A dairy farmer speaking with ABC Rural reporter Michael McKenzie the other day didn’t really get to explain himself after suggesting that using bulls rather than artificial insemination was linked with inductions.
For decades, it’s been pretty standard practice on Australian dairy farms to use straws of frozen sperm rather than natural matings. Artificial insemination (AI) doesn’t hurt and using frozen semen allows farmers to select traits from the best bulls around the world.
Each bull is given a numerical rating for the characteristics they pass on to their daughters. The scope is amazing – everything from teat length through to temperament is measured – and we can use that information to select sires that will correct problems in the herd. If, for example, we have quite a few cows with short teats, we can choose a mate whose daughters tend to have unusually long teats.
In this way, our cows get naturally healthier and stronger, generation after generation. Better legs and feet means less lameness, while better udders means less mastitis (oh, and susceptibility to mastitis itself is on the list, too!).
There is a drawback though. People are rarely as good as bulls are at detecting when a cow is fertile. Bulls curl back their lips to seemingly drink in the pheromones undetectable to humans while frozen semen may also be less potent than that of a bull.
For this reason, most farmers who aim to have the herd calve over just a few weeks use AI followed by a short period of natural matings with “mop up” bulls.
The farmer was trying to say that he used just the AI, effectively mating his cows over less time. That’s his choice but I can’t see how it has any impact on whether a farmer uses drugs to induce an early calving. If you want a lot of calves in a short time, feed the cows well, choose sires well ranked for fertility and pull the bulls out early.
As you can see from other Milk Maid Marian blog posts, I believe inductions for any reason other than the welfare of the mother cow should be banned. I am not alone – most dairy farmers detest it. The practice is already almost wiped out, with only 1.58 per cent of Australia’s dairy cows induced in 2010. Still too many but a long, long way off the epidemic suggested in media reports.