The spring breeding season is fast approaching and we all need to have the herd bulls in sound and good condition before being placed with the cow herd. Bulls should be evaluated for breeding soundness at least 30 days before the breeding season. This will give you time to buy a replacement(s) if you have a bull(s) of questionable breeding ability.
This evaluation should involve a physical examination which would include: feet, legs, knees, and shoulders - any abnormality that will limit the bull's ability to travel will affect his breeding ability. Eyes should be checked for any problems. Bulls that are not sound due to sickness or injury tend to be dominated by other bulls - their breeding potential is then greatly reduced or is non-existent.
The overall body condition should be considered. A bull starting the breeding season in low body condition will lack the stamina to breed a large number of cows. If the bulls are thin, they may need to receive 20 pounds or more of a high energy feed. Be sure to start the bulls gradually and move them up to the desired amount. Dr. Glen Selk has published a paper on titled "Management of Beef Bulls" that is available from Oklahoma State University Extension. That paper addresses the nutritional management of your herd bulls. It is an excellent reference paper to have on file.
If the bulls are sound and in good body condition, the next examination should be done by your veterinarian and will include examination of the reproductive tract and a semen evaluation. It is very common to have a bull that is sound in every way producing semen of unsatisfactory quality or that is at least questionable in quality.
For the smaller herds that are using a single bull, the above bull problem can be a disaster! No calf crop! Even if the smaller breeding units are using multiple sires and the dominant bull is infertile, the calf crop can be adversely affected. The money spent on a breeding soundness check is money well spent.
The following survey of 10,940 bulls found 20% (2,266) to be questionable or unsatisfactory for breeding. This survey was done by Colorado State University.
Another question that often comes up is age and its effect on the breeding. Fertility of bulls is greatest between two and four years and tends to decrease with age. Dr. T. D. Rich published an interesting table (1950 - 1959) in a paper that tracked the lifetime breeding record of an Angus bull. As we know, as with all things, variation always exists but this record gives a good idea of how age influence on breeding.
This bull shows a steady decline in performance at about seven years of age. This will give some guidelines that we might keep in mind. The older bulls can be held in reserve or used in a rotation during the breeding season.
Be sure to use bulls in a manner that would not allow an older, lower performing bull to be used where he can be dominate to the younger higher performing bull. Rotate your bulls by age as much as possible. Work the younger bulls - pull them - work the older bull. Plan your program!