"Billy" and "nanny" are outmoded terms for adult male and female goats. Deer are the nearest relatives in the hierarchy to goats, and so adult males are bucks, females are does. However, like horses, fathers are sires and mothers are dams. The offspring are kids, a nongender-specific term, like "child." Male kids are bucklings, females are doelings. A neutered male is a wether. There are many breeds of goats. Some of the more readily identifiable are the Nubians, with long, droopy ears, and the La Manchas, whose ears are simply nubs that look like curled up snails. Nigerian dwarfs are little guys with big attitude. Boers are husky goats raised for meat. Saanens are almost always pure white, noted for heavy milk production. Mohairs are raised for their fine, long hair. In some breeds, both males and females will have horns, and in others, only the males. Goats are found world wide and can survive in almost any climate, eating whatever is available. They can free range, but can be kept in a space as small as a city back yard. More goat meat is eaten than beef or pork world wide, but not necessarily in America.
I raise pure-bred Alpines, the goats that Grandfather had in that old book, "Heidi." That is purely by accident, but, as it turns out, a good choice. Nubians and La Manchas are noisy, continually bleating with what I consider a very irritating voice. Alpines are a quiet breed. Both sexes of Alpines have horns, but all my kids are disbudded by ten days old. Any males born to my herd are castrated by banding at two months.
Bucks are ready, willing, and able to breed at a very early age, and that strong (very strong) smell associated with goats is due only to a breeding buck. The females and wethers have no odor. Like a dude getting ready for a date, a buck will spray himself with what he has available (urine) to make himself attractive to the ladies. Since he replenishes his "aftershave" frequently, that odor clings and rubs off on everything he touches. Females come into season every twenty-eight to thirty days, but will accept a male in only a twenty-four hour period, so he has just a small window of time in which to impress the girls. A buck is a single-minded, sex-stupid breeding machine, but there is a tender courtship ritual, and the girls call the shots. A rejected buck is a dejected buck, but he lives on hope!