Detailed Explanation of Key Technical Points for Feeding and Management of Weaned Sows
Under normal circumstances, 3 to 10 days after piglets are weaned, the sow can come into estrus and be mated. Some sows even come into estrus before weaning, while others remain in anestrus for a long time or fail to conceive after estrus. The cause must be identified: disease, nutrition, management, etc., so that breeding use can be restored as soon as possible.
1. Early weaning is recommended.
2. For first-parity sows, weaning should not be later than 28 days.
3. Two to 3 days before weaning, the sow's feed should be reduced as appropriate to promote milk let-down cessation; vitamin B6, etc., should be added to reduce the occurrence of mastitis.
4. Feeding and management should be tailored according to breed, parity, body weight and weight loss, with especially notable results for the first two parities.
5. Feed should not be changed on the day of weaning; changing feed on the day of mating is most appropriate. Be careful not to waste feed.
6. Rapid conception. Conceiving within 7 days after weaning is ideal. Increase the daily supplement of vitamin E 200 mg and carotene 400 g until 21 days after mating; this can promote ovulation and increase litter size. An empty sow at about 80% body condition conceives easily and has a high farrowing rate. After the 3rd parity, weight loss in sows basically does not affect estrus.
7. Sows of similar breed, parity and body weight should be weaned at the same time, and group housing of 4 to 6 head is preferable.
8. Accelerate estrus. Use boar stimulation and induction (touch, smell, hearing and visual stimulation are very important for optimizing reproductive performance, but raising sows adjacent to boars is unwise), Chinese and Western veterinary drugs (stir-fried chives plus brown sugar fed to the sow), sex hormones, and udder massage (every day after the morning feeding, massage the surface of both sides of the udder for 10 min; after estrus begins, change to 5 min; on the morning of the mating day, massage deeply for 10 min to promote ovulation). Recommendation: for multiparous sows that do not come into estrus 10 to 15 days after weaning, hormones may be used, and if necessary, inject again after half a month.
9. Those that remain in anestrus for a long time or fail to conceive after repeated mating should be kept under concentrated feeding and management; otherwise, they must be resolutely culled.
10. Pay attention to deworming, once per parity.
11. Do a good job of immunization and vaccination, test antibodies at fixed times and regular intervals, and keep records. 12. Update and cull.
Early weaning can both prevent the vertical transmission of many diseases and increase the number of litters per sow per year, but early-weaned piglets require careful nursing. Getting sows to come into estrus and be mated as soon as possible is the key to increasing the number of litters per year. Weaning the sow while keeping the piglets can be recommended. On the premise of meeting nutritional and health needs, using hormones can shorten the time from weaning to estrus and increase the conception rate. According to research, when sows are exposed to exogenous estrogen or other similar substances 11 to 14 days after estrus, it can cause pseudopregnancy in those that did not conceive, leading to a significant decrease in the number of implanted embryos and thereby causing a low litter size.
After weaning, sows should be housed in the same pen according to similar parity, size and body condition. This not only reduces the vertical transmission of diseases but also prevents weaker sows (thin and weak sows are mostly those with many piglets born, many piglets nursed and good milk production) from being culled too early due to injury or malnutrition. This method is especially effective for the first three parities. In addition, check the udder 2 to 3 times daily and squeeze out residual milk. If the udder is found to be hard and no milk is being produced, first, massage the udder with a warm wet cloth and squeeze out the milk; second, put the original litter of piglets back beside the sow to suckle, so that the udder softens. This can effectively prevent the occurrence of mastitis.