Detailed Explanation of Key Technical Points for Gilts Feeding and Management
In pig farming production, sows must be constantly renewed, that is, while culling sows that are slow to come into estrus, old and weak, poor in lactation capacity, and have reproductive disorders, high-quality purebred gilts should be selected in a timely manner to supplement production. So-called gilts refer to female pigs kept for breeding from the stage of piglet rearing to before their first mating. In pig farming practice, selecting gilts is highly technical and runs through their entire growth and development process; a comprehensive examination must be conducted based on the various comprehensive performance traits and manifestations of their parents, littermates, and themselves.
Body condition control and boar stimulation
Gilts should be allowed to fully develop before 60 kg, and from 60 kg to half a month before mating, feeding should be appropriately restricted to prevent them from becoming too fat, with about 2 kg of feed per day, fed twice daily. Gilts can be fed growing-finishing pig feed.
When gilts reach 160 days of age, it is best to drive the gilts into the pen of an adult boar every day for 35 minutes of contact. The pheromones secreted by the submandibular glands of adult boars help induce estrus in young gilts.
Short-term flushing
During the 14 days before mating, gilts can be fed more intensively with free access to feed, so that the gilt can ovulate about 2.5 more eggs, which undoubtedly plays an important role in increasing the litter size of first-litter sows.
Mating gilts at the second estrus at least
The ovulation number of gilts is related to the number of estrous cycles. Mating at first estrus results in a low litter size due to the low number of ovulations. Since first-litter sows account for about 30% of the total sow herd, their farrowing performance directly has a major impact on the whole herd. An important purpose of boar stimulation to make them come into estrus earlier is also to allow them to have several more estrous cycles before mating. Some pig farms keep no records of the number of estrous cycles of the gilts they mate, which is undoubtedly an incorrect operational practice.
Single mating, repeat mating, and double mating
The optimal time for mating should be 10-26 hours after the estrous sow allows the boar to mount. Single mating refers to mating only once with a boar during the sow's estrus. Although this can reduce the number of boars kept, because the optimal mating time for sows is difficult to determine, single mating may reduce the conception rate and decrease litter size.
Repeat mating refers to using the same boar to mate once, then mating again at an interval of 8-12 hours within one estrous period. In production practice, two boars of the same breed are also commonly used to mate twice at intervals. This method can ensure that sperm with relatively strong vitality are often present in the sow's reproductive tract, increasing the chance of egg fertilization, thereby increasing the sow's litter size.
Double mating refers to using 2 boars of the same breed or different breeds to mate with the same sow twice within a relatively short interval (10-15 minutes) during one estrous period. This method can promote accelerated egg maturation, shorten ovulation time, and increase the number of ovulations. However, because the interval between the two matings is short, this method often has disadvantages similar to single mating.
Regarding mastery of the optimal mating time, there are four proverbs for reference: “When the vulva is stained with grass, insemination is just right; when the expression is dazed, insemination will lead to conception; when standing still, it is exactly the right time to mate; when the mucus becomes thick, it is precisely the right moment”.