may become less willing and able to inseminate females. Specific nutrient deficiencies may result in lowered physical ability to mate in addition to specific effects noted by Hurley and Doane (1989).

It should be noted that the negative effects of malnutrition are more evident in the young male than in older animals. The mature male is remarkably resistant to nutritional stress, and infertility problems of nutritional origin are not often encountered. Both young and mature males frequently lose weight during the breeding season resulting from both decreased food consumption and substantially increased physical activity. Thus, bulls should be in good body condition at the beginning of the breeding season to provide energy and protein reserves for use during breeding.

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