Berkshire hogs are bred by natural or artificial insemination methods. Natural breeding requires both a male pig and female pig to be present. Artificial insemination requires only the female be present, properly stored semen and insemination equipment is required; this can be purchased from hog semen collection companies.
The young female pig reaches puberty at five to six months of age. She comes into estrus or heat every 21 days after she reaches puberty. A male is ready to impregnate females between eight to twelve months of age. The most important step to a successful breeding is detecting when the female is in heat and timing the breeding periods.
The primary sign of estrus in the female pig is a swollen, red vulva. Other signs that may be present include the pig standing still when your hands are pressed on her hind quarters, increased urination, restlessness and mucus from the vulva. It's vitally important that estrus be detected when you are using artificial insemination, as if you miss one estrus cycle you will have to wait 21 days for the next cycle. Female pigs should be checked for estrus every 12 hours.
There are two methods of natural breeding: leaving the male in with a pen of female pigs or hand mating. Hand mating is bringing the male each female's pen for mating.
In both natural and artificial breeding it's best to allow breeding to occur twice within a 24 hour period to ensure a successful pregnancy.