Читать книгу Bovine Reproduction - Группа авторов - Страница 310

The penis of the bull calf cannot be extended prior to puberty due to the interdigitating attachment of the skin of the penis and prepuce and the lack of a sigmoid flexure. During puberty, androgen production shifts from androstenedione to testosterone, and the attachment of the penis and prepuce begins and should be complete between 8 and 11 months of age. Occasionally, young bulls between the age of 12 and 14 months will present with incomplete separation [4, 7]. In these bulls separation can be completed by pulling the prepuce back from the free portion of the penis. These tissues should separate easily and hemorrhage is seldom a problem.

The penile frenulum is a thin band of connective tissue on the ventral midline of the free portion of the penis, which adjoins the prepuce. Normally the frenulum ruptures during penile separation from the prepuce. When the frenulum does not rupture, the penis extends but the frenulum causes ventral bending of the distal penis during extension (Figures 19.7–19.9). Surgical repair is relatively simple. I recommend ligating each end of the frenulum and transecting the tissue to reduce the possibility of hemorrhage, although not all practitioners adhere to this practice (Figures 19.10–19.12). The owner should be advised that this condition is considered to be heritable and retaining the bull's sons as sires is not recommended.

Figure 19.7 Persistent frenulum preventing complete straightening of erect penis.

Figure 19.8 Persistent frenulum with two branches attached from prepuce to penis.

Figure 19.9 Very short persistent frenulum preventing separation of penis and prepuce.

Figure 19.10 Transfixation ligatures on each end of persistent frenulum.

Figure 19.11 Excision of frenulum adjacent to transfixation ligatures.

Figure 19.12 Completed excision of frenulum.