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MODULE #: 3B�MALE REPRODUCTIVE SYSTEM

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Testes

Kidneys

The male reproductive organs are located inside the rooster, along the back. This makes it very difficult to castrate a male chicken. Surgery is necessary. This results in the production of a capon – which is a castrated male chicken. This has to be done when the chickens are very young. Surgery involves coming in the from either side of the back to remove the testes. It has to be when the testes are small and the kidneys are not damaged.

The gonads are the sex organs where sperm and ovum are produced. In the male, the gonads are referred to as the testes. In most mammals, including humans, the testes are located in the scrotum which is outside the body cavity. However, in birds, the testes are found within the abdominal cavity. They are located on either side of the backbone and adjacent to the cranial poles of the left and right kidney.

The accessory organs of the prostrate, seminal vesicle, bulbuourethral gland are common in mammals but are not present in birds.

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Testes

Sperm produced in the seminiferous tubules

Ductus deferens

Sperm mature and are transported to the outside of the chicken

Sperm is produced in the seminiferous tubules of the testes. These sperm are then transported by the vas deferens to the outside of the rooster.

Microscopically, the testis (singular form of Testes) consist almost entirely of tubular structures known as seminiferous tubules. There sperm are produced here.

The testes also produce testosterone which is responsible for the secondary sex characteristics of larger comb and wattles and different plumage patterns. Testosterone also helps maintain spermatogenesis (production of sperm) once it has been established by the influence of the pituitary gland.

In mammals, increasing the temperature of the testis can stop sperm production. This is the reason the testicles are located in the scrotum outside of the body cavity. The scrotum is also well supplied with sweat glands and the testes have a specialized arrangement of blood vessels which help to keep the testes cool.

But the testes of chickens are located inside the body cavity, and the body temperature of chickens is higher than humans – about 107F. If temperature effects sperm production, it is at a much higher temperature than that for mammals.

In birds, the ductus deferens is the major storage organ for sperm on each side of the abdomen. It is a very extensive, convoluted tube which runs close to the ureter.

In the pelvis the tube ends in the cloaca at the erectile papilla which is the duct through which sperm is released into the urodeum, which is the mid-region of the cloaca. The ejaculatory apparatus is referred to as erectile papilla and they project into the urodeum.

Sperm undergo maturation in the ductus deferens.

The phallus is analogous to the mammalian penis. There are two main varieties of phallus’ in male birds. The truly intermittent organ (alternately functioning and not functioning or alternately functioning properly and improperly) is seen in ratites like the ostrich, and in some waterfowl. The waterfowl need it so that the sperm is not washed away in the water. Presumably ostriches need it because of their large size. Domestic fowl have a non-intromittent type. The ‘phallus’ is located on the ventral lip of the vent.

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Testes

Ductus deferens

Cloaca

Vent

Digestive

system

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