Research at Kansas State University has illustrated that young "gain-tested" bulls have normal fertility and libido when allowed to return gradually to moderate fleshiness and hearty physical condition before the breeding season. In fact, many performance-tested bulls are returned to the owner's ranch after the gain test in order that they be allowed to be properly conditioned before the sale date. Test station sales usually offer bulls that completed their gain test about 6 months previously.
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 they have been accustomed to but that 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 light, bulky feeds--such as oats 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. Allow the change to take place gradually instead of allowing a rapid condition and weight loss which could be reflected in a reduced calf crop next year.
If a young bull is coming off of a high energy diet (i.e. gain test), an example feeding schedule would be as follows:
% of lb. for lb. for
Week Type Body wt. 1000 lb. bull 1500 lb. bull
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1st bull test 1.5 15 23
hay 1.0 10 15
2nd bull test 1.0 10 15
hay 1.5 15 23
3rd bull test 1.0 10 15
hay 1.5 15 23
4th bull test .75 7.5 11
hay 1.75 17.5 27
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Continue feeding the grain mix to the young bull during the breeding season if at all possible.