Bull management prior to the breeding season

Glenn Selk, Oklahoma State University Emeritus Extension Animal Scientist


Before the breeding season begins, a few simple management procedures involving the bulls can increase the likelihood of a high pregnancy percentage among the cows. Any rancher that purchases a young, highly fitted or conditioned bull should plan to gradually reduce the fleshiness of the bull before the breeding season.  To let these bulls down, it is a good practice to start them on a ration that is not too dissimilar to the one to which they have been accustomed, but that the concentrate portion is 60 to 70 percent of their previous intake.  The amount of grain can be reduced at the rate of about 10 percent per week until the desired level is achieved.  At the same time, substitutions should be made in the form of quality forages--such as high quality grass hay or alfalfa hay.  Ideally, this letdown should be completed prior to the time bulls are turned out. 


Dramatic nutritional changes can have an adverse effect on semen production, so it is important that these ration modifications be done gradually.  Producers need to try to keep the total diet of these young bulls at, or near, 12% crude protein.  Therefore the forage needs to be excellent quality.  Allow the change of diets to take place gradually, instead of allowing a rapid condition and weight loss during the first of the breeding season, which could be reflected in a reduced calf crop next year. 


Other bull management strategies include the following:


1)      Check the feet and have hoof trimming completed at least 30 days prior to the start of the breeding season to avoid lame or sore-footed bulls at the important beginning of the breeding season. 

2)      In multi-sire pastures, make certain that the bulls that will be pastured together have been in a common trap or pasture prior to the breeding season.  Bulls WILL establish a social hierarchy.  It is better to get this done before the breeding season begins rather than wait until they are first placed with the cows.

3)      Put young bulls with young bulls and mature bulls with mature bulls.  Mixing the ages will result in the mature bull dominating the younger bull completely, and in some instances causing a serious injury.   If the plan is to rotate bulls during the breeding season, then use the mature bulls first, and follow with the yearling bulls in the last third of the breeding season.  In this way, the young bulls will have fewer cows to settle, and will be 1 - 2 months older when they start breeding.


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