Читать книгу Bovine Reproduction - Группа авторов - Страница 217

The breeding act requires orchestration of interrelated simple and complex events. The bull must identify the female in estrus, approach, extend the penis, mount appropriately, achieve full erection, adjust his stance and posture, blindly search for the vulva with the penis, achieve intromission, make the breeding lunge, ejaculate, and dismount. The physical requirements are obvious and structural soundness is a necessary component of the successful breeding act.

In cattle the coital act occurs rapidly, with time from mounting to intromission and ejaculation generally less than 10 seconds and the time from intromission to ejaculation 1–2 seconds [5, 6]. Some non‐productive false mounts are expected, but excessive numbers may be associated with pathology of the axial or appendicular skeleton, problems with the erection process, impediments to penile protrusion and extension, or lack of innervation of the glans penis.

Following a successful breeding attempt the bull has a brief refractory period, the length of which varies among bulls and is likely affected by age, physical condition, and the presence of other bulls and females exhibiting estrus. For young physically sound bulls the refractory period may be only a few minutes and most bulls can be expected to copulate multiple times per day.