep up your AI!

You might also like to read Using beef AI on the dairy herd 

The Teagasc Dairy Specialists issue an article on a topic of interest to dairy farmers every Monday here on Teagasc Daily. Find more on Teagasc Dairy here