There are many factors that lead to oestrus in sows, besides age, breed and abnormal physiological and anatomical structure, it is also related to contact with boars, delivery, season, nutrition, management, cysts, pseudopregnancy, pregnancy and other factors. At the same time, some infectious diseases will also have these symptoms. To solve these problems, we must analyze the specific problems.

1. People with congenital reproductive organ dysplasia or abnormal pigs should be eliminated in time.

2. For the undernourished, protein, vitamins, minerals and other nutrients in the diet should be increased, and exercise should be strengthened.

3. Obese sows should lose weight, reduce feed or increase roughage, and feed more green feed. Adding 3% calcium chloride to the diet for several days can lose weight.

4. Inject the sow with 500- 1000 units of chorionic gonadotropin or 200- 1000 units of pregnant horse serum. Lure with wild boar. You can also use synthetic PG600, and the effect will be better. It is best not to use triple hormones, estrogen and the like, because such hormones can not increase the number of ovulation even if they help sow estrus performance, and are also unfavorable to sow farrowing.

5. Understand the immune status and infection status of some major infectious diseases in the farm, such as PR, PPV, JBE, PRRS, chlamydia, etc., and make a preliminary diagnosis according to the symptoms of other pigs, strengthen immunity according to specific conditions, replace vaccines, introduce and adapt as soon as possible, ensure the immune status of sows, and adapt to the disease environmental conditions of the pig farm.

6. Ensure that the sow in estrus is in contact with the boar every day 15 minutes, and change the boar frequently.

7. Every day, the sow in estrus has at least 4 hours of sunshine or artificial lighting for 16- 18 hours.

8. Adjust the diet formula to make the contents of vitamins A, D, E, Ca, P and Se in the diet sufficient, and adjust the weight of sows to 3-4.

9. Check whether there is too much zearalenone in the feed to avoid false pregnancy. Replace the qualified feed.

10. Check the situation carefully, especially those sows with quiet estrus, and pay attention to whether the reserve pigs are pregnant.

1 1. Use PG600 and PGF2α to promote estrus. After using PG 600 for 96 hours, you can mate forcibly without estrus (this hybridization is possible, artificial fertilization has never been tried).

12. Eliminate sows with abnormal or oversized physiological structures.