Dear daktari, I am a dairy farmer but recently I got a bull calf from one of my cows and I am tempted to keep it. It is such a nice bull calf, I plan to use it for Artificial Insemination on my farm. What are the characteristics of a good bull calf for breeding purposes?
[Humphrey Kariuki, Embu]
Dear Mr Kariuki. Thank you for your inquiry. Now before I dive deep into your question, let me inform you that if you choose to keep this calf as you have indicated, be informed that you will have the challenge of inbreeding on your farm. Inasmuch as Artificial Insemination seems to have many advantages compared to natural mating, bulls are still in use in many farms. But it should be highly controlled to avoid spread of diseases or undesirable genetic traits. Whether using Artificial Insemination (AI) or natural mating, it is worth noting that bulls (sires) will always provide the greatest proportion of genetics of the subsequent calves. If you want calves with desirable traits, you need a sire that has equally desirable genetics. There are many factors to consider and we cannot exhaust them in this article. I will address a few factors.
This should be the first factor to check out. It refers to the anatomical structures in a bull and should be the first thing to evaluate whenever you are selecting a bull especially for the natural mating system. A bull that has structural abnormalities will not perfume as expected. Anatomical correctness include a well-structured shoulder, well-formed front and hind legs. The back should also be strong, wide and flat. A physical examination should also be done for eyes, teeth, mouth, gait and general body condition.
Breeding soundness examination
A veterinarian will examine the bull’s reproductive organs, measure the circumference of the scrotum and microscopic analysis of the semen for concentration, movement and shape or morphology. A bigger scrotum correlates with production of more semen and it will sire bulls with similar genetics. The scrotal circumference should be more than 34 centimetres. In farms where breeding is taken seriously, this examination is normally done annually and forms the basis for culling.
However, as a farmer you can also carry out basic breeding soundness examination by looking at the reproductive organs for any visible abnormalities like wounds, malformations, warts and inflammations. Any strange sign should be an alert that the bull is not sound for breeding purposes.
Libido or sex drive
If a bull passes physical examination and breeding soundness examinations it must also pass the sex drive test. There is no other way of measuring this apart from observing how the bull serves cows. It is during mating that a farmer can also detect physical abnormalities.
Records offer a very good reference point for breeding fitness. This should include records of the bull’s parents, relatives and progeny. This will give you an indicator of how the bull and its progeny will perform.
[Dr Othieno is a veterinary surgeon and head of communications at the Food and Agriculture Organisation of the United Nations (FAO) Kenya. The views expressed here are not necessarily those of FAO]