Fertility and Sterility in the Buck Carol Raczykowski Reviewed by Dr. William Holleman Sterility in the buck is usually the exception rather than the norm and is usually temporary. Male fertility is affected by such things as age, maturity, nutritional status, general health, endocrine balance and normality of sex organs. Sperm quality, nutrition, body weight, maturity, stress, disease, mating frequency, seasonal and climatic changes, and management also play roles in male fertility. With so many things affecting fertility, it's a wonder that sterility is rarely a problem. A buck kid starts mounting behavior as early as one day old. Puberty, the age at which spermatozoa is present in the ejaculate, can vary depending on breed, age and nutrition. Pygmy bucks are capable of breeding as early as 8-12 weeks of age, and they are one of the most outwardly sexually aggressive animals I've treated. From the time of birth the male body begins to changing to prepare them for this experience. A buck is born with his urethral process and glans penis adhered to the inside of his sheath (prepuce) by the frenulum membrane. This adhesion makes it impossible for the buck to copulate until testosterone (a steroid) and practice mounting frees penis from the prepuce. He will then be able to fully extend his penis and copulate. As this takes place, the buck kid will start urinating on front legs and beard and develop a strong odor. Part of his odor is due to the urine, but mostly it is a result of the influence of testosterone on the scent glands located near his horns. This behavior and odor make the buck more attractive to females and stimulates their estrus and receptivity. The blubbering noise and behavior is one of the buck's comical displays. In the early 1990s, someone won $10,000 on the television program, America's Funniest
Home Videos showing this behavior. To a buck, this is serious business. He may paw the ground, wet on his chest and forelegs and exhibit mounting and thrusting behavior. He may nudge the doe and lick her genitalia and smell her urine. This precedes another comical action called flehmen in which the buck raises his head and curls his upper lip in odor detection mode; it looks like he is smiling. All of this usually occurs very quickly with a cooperative doe, and a successful breeding occurs when the buck mounts and ejaculates. Ejaculation is best confirmed by the buck's head jerking back immediately before he dismounts. The doe may react by moving her hindquarters forward, and a drippy discharge can usually be seen coming from her vulva. To increase the volume of semen and concentration and number of the sperm, you can put the buck on a lead and allow him to make a few false mounts on the doe before he ejaculates. This may not work with all bucks, but it is sometimes done with great success in semen collection. If the buck fails to ejaculate, one of the first things to check for is a condition known as a persistent frenulum. This membrane usually detaches as a buck matures but rarely it does not. To examine a buck for this, he is set on his rump and the sigmoid flexure is pressed from behind to manually extrude his penis. If you are not sure how to do this or what to look for, your veterinarian can help. Simple corrective surgery can fix the problem. If the buck fails to impregnate does, it's time to investigate with a breeding soundness examination. This is also a good time to check for the presence of extra teats and other hereditary defects, such as hernias and jaw malformations. A buck with any faulty traits or who is hormonally unbalanced should not be used. The first thing to look for in the physical examination is general health. Does the buck look healthy, including a shiny hair coat, clear eyes and nose? Feet, joints and
16 - The Boer Goat
OAP
