The bull as a source of trichomonosis and lumpy skin disease: An African perspective

Abstract

The use of bulls in breeding herds is regarded as a practical, labour-efficient way of producing a calf crop. However, the risks of a poor crop due to unsatisfactory performance of bulls are significant. The causes of sub- or infertility of the bull are classified under the headings Impotentia generandi, referring to a lack of fertile semen, and Impotentia coeundi, or an inability to mate naturally due to physical causes or a lack of libido. Prior screening of bulls to reduce the risks is therefore prudent. Most of the causes of infertility can be detected in a systematic examination of the bull and a representative semen sample. The bull in which no causes of infertility are identified during such an examination is termed breeding sound, which is not a guarantee of fertility but implies a reduced risk of infertility.