A bull with a docile demeanour has a high probability of fathering a docile progeny, which will be easy to handle. [Courtesy]

Dear Dr Othieno, Thank you so much for your informative articles on various animal health topics. I plan to acquire a bull for breeding purposes. I know experts advocate for Artificial Insemination (AI), but I have my reasons for opting for a bull instead. I would like to know what I should consider in selecting a bull for my herd.

Amoding Jesse, Teso North 

Thank you Jesse for reading the Smart Harvest and for your good question on breeding bull selection. Although most cattle farmers prefer to use AI based on its many advantages, many more still use a bull. After all, even the semen we use in AI comes from a bull. So, it is important to have some basic knowledge of what to look at in selecting a bull for breeding purposes.

Using AI is relatively cheaper compared to feeding and maintaining a bull on the farm for breeding purposes. It is expensive and when you consider that this will not be for long as you have to change the bull to avoid inbreeding, which has many disadvantages. Many farmers rely on the bull because they do not have access to AI services.

When selecting a bull, your breeding objectives must be very clear. The objectives will be informed by the traits of economic importance, the market preferences, your production targets and your current herd composition and performance. This will enable you to pick a bull with the highest probability of attaining your goals.

Here are a few traits that you should be on the lookout for when selecting a bull.

Temperament - A bull with a docile demeanour has a high probability of fathering a docile progeny, which will be easy to handle. Livestock geneticists have various ways of measuring temperament. Temperament is an important trait because it is highly heritable. Calves should be calm. Nervous cattle become stressed, eat less, are more prone to sickness, and perform poorer.

Scrotal circumference or size – This is measured in centimetres. Normally, the minimum is taken at 32cm, but the best is 34-36cm for a two-year-old bull. Closely tied to the scrotum is the prepuce or the sheath – it should not be pendulous but well formed and tight.

Physical Wholesomeness – the bull should have well-formed legs and feet. This fitness will determine the bull’s serving abilities later in its reproductive life. A bull must be physically fit to mate. Sound feet and legs, particularly hind legs, are critical for the bull’s prolonged service life.

Semen quality – You will not be able to assess this as a farmer, but a veterinary doctor can do a microscopic laboratory examination of the semen for quality traits like motility, colour and quantities.

When buying a bull for breeding purposes, insist on the reproductive records, which will help give a glimpse into its ancestral lineage to be able to extrapolate what kind of progeny the bull will produce. Also, remember that the bull breed is a critical consideration. One way to produce heavier calves with improved carcass traits is through hybrid vigour. Hybrid vigour is the increased performance or expression of a trait resulting from crossbreeding.

- Dr Joseph Othieno is a veterinary surgeon and currently the head of communications at the Food and Agriculture Organisation (FAO) of the United Nations, Kenya. The views expressed here are not necessarily those of FAO but his own.