Prepuce of Male Animals

The prepuce of animals, also known as the sheath, is a tubular fold of skin that covers the cranial free portion of the penis in its non-erect state. It is a secondary andrological organ, composed of a cutaneous fold that envelops the penis.

The prepuce is a double invagination of skin that encloses and protects the free portion of the penis when it is not erect. During erection, it covers the body of the penis behind the glans.

The preputial orifice is the external opening of the prepuce, while the preputial lining is a freely movable membrane or modified skin that is firmly attached only at the glans penis and the preputial orifice.

Blood and Nerve Supply

The blood supply of the prepuce is provided by the external pudendal artery, while the nerve supply comes from the pudendal, iliohypogastric, and ilioinguinal nerves.

Functions

The salient functions of the prepuce of male animals are:

• To enclose the non-erect penis within the preputial cavity.
• To protect the non-erect penis from adverse conditions (e.g., extreme cold, heat, or injury).
• To hold the penis external to the animal’s body.
• To facilitate penile movement by providing an adequate passage through the opening of the preputial sphincter.

Species Variations of Prepuce

Bull

The preputial cavity in bulls is 35 to 40 cm long, narrow, and consists of external and internal layers. The external layer extends from the scrotum to about the umbilicus. It is continuous with the skin at the preputial orifice and is loosely attached to surrounding structures by a large amount of connective tissue.

The internal or penile layer extends to the tip of the glans. It is loosely attached to the body of the penis and closely attached to the glans. The free surface contains several longitudinal folds. Both layers are hairless and composed of modified skin.

Although the cavity of the prepuce is relatively small, it is capable of considerable dilation. The glans is located in the caudal half of the cavity. The preputial orifice, about 5 cm behind the umbilicus, measures approximately 2.5 cm in diameter. It is capable of dilation, faces downward and slightly forward, and is concealed by numerous long hairs.

Ram and Buck

The prepuce is relatively short in rams and bucks.

Stallion

The prepuce of the stallion is shorter but wider. The orifice has no hairs around it. The prepuce is a double invagination of the skin, which encloses and covers the free or prescrotal part of the penis and consists of two layers—external and internal.

The external layer of the sheath extends from the scrotum towards the umbilicus, where it is reflected dorsally and backward to form the margin of the preputial orifice. Dorsally, it is continuous with the integument of the abdominal wall and is marked by a median raphe, the raphe preputii.

The internal layer passes backward from the preputial orifice for a distance of about 15 to 20 cm, and then reflects forward until it approaches the orifice again, after which it is once more reflected backward. This creates a secondary tubular invagination within the cavity of the sheath, known as the prepuce proper. Its orifice is bordered by a thickened margin called the preputial ring.

Boar

The preputial cavity is very long and partially divided by a circular fold into a caudal narrow part and a much wider cranial part. In the dorsal wall of the wider part, there is a circular opening that leads to a cul-de-sac, known as the preputial diverticulum.

Dog

The prepuce of the dog is similar to that of the bull.

Rabbit

The prepuce is well-developed in rabbits.

Cock

The prepuce is absent in dogs.