Most goats cycle at 18- to 21-day intervals, but dairy goats and Angoras in temperate regions are seasonal breeders and come into heat in the fall in response to decreasing day length. Pygmies and some individuals of other breeds (particularly Nubians) can cycle at other times of the year. Heat detection is based on behavioral signs, bleating, flagging of the tail, reddened vulva, vaginal discharge (which causes the tail hairs to stick together), and occasional “riding” by other does, although this last sign is far less common than in cattle. Shorter cycles can be seen at the onset of the breeding season and sometimes can be provoked by prostaglandin induction of estrus. Longer cycles are seen later in the season. Goats can show overt signs of estrus while pregnant; natural service will not interfere with pregnancy, but these does should not be artificially inseminated. Most dairy goat females can be bred at 70 lb (32 kg) or 7 mo, if they are born early in the year. Late-born kids may not cycle in the first season. Angora kids frequently are not bred until they are 1½–2½ yr old. Puberty in well-grown bucks can be seen as early as 4 mo.
Last full review/revision July 2011 by Joan S. Bowen, DVM