Impotence in the bull: (1) Abnormal venous drainage of the corpus cavernosum penis

Abstract

Six young bulls (two Friesian, two Charolais, one polled Devon and one North Devon) that had never served successfully, showed good libido but lacked penile erection. In five of these bulls, the short flaccid organ was not protruded during attempted service. Radiography of the cavernous bodies and veins of the penis in the living animal demonstrated major venous drainage of the corpus cavernosum penis (ccp) by the dorsal venous system in all cases. This was not seen in normal bulls. Radiography and anatomical preparations of post mortem specimens showed that the ccp was drained by the dorsal venous system throughout the length of the organ. Proximally, the cavernous spaces of the ccp anastomosed with those of the corpus spongiosum penis (csp) and were drained by numerous small veins. Distally, a system of larger veins, not seen in normal bulls, drained into left and right sides of the dorsal venous system. No microscopical abnormalities of spermatozoa or of testes were found, but there was a marked lack of spermatozoa in the caudae epididymides. The evidence suggests that abnormal venous drainage of the ccp may have been the immediate cause of impotence in these bulls.

Stereological study of the elastic fiber and smooth muscle cell system in the bovine and buffalo penis

“…The fibroelastic penis of cattle and water buffalo is an organ of great interest in animal breeding, due to the outstanding role played by the fibrous component of the extracellular matrix of the CC for penile erection (Young et al 1977, Ashdown et al 1979. Tissues that are constantly submitted to tensile stretch, present a significant elastic system fibers (Cotta-Pereira 1976).…”

“…This explanation is overly simplistic, as the flaccid penis of live bull is very bendy, and it is necessary to generate a high pressure within the CC of the penis to allow the intromission (Ashdown et al 1979). Studies on the ruminant penile erection suggest that the blood carried to the CC of the penis through deep arteries is pumped from the crural region of the penis by ischiocavernosus muscle, so it increases the pressure inside the CC (Ashdown et al 1979).…”

“…This explanation is overly simplistic, as the flaccid penis of live bull is very bendy, and it is necessary to generate a high pressure within the CC of the penis to allow the intromission (Ashdown et al 1979). Studies on the ruminant penile erection suggest that the blood carried to the CC of the penis through deep arteries is pumped from the crural region of the penis by ischiocavernosus muscle, so it increases the pressure inside the CC (Ashdown et al 1979). The contraction of the ischiocavernosus muscle also makes pressure on the deep veins located in the penile root, so blood is pumped within a closed system into the cavernous spaces, increasing the pressure inside the penis (Ashdown et al 1979).…”

“…Studies on the ruminant penile erection suggest that the blood carried to the CC of the penis through deep arteries is pumped from the crural region of the penis by ischiocavernosus muscle, so it increases the pressure inside the CC (Ashdown et al 1979). The contraction of the ischiocavernosus muscle also makes pressure on the deep veins located in the penile root, so blood is pumped within a closed system into the cavernous spaces, increasing the pressure inside the penis (Ashdown et al 1979). The obstruction of the venous drainage helps to keep the pressure into the CC (Ashdown & Gilanpour 1974).…”

“…Communications between the sinuses and the dorsal venous system can critically reduce the pressure into the CC during erection, leading to an erectile dysfunction condition (Ashdown et al 1979). …”