The Buck
The male goat is called a “buck” or “billy.” If he is castrated, he is called a "wether." When male goats are between 6 to 12 months of age, they are sometimes referred to as “bucklings.” Male goats can weigh anywhere between 27 to 350 pounds, depending on their breed, health and nutritional status. The earliest age the buck should be used for breeding is 1 year of age. The number of does the buck can service during the breeding season is referred to as “Buck Power” (Noble, 2004). Therefore, at 1 year of age, the buck should not be pressed to service more than 10 does at one time. When he is 2 years old, he should be allowed to service 25 does at one time, during the breeding season or per month).
At the age of 3 and older, he can breed up to 40 does at one time, providing his health and nutritional needs have been met. The number of does a buck can service at one time is also dependent upon whether he is managed by a hand- or pasture- mating system and on the terrain. The buck has the greatest genetic impact on the herd and should not be neglected at any time.
Like the doe, day length also has an effect on the reproductive processes in the buck. The bucks have the highest libido, fertility, semen quality and volume in late summer and fall, which is directly correlated to the seasonal breeding pattern of does (Senger 1984; Wildeus, date unknown). As the photoperiod lengthens, sperm production is reduced, and more abnormal spermatozoa (the mature male gamete or sex cell) are present in the ejaculate. During the fall, the endocrine system also increases levels of testosterone and luteinizing hormone (Ritar, 1990).
The Doe
The female goat is called a “doe” or “nanny.” When she is between the age of 6 to 12 months she is sometimes referred to as a “doeling.” The doe can reach puberty between 4 to 12 months of age. However, overfeeding or underfeeding the doe can hinder puberty as well as her reproductive performance. A lack of adequate nutrition will subsequently hinder lactation.The genetic makeup of the animal also determines when puberty occurs in the female. Puberty is reached when the female exhibits her first heat and first ovulation.
Estrus, or heat, is the period in which the doe will stand and allow the buck to breed her. This phase of the reproductive cycle may last between 12 to 36 hours. The period from one heat cycle to the next is referred to as the estrous cycle. In goats, the estrous cycle occurs every 18 to 24 days, or 21 days on average. Does that are in heat may exhibit signs of mucous discharge, swollen vulva, bleating, frequent tail wagging and standing in heat. The doe can be bred when she has reached at least 80 pounds of body weight or 60 percent to 70 percent of the adult weight for her breed. Does that are bred too early may have difficulties during kidding (dystocia), or their future reproduction performance may be impaired.
Following ovulation, the egg is released from the ovary and is directed by the infundibulum, a funnel-like structure, into the oviduct, where fertilization occurs. The egg will remain viable for 12 to 24 hours after ovulation. When the buck ejaculates, the sperm , which are viable for 48 hours after copulation, travels up the vagina to the oviduct to fertilize the egg or eggs. The fertilized ova, or embryo, travels to the uterus, where it attaches to the uterine wall within 15 to 20 days after fertilization for nourishment and removal of waste products throughout the duration of gestation (Wildeus, 2005).
The gestation period of the doe ranges between 145 to 152 days, or 150 days on average, and under normal circumstances, the doe can have multiple births.
