Smidt W J
Gezondheidsdienst voor dieren in Oost-Nederland, Deventer.
Tijdschr Diergeneeskd. 1994 Jan 15;119(2):33-5.
Penis extension (emissio penis) depends on the length of the penis and on the relaxation of the retractor muscle of the penis. When the relaxation is insufficient, penis extension is at its smallest just before intromission takes place. In severe cases this can lead to impotence (impotentia coeundi). Whether this occurs depends on the animal's libido and mating behaviour and on external factors. Genetic factors play a role in emissio penis.
阴茎伸展（阴茎射精）取决于阴茎的长度以及阴茎牵缩肌的松弛程度。当松弛不足时，就在插入前阴茎伸展最小。在严重情况下，这可能导致阳痿（性交不能）。是否会发生这种情况取决于动物的性欲和交配行为以及外部因素。遗传因素在阴茎射精中起作用。
