Goats are seasonally polyestrous with estrous cycles every 20 to 21 days from July through January. Few does cycle in March and April. February, May, June, and July are considered transitional months. Tropical breeds of goats may cycle year-round. Goats reach sexual maturity at five to nine months, but it is not recommended to breed them until they have reached 60 percent of their adult weight, or one year of age.
The presence of a buck causes does to come into estrus. Estrus (standing heat) lasts about 24-36 hours and is recognized by tail-shaking, flagging, nervousness, frequent urination, bleating, swollen vulva, and discharge.
With proper nutrition and management, three kid crops every two years are possible. An ideal management scheme would be to breed in February, then again in September. A buck may breed 50 to 200 does in a single breeding season, but it is recommended that three or four bucks be put with 100 does. As mentioned earlier, bucks should be changed often to prevent inbreeding in the flock (at least every two years).
Nutritional requirements during production are varied according to the state of production. Bucks should be placed on an increased plane of nutrition six weeks before breeding so that they can stand the rigors of covering many does. The nutritional requirements of does vary greatly, depending on the stage of production and gestation.
Between weaning and breeding the doe is in a dry period with nutrient requirements at their lowest. A maintenance diet is sufficient as long as weight lost during lactation is recovered before breeding.
Flushing two weeks before the breeding season can increase the kidding percent. Flushing is increasing the nutrition of the animal prior to breeding, which can increase the ovulation and conception rates. This can be done by turning goats on fresh, lush pasture or by feeding grain for the two or three weeks before the breeding season. This is effective with thin does, but does that are in good condition generally do not benefit.
During early gestation (100 days after breeding) nutritional requirements are not critical and maintenance level will suffice. In late gestation (last 50 days), nutrition is critical since 70 percent of fetal growth occurs during this time. Protein and energy requirements increase drastically, often warranting supplemental feeding programs in the third trimester.
The first eight weeks of lactation have the greatest nutritional demand of any time in the production cycle. This period generally coincides with spring growth, but in accelerated kidding programs, the nutritional requirements must be met with supple-mental feeds.
The gestation period varies from 147 to 155 days, the average about 149 days. Does generally deliver two kids averaging four to six pounds each. Labor begins with one to ten hours of uterine contractions followed by rupture of the water bag. Within an hour of the water breaking, the first kid should be delivered, and all of the kids should be delivered within three hours. A shelter should be available to pregnant does in case of bad weather. Dystocia is rare in goats. Most difficulties occur from mal-presentations in which assistance should be provided. The producer should ensure that each kid receives colostrum within two to four hours postpartum.
Horned kids can be easily disbudded at four to ten days. Males to be kept but not for breeding can be castrated at this time or at weaning. At one to three weeks the kids should be given a clostridium-tetanus vaccine if the doe was not vaccinated prior to kid-ding. Kids can be vaccinated between one and two months and receive a booster two weeks later. Most kids are marketed at four to seven months and at live weights of 40 to 60 pounds and therefore are not generally castrated. If kids are to be sold, this occurs around weaning (three to five months). Kids kept after weaning are usually replacement does or for breeding stock.
Producers often replace 20 percent to 25 percent of their breeding does each year. These doelings, selected at weaning, should be chosen with emphasis placed on multiple births, early-born kids, and kids from does that kid more than once per year. Selection of bucks should emphasize growth rate and muscling, while does should emphasize reproductive traits more. Replacement does should weigh at least 50 to 60 pounds before they are bred. If does are run year-round with the bucks, they will often breed at seven to nine months. If these female kids are bred, they should be fed a supplement for proper growth. Does that do not kid by two years of age should be culled.