Beware of heat stress in pigs in July

In July, Anhui Province entered a hot and scorching heat, and issued a heat prevention warning to the aquaculture industry. With the large-scale intensification of the pig industry, the density of pigs increases, and the breeds of pigs are mainly outside the three, pigs are more prone to heat stress. How to control the summer heat stress of pigs has become one of the important tasks of pig farmers.

Heat stress is an invisible killer.

Compared with the epidemic disease, the damage of heat stress to pig farms is often invisible.

The most suitable temperature range for fattening pigs is 18 Mel 21 ℃, 32 Mel 38 C belongs to the range of heat stress. When the temperature was higher than the optimum temperature of 5 ℃, the feed intake of pigs decreased by 6% Mel 21%, and heat stress decreased the feed intake of pigs.

Under the condition of heat stress, the conception rate of sows decreased, the number of stillbirths at the end of pregnancy increased, litter weight decreased, and even abortion. Sows may also decrease in feed intake, resulting in a decline in the quality and quantity of milk in lactating sows, and ultimately affect the survival rate and weaning weight of piglets.

Heat weakens the mating desire of boars and reduces the quality of semen. High temperature reduced ejaculation and the ratio of live sperm to total sperm in boars. The fertilization rate was 85% 90% at 20 ℃ and 50% 60% after exposure to 33 ℃ for 2 hours. The effect of high temperature on boar semen quality can even last until 3 months later. One of the reasons for the decline in sow regurgitation and litter size in the second half of each year is the high temperature.

Pig raising should be fastidious

First, ventilation and thermal insulation. First of all, pig farms should be built in the open area of ventilation and choose to sit north and face south. Our province should use open or semi-open pig houses that can make use of natural ventilation. Fans or fans can also be installed to promote air flow, effectively reduce air humidity and take away heat in the house. the effect of longitudinal ventilation is better than that of horizontal ventilation. Planting tall trees around pig farms and sheds can reduce sunlight exposure.

Second, spray to cool down. Evaporative cooling is the most effective method. When the house temperature is too high, hose or sprayer can be used to regularly spray water to the pig (except delivery house) and roof or artificially spray water to cool down. For positioning bars and delivery house sows, drip cooling system can be used. For fasting, pregnant sows and growing-finishing pigs, spray or spray can be used to cool down quickly, and the temperature in the house can be reduced by 5 Mel to 8 degrees in 10 minutes. However, spraying water to reduce temperature will increase the humidity in the house, high temperature and humidity will aggravate heat stress, and will also cause the spread of pathogenic microorganisms in the house.

Third, wet curtain fan cooling. The wet curtain fan cooling system was originally used to cool the summer temperature of the chicken house, which can reduce the temperature of the house by 5ml 7C. The drier the air is, the higher the temperature is, and the greater the cooling range of the air passing through the wet curtain is, the more obvious the effect is. At present, wet curtain cooling is more suitable for male and female pig houses, and the cost is also relatively low.

Fourth, air conditioning cooling. Air conditioning cooling can not only reduce the temperature, but also control humidity, but the cost is too high. However, for breeding pig farms and production farms using artificial insemination technology, it is worthwhile to carry out centralized management and install air conditioning on boars, which can significantly improve the semen quality of boars in summer.

Pay attention to your diet in hot weather

Pigs need to pay attention to diet when it is hot. Such as different feed formulations at high temperature, adding a variety of trace elements and minerals, increasing green feed, etc., are simple and effective measures.

First, adjust the feed formula. At high temperature, in order to reduce body heat gain and heat dissipation burden, pigs will inevitably reduce feed intake, resulting in insufficient intake of nutrients such as energy and protein, thus affecting the growth and development of pigs. The necessary adjustment of feed formula is one of the effective measures to overcome heat stress. As the more nutrients heat up, the more heat dissipation burden of pigs, the more serious heat stress, so choose palatable, fresh and high quality raw materials with diet, properly reduce the ratio of high fiber raw materials, and control the level of crude fiber in diet. to reduce the production of body heat.

Fat has the advantages of small volume, high net energy value and less body heating. it is an ideal energy source for pigs under high temperature conditions, and less than 5% oil can be added to the feed. The demand for protein of pigs increases under heat stress, so increasing the content of crude protein in feed can improve the feed utilization rate and reduce the heat dissipation burden of pigs in high temperature season. Adding 200 Mel 500 mg / kg vitamin C and 200 mg / kg vitamin E to the feed can enhance the ability of anti-heat stress, increase feed intake and daily gain. Proper addition of sodium bicarbonate (250 mg / kg) and trace element potassium can also alleviate the adverse effects of heat stress on pigs. Adding appropriate amount of green feed to boars and sows can improve the appetite and anti-stress ability of pigs.

Second, strengthen management. Reducing the feeding density can reduce the temperature in the pigsty. Ensuring water supply, changing dry feeding to wet feeding or using pellet feed can increase pig feed intake. Adjust the feeding time, increase the feeding times, feed in advance in the morning, postpone the feeding in the afternoon, avoid hot feeding, and feed once at night. Avoid high temperature time and even seasonal breeding.

Third, add anti-heat stress drugs. When the temperature exceeds 34 ℃, anti-heat stress drugs such as vitamin C, vitamin E, biotin and choline can be used as appropriate, and 10mg / kg daidzein or 400mg / kg taurine can also reduce the effect of heat stress on fattening pigs. Supplementation of 300 μ g / kg chromium (chromium picolinate) in pig feed can alleviate high temperature stress, increase feed intake and daily gain, and reduce feed-to-gain ratio. It will take some time for chromium to play a role (2 weeks later). Some Chinese herbal medicines can coordinate the physiological metabolism of pigs under high temperature, promote the growth and development of pigs, and improve the immune function of pigs. Feed additives such as Hawthorn, Atractylodes, tangerine peel, betel nut, Scutellaria baicalensis and Daqu, which have the functions of appetizer and spleen, clearing heat and relieving heat, are selected to prepare feed additives, which can alleviate the effect of high temperature on pigs and improve weight gain and feed utilization rate.

Chinese herbal medicine, vitamins, minerals and electrolytes are mixed into additives according to a certain proportion, which can coordinate the regulatory function of pigs, enhance their adaptability and resistance to high temperature, and thus alleviate the heat stress of pigs.