With the high temperature and rainfall in summer, chicken easily occur heat stress. The main reason is related to the chicken characteristics and environment. Chickens are thermostatic animals with dense body feathers, no sweat glands on the skin, poor heat dissipation capacity, and poor ventilation in the chicken house, which lead to changes in the metabolism and physiological function of laying hens, reduced feed intake and increased drinking water, thus affecting the laying rate, feed utilization rate, disease resistance and even death. The most suitable temperature for chickens is 15-24°C. When the temperature exceeds 28°C, the chicken body will be up against heat stress.
What's the effect of heat stress heat on laying hens?
1.Reduced feed intake：When the environment temperature decreases, the body temperature is also significantly increased, the feeding intensity increases, the gastric motility declines, the nutritional function and the feed intake decreases. Experimental shows that when the temperature is 15-24°C, the feed intake of the laying hens decreases and increases by 1.6-1.8% with the temperature rises and falls by 1 degree. If the temperature is above 35 °C per week, the feed intake can be reduced by 40-45%.
2.Reduced egg weight: Due to heat stress, the secretion of digestive enzymes is reduced, and the chicken's large amount of drinking water reduces the ability of the layer to digest nutrients, so that the protein and other nutrients in the feed cannot be fully absorbed and utilized, and the egg weight Lighten up. (When the temperature reaches 30°C, the egg weight can be reduced by about 20%).
3. Decrease in egg production rate and eggshell quality: The most suitable temperature for laying hens is 15-24°C, and the best temperature is 18°C. At 25-30 °C, the egg production rate decreases about 1.5% with the ambient temperature rises by 1°C degree. When the temperature is higher than 30°C, the egg production rate will decrease by 10-20%, and the eggshell thickness will decrease by 5-7%. At the same time, the incidence of soft-shell eggs can reach 2.4-16% under heat stress. And the occurrence of broken eggs accounted for 21% of the total output.
How to relieve heat stress and improve production performance?
- Strengthen management and ventilation, reduce the temperature of water, install cooling systems, and prepare stress treatment plans.
- Adjust the feed formula rationally to ensure adequate supply of various nutrients such as energy and protein in the feed.
- In addition, some anti-stress feed additives are added to the feed, such as bile acids:
(1) Adding bile acids can effectively improve the utilization rate of oil, reduce body heat gain, and relieve heat stress.
(2) Adding bile acids to degrade endotoxins, discharge toxins, reduce oxidative stress, and relieve heat stress.
(3) Adding bile acids to increase the activity of liver antioxidant enzymes, reduce MDA content, increase the level of antioxidant TAOC, reduce oxidative stress, reduce endoplasmic reticulum stress, and relieve heat stress.
