1. Fast growing broilers and high-yield layers are prone to heat stress. This is because these production animals need high food intake. Food intake, digestion, absorption and metabolism will inevitably generate heat in the body. When the temperature is very high, this can lead to heat stress.
2. Experiments and production experience show that short-term and mild temperature changes (26-32 degrees) can be adjusted and adapted to poultry through slight stress behavior. On the contrary, long-term and large-scale temperature rise (more than 32 degrees) will make poultry physiological function disorder and growth retardation, which will lead to the decline of a series of production indicators (such as growth rate, carcass quality, fertilization rate of breeding eggs, hatching rate, etc.), and even cause poultry failure and death, making producers unprofitable or loss.
3. The mechanism of heat stress harm to the home. The ambient temperature exceeds the appropriate temperature value of poultry. When it exceeds 32 degrees, poultry will show a series of serious physiological and behavioral stress, including hot wheezing, accelerated heart rate, redistribution of circulating blood, intensification of oxidation process in the body, increased excretion of feces and urine, abnormal concentration of sodium, protein and adrenocortical hormone in plasma, especially increased secretion of corticosterone, increased or inhibited neuroexcitability, etc. When these physiological changes are too dramatic, they will cause the following hazards and even death to poultry.
1. Reduce the ambient temperature:
Measures taken recently to reduce the ambient temperature:
(1) indoor spray: spray system for water in poultry houses, especially automatic spray system, regular spray. The key to this method is to master the size and uniformity of droplets. The droplet size should be easy to evaporate and not easy to fall to the ground. Spray should also be sometimes hot and sometimes cold.
The advantages of this method are: low noise, humidity regulation can be considered at the same time, and disinfection of poultry can be considered.
(2) Water curtain or water wall and ventilation: the hemp net is hoisted on both sides of the poultry house, or the net wall is set at one end of the fence house, which is equipped with self flowing ventilator to pre cool the hot air entering the house.
(3) Thermal insulation: the roof of the fence house shall be made of ceramic tile structure, or the roof of iron sheet and nylon sheet shall be paved with fir sheet, and the roof sprinkler system shall be set at the same time. In the hot season, the canopy is often kept wet.
(4) Change the flat feeding to the trellis feeding, and pay attention to the ventilation at the bottom of the shed.
(5) Reduce the feeding density in hot summer season as much as possible.
(6) Increase the shade of the playground.
(7) Grass covers are widely planted in the open space of the poultry farm, and the grassland is often kept moist.
2. Reduce heat production of poultry body and increase heat dissipation:
(1) Change the feeding time and change the feeding from daytime to evening or early morning. Because eating activities, especially the activities of the digestive system, will produce a large amount of body heat, and poultry will rest quietly in the following daytime after full eating in the morning, reducing activity heat production.
(2) During the day, try to reduce the light of the fence as much as possible, because too strong light can stimulate the body's lower thalamic body temperature center to produce heat radiation.
(3) Promote drinking cool water and diuresis, and take away body heat and urine heat with drinking water. If an appropriate amount of NaCl or KCl is added to the drinking water, the amount of drinking water can be increased and the cooling effect can be strengthened.
(4) Adjust the energy source in the beverage, increase fat and reduce carbohydrate content, because the calorific value of fat production capacity is lower than that of carbohydrate production capacity.