Non-protein nitrogen refers to non-protein nitrogenous substances, commonly used ammonia, urea, ammonium bicarbonate, ammonium hydrogen phosphate and urea complexes, etc., which can replace a part of protein feed, such as fish meal, bean cake (chicken) and so on. The urea complex can slow down the decomposition of urea into ammonia in the rumen, reducing the risk of ammonia poisoning and increasing the nitrogen availability. First, the toxicity and detoxification of urea. Urea itself is non-toxic, but the rate of decomposition and release of ammonia is too fast and can easily lead to poisoning. Symptoms of poisoning usually occur within 0.5 to 1 hour after feeding. Symptoms of mild symptoms include slow motion, severe dyspnea, muscle tremors in the extremities, sweating, rumen spasm, and lack of treatment. Death occurs between 0.5 and 2.5 hours. The commonly used method of detoxification is to administer 0.5% acetic acid solution or 0.5-2.0% vinegar, and a solution with 20% syrup or sugar is better. Second, pay attention to urea feeding. Dietary crude protein should not exceed 12-13%. When feeding fresh legume grass, silage or ammoniated straw, it is not appropriate to add urea. Appropriate amounts of easily fermentable digestible carbohydrates such as corn and starch should be added to the diet. The feed should be supplemented with an appropriate amount of phosphorus, sulfur and cobalt. The preferred nitrogen-sulfur ratio is 10:1 and the ratio of nitrogen to phosphorus is 8:1. Mix with cereal concentrates and feed at a diet no more than 1% of dry matter. Avoid feeding with urease-rich feeds such as soybeans, etc. Add urea slowly to the required amount, so that the rumen microorganisms have a period of adaptation. Urea should not be mixed with water. Apply urea dry powder to the feed and feed it. Drink water after feeding for 1 hour. Cows under 3 months of age are forbidden to feed urea. Third, new technologies for the rational use of urea 1, ammoniated roughage with urea. It can be directly treated with urea or it can be mixed with calcium hydroxide for composite treatment. 2, the production of urea brick, for cattle to eat. The following formulas can be used: urea 10%, cement 10% (as a binder), molasses 38%, bran 40%, salt 1%, trace elements 1%. 3, the production of gelatinized starch urea. The crushed grain is mixed well with urea, the starch is gelatinized at a certain temperature under high temperature and high pressure, and the urea is packaged therein. The following formula can be used: 75% cornmeal, 24% urea, 1% salt, and sustained release agent. 4, made of biuret and other new products. Biuret is formed by heating and condensation of urea, which is hardly soluble in water and can replace 15-20% of protein in beef cattle diets. The effect is significantly higher than that of urea. 5, coated with urea. The coating of urea with stearic acid and cellulose can reduce the direct contact between urea and urease in rumen fluid, slow down the degradation rate and avoid urea poisoning. Objective To study the application of spiral fixation for central venous catheter in clinical nursing. Central Venous Catheter(CVC) Cvc Catheter,Medical Cvc Catheter,Single Lumen Central Venous Catheter,Triple Lumen Central Venous Catheter Zhejiang Hisern Medical Technology Co., Ltd , https://www.hisernmedical.com