How to determine the best time for artificial insemination of sows

Generally, 19—30 hours after the sow comes into estrus, when the swelling and redness of the sow's vulva just begin to subside and stringy mucus flows out, and when the sow stands still when pressure is applied to the rear of her body, insemination can be carried out. Before insemination, first check whether the sow's vaginal secretions are normal. If normal, once standing occurs, insemination should be performed, and then again every 8-12 hours until the sow no longer accepts pressure on her back.

1. What to do if a sow does not come into estrus?

1. Massage the udder: after feeding every morning, let the sow lie on her side, and use the palm of the hand to perform superficial massage on each udder for 10 minutes. After signs of estrus appear, perform superficial and deep massage of the udder for 5 minutes each. On the day of insemination, perform deep massage for about 10 minutes.

2. Driving exercise: driving the sow to move can promote metabolism, improve body condition, and encourage the sow to come into estrus and ovulate; or clamp the sow with both legs and pat her buttocks with the hand, which can appropriately promote estrus in the sow.

3. Grouping and pen merging: merge sows that are not in estrus into the pen of sows that are in estrus. Due to the change in environment and stimulation such as mounting, sows that are not in estrus can enter the state as quickly as possible.

4. Hormone-induced estrus: inject the sow intramuscularly with 100 units of human chorionic gonadotropin, or subcutaneously inject 5 milliliters of human pregnant mare serum, which has the effect of promoting estrus and ovulation in sows.

5. Semen-induced estrus: take 20 milliliters of boar semen, slowly infuse the semen into the sow's uterus with an insemination catheter, and keep rotating and moving the insemination catheter back and forth, while sprinkling a small amount of semen on the sow's snout, which can promote estrus in the sow.

2. How to determine whether a sow is pregnant?

1. Look at the udder: 3-4 days after insemination, gently pinch the sow's second-to-last pair of teats with the hand. If a relatively hard milk duct is found, it indicates that she has conceived; 30 days after insemination, the attachment site of the sow's teats shows a dark purple halo and begins to elongate, indicating that she has conceived; observing the arrangement of the teats from between the two hind legs behind the sow, if the front ends of the teats open outward and the base of the teats swells and bulges, it indicates that she has conceived.

2. Look at behavior: after insemination, the sow shows lethargy and greediness for food, a gentle temperament, rapid recovery of body condition, glossy hair and skin close to the body, gradually increasing abdominal circumference, a dry vulva contracted into a line, and a drooping tail; or the lower commissure of the vulva gradually contracts and closes tightly and clearly tilts upward, indicating that she is already pregnant.

3. Look at the estrous cycle: if it is a sow with a normal estrous cycle, after estrus and insemination, if she no longer comes into estrus after one estrous cycle (18-25 days), it can be preliminarily judged that she is already pregnant.

4. Test the urine: take 10 milliliters of morning urine from a sow 5-10 days after insemination, add 1 milliliter of 5% iodine tincture or 1 milliliter of vinegar, and heat to the boiling point. If the urine turns red, it can be judged that the sow is already pregnant.