How to manage cotton after topping in July

Heat or high temperature and humidity is one of the most harmful factors in the breeding industry, which will lead to the occurrence of heat stress syndrome in livestock and poultry. Heat stress suppresses the immune function of the body, reduces the concentration of immunoglobulin in blood and the number of lymphocytes in blood, resulting in the decrease of phagocytosis of macrophages in the body and infectious diseases of livestock and poultry. Therefore, heat stress will make livestock and poultry prone to all diseases. As the higher the production performance of modern excellent livestock and poultry breeds, the worse the ability to resist heat stress, serious heat stress often causes the livestock and poultry with high performance to die first, resulting in serious economic losses. This paper introduces some measures to improve the internal environment of livestock and poultry for the majority of farmers' reference.

1. Reasonable adjustment of dietary nutrition level

(1) adjusting the content of protein and amino acids: reducing the content of dietary protein, but maintaining the level of essential amino acids can improve the growth rate and survival rate of the body. Broilers can add D-methionine; feeding synthetic lysine instead of natural protein is beneficial to pigs.

(2) improving energy level: the adjustment of energy concentration in diet should be based on the principle of minimizing the production of heat consumption. Fat is a nutrient with the lowest heat consumption. Properly adjust the proportion of essential fatty acids in feed and use fat to replace part of carbohydrates in order to increase the energy concentration of feed and improve the adaptability during heat stress. Generally, fat is added to the diet by 2% and 3%.

(3) Mineral addition: during heat stress, the excretion of potassium, sodium, zinc and molybdenum increased, the excretion of calcium, manganese, selenium and copper in feces also increased, and the storage of magnesium and phosphorus also decreased. When the ambient temperature is higher than 20 ℃, for every 1 ℃ increase, the actual content of calcium, phosphorus, sodium and chlorine in the feed should be 1.5% higher than that required at 20 ℃ in order to meet the needs of the body.

two。 Application of anti-stress additive to alleviate heat stress

(1) Vitamin C and vitamin E supplement: when heat stress occurs, on the one hand, the increase of cortisol secretion increases its demand for vitamin C, and the increase of corticosteroid secretion has an inhibitory effect on the immune function of the body. On the other hand, the ability of livestock and poultry to synthesize vitamin C decreases, so the addition of vitamin C is beneficial to relieve heat stress. Vitamin C can be supplemented by feed or drinking water, supplement: 100g-150g / ton feed for broilers; g feed for pigs. When added through drinking water, add 1 gram per liter of drinking water, and uninterrupted water supply.

Vitamin E also plays a role in anti-heat stress. There are some changes in the cells of the body during heat stress, so the addition of vitamin E can stimulate the immune organs, enhance the immunity of the body, and help to improve the ability of anti-stress. Adding 200-300mg/kg vitamin E to the diet of broilers can significantly increase the concentration of T3 and T4 in the body; the vitamin E in the diet of laying hens is increased from 10IU to 35-50IU, and the laying rate is increased by 1.5% 10IU 5.5%; the addition of 200IU/Kg vitamin E to broiler pigs can effectively alleviate heat stress and has a tendency to improve production performance.

(2) regulating electrolytes and maintaining acid-base balance: many studies have shown that the addition of sodium chloride, potassium chloride and sodium bicarbonate to diet or drinking water is beneficial to restore acid-base balance and improve production performance. Feed is most suitable to add 0.5% sodium bicarbonate.

During heat stress, the respiratory rate increases and the levels of CO2 and HC03- in the blood decrease, which leads to the increase of pH value and respiratory alkalosis. The addition of acidifier to the feed can decrease the elevated pH value in the blood and regulate the acid-base balance, thus avoiding or alleviating the adverse reactions caused by heat stress. The commonly used acidifiers are lactic acid, citric acid and fumaric acid.