Summer temperatures are high, high temperature and heat prevention have become the focus of pig factories, especially in the south of the Yangtze River, the summer temperature above 30 ° C -35 ° C for up to 5-7 months. However, except for the piglets, the suitable temperature of all other types of pigs is below 24 ° C, and the continuous hot weather far exceeds the suitable temperature of the pig herd.

Hazards of high temperatures to pig farms:

High temperature caused by heat stress reaction to the amount of food damage: during the heat stress reaction, part of the excitement of the feeding management center is suppressed, while the digestive system is improved, the drinking water is improved, in order to accelerate heat exhaust, reduce heat accumulation, so that the amount of eating material is further reduced. Reducing the amount of food eaten is a defensive reflection of the small animals in maintaining the balance of human body heat in a high temperature natural environment. The amount of food eaten decreased by 1.6% per 1°C increase in the 21°C-30°C range and 4.6% per 1°C increase in the 30°C-38°C range.

The harm of high temperature to old sows and breeding pigs: when the working temperature is higher than 32-35 ° C, the deep basal body temperature of breeding boars is higher than 40 ° C, and the testicular temperature rises. With the decrease in semen quality, the male sperm count decreases, the charm decreases, and the low quality sperm night will endanger the number of litters of the old sow. After 7-14 days after the high temperature weather stress response, the quality of boar semen decreases, generally after the high temperature stress response 7-8 weeks, the semen night quality can be restored, the high temperature will continue to reduce the sexual desire of the breeding pig, and cause certain harm to the estrus period, mating and pregnancy of the old sow. Old sows often show boredom and resentry during high temperatures, and the estrus cycle increases. 3 weeks before mating, 3 weeks after mating and 3 weeks before delivery of pregnant women, the harm of high temperature to old sows is more serious.

Part of the reduced reproductive capacity of old sows in hot climates is due to lower litter yields and early embryo deaths. In about 1 to 3 weeks before and after mating, the old sow is sensitive to high temperatures, especially in the case of high temperatures, and its littering is significantly reduced, and the early embryo digestion, absorption and death occur, which in turn significantly reduces the number of litters. The end of pregnancy is the key period for the baby's weight increase, high temperature will endanger all the normal growth and development of the fetus, so that the old sow eats less material, the nutrient content is not enough, and then causes the fetal baby to be born to reduce the weight, and the growth retardation after birth. At the end of pregnancy, the human immunoglobulin component in the primary milk and regular milk of the old sow is low, the human immunoglobulin component in the blood night of the piglet is significantly lower than that of the normal piglet at the age of one day of birth, and the human immunoglobulin component in the primary milk and regular milk of the old sow is very critical to the acquired immunity of the piglet, and when its composition is low, it will cause the immunity of the piglet to decline.