Heat stress disease refers to an adaptive disease that occurs when animals are strongly stimulated by heat stress sources. It mostly occurs in the late spring and early summer, during this season, the climate becomes hot suddenly, or the chicken house with high density and poorly ventilation.
The normal body temperature of the chicken is between 40-41.7℃. When the air temperature is low, it is more comfortable for the chicken. The ideal temperature is 20-25℃. Because the chicken has no sweat glands, when the ambient temperature is too high, it can only rely on the respiratory system to regulate the body temperature.
That is, open mouth to breathe，increase the breathing rate and the exchange of heat with the outside air. Excessive air exchange can cause respiratory alkalosis, loss of appetite, tremors, convulsions, and even coma until death. Deep and shallow pathological breathing can be seen before death.
Manifestations of heat stress
The dead chickens have poor blood coagulation and slow body cold; lung congestion and edema, with purple-black color; diffuse hemorrhage of the pleura around the heart, bleeding in the pericardium and intestinal mucosa, and scattered bleeding spots in the liver.
Sick chickens are mentally wilted, with disheveled feathers, stretch their necks and open their mouths to breathe, increase in water intake, and decrease in feed intake. They have difficulty breathing, and their combs or meat beards are dark purple.
Heat stress hazards
1.Mild heat stress will cause decrease in egg volume, lighter egg weight, and thinner eggshells, while severe heat stress will cause chicken deaths or even large number of deaths.
2.The number of broken and soft-shelled eggs increased, and produces small and thin-shelled eggs, and the quality of the ingredients in the eggs reduced; the growth and development of broiler chicks are slow, and the weight gain is slow; the production of sperm in breeding males is reduced, and the vitality is reduced.
3.Chickens with chronic heat stress for a long time can see some hair loss. The higher the ambient temperature, the less optimistic the chickens.
The prevent and control of heat stress
1. Drinking water management. The water intake of chickens rises sharply in high temperature environment. Increasing the water intake can replenish the water excreted by breathing and urine and prevent the chickens from being dehydrated. Therefore, it is very necessary to provide clean and sufficient cold water. In addition, gasping will change the chicken's electrolyte balance, so add some electrolytes to the water, which is beneficial to the health of the chickens.
2. Adjust the feeding time and frequency. In high temperature environment, the feed intake of chickens will be reduced, resulting in insufficient intake of nutrients, and the nutritionally deficient chickens will gradually become thinner. Therefore, it is necessary to increase the feed intake and nutrient intake of the chickens.
To maintain adequate nutrition, it is necessary to adjust the ratio of feed to make up for the lack of intake at high temperatures. In addition, the feeding time was changed to cooler early morning and evening.
3. Ventilation and cooling equipment. Prepare fans, water curtains, water sprays and other cooling facilities, and do not water the chicken coop to avoid high temperature and high humidity to increase stress. Properly plant trees and grass around the chicken house for shelter. The grass should less and low or it will restrict air flow. Be sure to pay attention to electrical circuits and power failure notifications. It is best to have a generator to avoid heat stress caused deaths of chickens due to emergency power failure.
4. Feeding management. Reduce breeding density, eliminate old, weak, sick, and low-yielding chickens, and avoid overcrowding of chickens. Remove the litter in time to avoid microbial decomposition caused heat generation and maintain environmental sanitation.
5. Reasonable drug prevention. Add the right amount of vitamins, cod liver oil and other nutritional products. Diets generally reduce carbohydrate content and increase fat and other energy additions, which are not conducive to liver health and are prone to liver diseases such as fatty liver.
It is recommended to add bile acid to improve the utilization of feed energy, provide sufficient energy supply, but also reduce the amount of fat added, and avoid fatty liver caused by long-term intake of high-fat feed.
Adding Eucommia ulmoides leaf extract to scavenge free radicals, anti-oxidation and anti-stress, help chickens grow and develop healthily, enhance immunity, and reduce heat stress.
