Last week, I explored the topic on nutritional causes of infertility in cows. The article elicited a lot of feedback from readers. Today’s article is based on feedback from one of the readers, Mr Chemigin, a farmer from Nandi County.
Mr Chemigin said he has two cows that have not been able to conceive for the last seven months. He described to me his feeding regime, which includes adequate mineral supplementation, maybe ruling out the nutritional cause that I had discussed.
I couldn’t point out the probable cause of the “infertility” in the two cows until he said he has a bull that he uses and therefore he too ruled out missing the heat signs as a cause of his farming problem.
Although I may not be able to make a definitive diagnosis from what Chemigin presented, I can list use of the bull as a probable cause. It must be understood there are many other causes of infertility in cows ranging from diseases, genetics, anatomical deformities and poor husbandry practices.
For reproduction in cows, there are two options – the natural method where a bull is used and Artificial Insemination (AI) where collected semen is used.
Artificial Insemination has many advantages over the use of a bull. AI is cost effective and efficient. When a bull is used, it deposits more semen than is theoretically needed for a pregnancy— the rest goes to waste and my genetics lecturer used to tell us that nature is wasteful.
The natural mating process is a high energy, physically draining exercise for the bull, thus it limits the number of females a bull can serve in a day and subsequently its whole lifespan.
When to call a vet
On the other hand, when this semen is collected, a superior bull’s semen can be used to serve many females in different geographical places at the same time, thus fastening the process of breed improvement.
Semen from a good bull can be stored for long, making it available to serve more cows than it would have through the natural insemination. The cost of keeping a bull purely for breeding has been shown to be hundreds of times higher compared to when AI is used.
Testosterone-filled bulls can pose a risk on the farm during handling, and AI reduces this risk not only to people on the farm but also other animals, not to mention other additional handling costs that would come with the housing and purchase of handling tools such as nose rings. Mating relatively larger size bulls than females can result in accidents and injury to either the cow or the bull.
Nonetheless, it must be noted that unlike in natural mating, where AI is used it is very crucial for the farmer to keenly be on the lookout for the signs of heat and to call in an inseminator at the right time, failing which the cow may not conceive.
In this sense, this method can be said to be laborious. The semen also needs to be stored well so that it does not go bad. Any discontinuity on the cold chain can easily kill the semen.
Now the reason I think Chemigin’s problem could be related to his bull is that the use of bulls comes with the risk of spread of venereal diseases. Such infections are normally carried by bulls and spread during mating.
Most of these diseases can cause infertility in cows. They can also cause early embryonic deaths, which will be manifested by repeat breeders. These diseases are very common where one bull is shared across farms.
But for a confirmatory diagnosis on the exact cause of infertility in your cows, you need to call in your vet to do a thorough examination of the cow.
The writer is the winner of Vet of the Year Award 2016; he works with the Kenya Tsetse and Trypanosomiasis Eradication Council
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