GENITAL ORGANS OF THE MALE.—The genital organs of the male are the testicles, the ducts or canals leading from the testicles, the seminal vesicles, the glands lying along the urethra, and the penis.
[Illustration: FIG. 17.—Photograph of model of udder of cow: milk duct; milk sinuses; and glandular tissue.]
The testicles are the glandular organs that secrete the spermatozoa, the essential elements of the seminal fluid. These glands are lodged in the scrotal sack, situated between the two thighs.
Lying along the superior border of the testicle is a mass of ducts, the epididymis. The vas deferens is the canal or duct that passes from the epididymis to the region of the bladder and terminates near its neck by emptying into the seminal vesicles.
The seminal vesicles are two membranous pouches situated just above the bladder. They act as receptacles for the seminal fluid. Two short ducts, the ejaculatory, carry the seminal fluid from the seminal vesicles to the urethra.
The prostate gland is situated near the origin of the urethra. Cowper's glands lie along the course of the urethra and near the origin of the penis. These glands empty their secretions into the urethra and dilute the seminal fluid.
The penis is the male organ of copulation. It originates at the arch of the ischium and extends forward between the thighs. It may be divided into fixed and free portions. The free portion is lodged in the prepuce or sheath, but at the time of erection protrudes from it.
STERILITY, IMPOTENCY.—Fecundation does not always follow intercourse of the male and female. Impotency in the male and sterility in the female frequently occur.
The causes are quite varied. A normal copulation may be impossible because of injuries to, and deformities of, the parts and tumor growths. Deformed genital organs and obstructions of the os by growths and scar tissue are causes of sterility in the female.
Failure to breed is commonly caused by faulty methods of feeding and care. Over-feeding and insufficient exercise may result in the body tissues becoming loaded with fat. This may cause a temporary sterility, but if persisted in, as is frequently the case in show animals, the sterility becomes permanent because of the genital glands failing to secrete ova and spermatozoa, or the lack of vitality of the male and female elements. Old age and debility from disease or poor care may induce loss of sexual desire and an absence of, or weakened spermatozoa in, the seminal fluid. The refusal of the male to serve certain females is sometimes noted.