Why is it difficult for sows to breed in summer?

Many farmers have found that the conception rate of sows is low in summer, which affects the efficiency of production. In order to solve this problem, we must first understand its root causes. Generally speaking, there are four main reasons. The main results are as follows: 1. the vitality of boar semen is negatively correlated with the ambient temperature in a certain range. The higher the ambient temperature, the lower the semen vitality. In summer, the libido of boars decreased, the semen was thin, the weak semen increased, and the vitality decreased obviously, which was the most direct reason for the low conception rate of sows in summer. Second, the first nutritional reason is that the summer temperature is high, it is difficult for sows to dissipate heat, and the feed intake is reduced. Sows need insufficient nutrients for reproduction, resulting in irregular estrus and ovulation, affecting mating and conception, stillbirth and weak fetus. Second, the stability of vitamins in feed is poor in high temperature season, which leads to the lack or deficiency of vitamins in feed. This is one of the basic reasons for low conception rate and abnormal embryonic development. Third, the lack of green feed or insufficient, resulting in boar and sow constipation. Third, lack of exercise, hot climate, less exercise in sows, lack of hindlimb weakness affects breeding; boars exercise too little, semen vitality decreases, which directly affects the conception rate. Let sows and boars move in the playground for about an hour at a fixed time every day. Fourth, the first cause of the disease is parvovirus disease: infected sows may be in estrus again, or may not give birth to estrus or give birth to only a few babies, or give birth to mummified fetuses. The second is atypical classical swine fever: the immunity of pigs decreases, sows infected with classical swine fever virus often cause reproductive disorders, embryo death and absorption, few litters or relapse in sows. Third, Japanese encephalitis: multiple in summer. The main manifestations of boars are orchitis, sexual function decline, semen quality decline; after the occurrence of Japanese encephalitis in sows, it is difficult to mate, abortion, stillbirth and so on. Fourth, leptospirosis: the disease can cause fetal death, abortion and reduce the survival rate of piglets. Fifth, uterine infection: the most common are Escherichia coli and white staphylococci. Uterine bacteria are brought in by boars during breeding (prepuce effusion, semen itself) and may also come from the vagina. Carrying bacteria in uterus is the most harmful to newly mating sows. Sixth, porcine reproductive and respiratory disorder syndrome (blue ear disease): sows show emaciation, double ears, blue abdomen and breasts, miscarriage, premature delivery, stillbirth and weak babies. There is no milk in sows after delivery, and the highest mortality rate of piglets can reach 100%. Seventh, toxoplasmosis: pregnant sows with toxoplasmosis will have abortion, stillbirth and mummified fetus. Eighth, porcine eperythrozoonosis: late pregnancy and postpartum sows develop mastitis, some sows miscarry or give birth to stillbirths. Fifth, after taking measures to understand the main reasons for the low conception rate of sows, farmers should take targeted measures from the following six aspects to improve the breeding work of sows. 1. Do a good job of heat prevention and cooling: install ventilation or spray cooling equipment. The temperature of pig house should be controlled below 25 ℃ in summer. 2. Appropriate supplement of green feed: each breeder is supplied with 2-3 kg of green feed per day, and multi-dimensional compound electrolysis is added to drinking water to supplement vitamin deficiency. 3. Adjust the diet of breeding pigs: improve the level of feed protein. The feed protein of breeding boars was controlled at 14%. The feed protein of empty sows was controlled at 12.1%. At the same time, increase the supply of vitamins, especially fat-soluble vitamins A, D and E. 4. Rational use of breeding animals: first, to control the breeding frequency. Breeding boars are bred no more than 5 times a week in summer, and artificial insemination is mostly used. The second is to adjust the mating time to adjust the morning and evening mating in summer to evening mating. 5. Do a good job of vaccination: formulate a reasonable immunization procedure according to the occurrence of diseases in the farm. In addition to routine immunity to breeder animals, Japanese encephalitis vaccine should also be injected every spring. 6. Do a good job in sow health care, especially in perinatal health care. Broad-spectrum antibiotics were added to sow feed 1 week before and 1 week after parturition to purify sow disease. Pay attention to the postpartum injection of sows, that is, the use of long-acting oxytetracycline or "streptomycin + penicillin" intramuscular injection within 6 hours after delivery to prevent and cure uterine inflammation.