The reason of boar semen thinning is complicated, so we should grasp the main contradiction and take corresponding measures to solve the problem: a) choose good quality boar feed. The feed consumption of boars is generally small, and the value of boars is high. Therefore, high-grade and high-quality boars premix should be selected to ensure the nutritional balance of boars and obtain high-quality semen. B) boars should be specially protected from mildew. The boar feed is specially added with mildew inhibitors and mildew inhibitors, and the raw materials should be the best. Premix should be bought in small packages (only 200 kg per package of feed), and the storage time should not exceed 7 days, and the storage place should be absolutely moisture-proof. Once the feed is found to be slightly mildewed, stop using it immediately. C) boars need to be restricted. When boars grow to 100_ weight (about 6 months old), they will switch to boars' feed for 2_/ day and lose 0.3 _/day according to their physical condition, so as to keep boars in moderate physical condition. For overweight boars, immediately reduce feed 1/4 and add cod liver oil to the mixture, and drive them to do compulsory exercise when the weather is cool, so as to achieve the effect of losing weight as soon as possible.

Avoid the heat stress of boars. Pig farmers should pay close attention to the weather changes. When the room temperature exceeds 25℃, ventilation should be strengthened. When the room temperature exceeds 30℃, it should be cooled by spraying or spraying. When the temperature continues to reach above 35℃, besides prolonging the cooling time, anti-stress drugs (high stability VC 500g/ ton or baking soda 1500g/ ton) should be added to the boar feed. Pay attention to strengthen ventilation when cooling to prevent high temperature and high humidity. The cooling time depends on the ambient temperature and the degree of hot breathing of boars. E) Use boars in a planned way. Don't use boars too often. Production boars should use at least 1 time every 1 day, and reserve boars should use it for at least 3 days. If the mating task is tight, try to postpone the weaning time of sows or postpone the mating of reserve sows 1 estrus. In addition, for naturally mated boars, semen can be collected, subpackaged and inseminated, and now it is also used without dilution. 1 boar can provide semen for at least 2 ~ 3 sows. E) Adultery boars should be corrected in time. Adultery boars are full of energy and sexual desire, which can usually be corrected by comprehensive measures: a. Adding 20% bran into the feed, reducing the nutritional concentration and removing excess bran until adultery is corrected; B, adjusting boars away from sows to reduce the temptation of oestrus smell of sows; C. Often drive boars to exercise and release excess energy; D. Breeding work is carried out as usual, and the frequency of use is fixed, so it is best to use it for compounding. Only after ejaculation is completed can you leave the breeding bar; E. After self-immorality is improved, it will take at least 1 month to resume normal feeding management. F) Diseases need to be prevented in time. Immunization of Japanese encephalitis vaccine must be carried out before the large number of mosquitoes flood, in February in South China and in March in other areas, and the immunization dose is 2 doses/head (the vaccine is at Fengxian Veterinary Station in Shanghai). Vaccines such as blue ear vaccine and chlamydia vaccine are regularly inoculated in March and September every year. For the existing problems, in addition to supplementary vaccination, anti-inflammatory treatment should be carried out, and such boars should be stopped immediately to prevent the spread of the epidemic. If the quality of semen does not recover within 2 months, they should be eliminated.