Читать книгу Bovine Reproduction - Группа авторов - Страница 70

Since one bull may be responsible for breeding twenty (by natural service in one breeding season) to thousands (artificial insemination) of females, bull fertility is critically important. Although sterile bulls (total inability to reproduce) are uncommon, there can be a wide range in bull fertility, particularly in the absence of selection for fertility [1]. It is well established that a bull's testes must be 2–6 °C cooler than core body temperature for fertile sperm to be produced; consequently, increased testicular temperature, regardless of cause, reduces semen quality [2]. Although the underlying cause of infertility in bulls is frequently unknown, we speculate that it is often increased testicular temperature.