First off, does should be at least 11-12 months before breeding and in good condition. Fainting does mature slower so if you breed too young, you can run into a LOT of problems! Save yourself possible headache and heartache and wait until they are older. Just like a human child, just because she can get pregnant, doesn't mean she SHOULD get pregnant! Ideally, wait until they are 16-18 months so they kid at just 2 years or a little over.

A doe in heat will indicate her breeding interest by wagging her tail rapidly for the buck ("flagging"). Her urine contains pheromones which tell the buck that she is ready to breed.
A doe's heat cycle is approximately every 18-21 days. Does can be breed at two months but do not allow this, you will end up with problems and most likely death from a doe kidding when she is only seven months old! Wait until the doe is at least 11-12 months and is healthy and in good weight, not too skinny and not to fat (both will cause problems breeding, pregnancy, and kidding).

Signs of heat: (A doe may exhibit any, all, or none of these signs)
* "Flagging" (wagging) her tail.
* Mounting other does.
* Letting other does mount her.
* Fighting
* Letting herself get beat up without defending herself.
* Having a "crush" on another doe.
* No interest in feed.
* Swollen and/or pink rear end.
* Mucous discharge from her vagina
* Tail hair is wet and/or clumped together.
* Baaing for no reason.

A doe's heat lasts anywhere from 6 hours to 3
days depending on the doe.

Bucks will urinate upon their faces, beards, and front legs. When put with a doe in heat, they will put their nose into her urine if she urinates. Raising his head high and turning it from side to side, the buck will curl his upper lip to detect the pheromones which tell him that the doe is receptive to being bred. Bucks have their own special way of getting the ladies in the mood. Along with their smell and peeing habits they also have some certain behaviors that may seem odd, especially if you have never seen it before. These mannerisms are most often exhibited toward the doe in heat, but because breeding and dominance can be so closely related, you will also see does and wethers, as well as bucks asserting their dominance over each other (or you) by exhibiting these traits. Also, does in heat will exhibit these traits and this is called "acting bucky".

These mannerisms are totally normal and the buck may try them on you as well as a doe. When a buck is "in the mood" he doesn't always care what sex or species he tries to breed. If a buck exhibits these traits at you, he may have a crush on you and you should be careful that he doesn't try to mount you when you aren't looking.
* Tongue flapping- The buck will lower his head and flap his tongue at the side of the doe (or you).
* Leg pawing - The buck paws at the side of the doe with a straightened leg. This is usually done at the same time as tongue flapping.
* Blubbering- This is done toward the doe (or you); it can be done in conjunction with leg pawing and tongue flapping.

Does have ascending, cresting, and descending levels of heat-much like cattle. The cresting level is when she is most receptive to conception. This mating ritual described above continues for as long as a day and one-half. The doe must be in a standing heat before successful breeding occurs. Until then, she will run from him, all the while flagging her tail. Sometimes the doe will make sounds similar to those of the buck. During standing heat, some does cry out as if in pain. When successful breeding occurs, the buck will throw his head back as he ejaculates his semen, fainting bucks often faint and fall off sideways. Does may hunch up their backs or squat as if urinating but don't. The sight of goats breeding actually brings other does into heat. Nighttime breeding is common because the nights are cooler. Breeding takes a lot out of bucks, so it is important to keep them in good shape. Write down when the doe was bred so you know when she is due. If she doesn't come back into heat in 18-21 days, there is a good chance she is bred. Sometimes a doe will have a weak or silent heat and not breed, if she has several of these in a row, give her 1/2cc of GnRH (your vet can give it to you) and that should make her heat cycles normal. 

My vet can ultrasound does between 45-70 days bred and let me know sure if they are or not for $4 a goat.

If you have have a doe bred too young, on the 7th day after seeing the breeding, you can give 2cc of Lutalyze. You can also get this from the vet. This WILL cause abortion so do not give it unless you want the doe to abort.

Gestation Period:
The gestation period is the time from conception to kidding. Normally this is roughly 145-155 days, or 5 months. It is best to make sure no kids are nursing on the doe for at least 2 months before kidding (you may need to remove kids, some does will naturally wean their kids).