(1) Economic hybridity The heterosis of fatty traits in local pig breeds in China is very tenacious. By relying on crossbreeding of domestic breeds, it is not possible to produce ideal lean lean commercial pigs. With the use of foreign lean pigs hybridized with local pig breeds in our country, the lean meat percentage of the hybrids is not too high, but the lean meat percentage has been significantly improved by the hybridization between foreign lean pig breeds and China's hybrid breeders. For example, Landrace, Yorkshire, and Duroc pigs were crossed with Beijing black pigs, Jilin black pigs, Wenzhou white pigs, and Shanghai white pigs, respectively, and the lean meat percentage of hybrid pigs could reach more than 50%. However, there are considerable differences between individuals of each breed, and degradation will occur if attention is not paid to breeding. Therefore, whether it is pigs imported from abroad or pigs cultivated in China, it is necessary to continue breeding and improvement. (2) The proportion of carcass fat fed to protein feeds increased with age and body weight at different growth stages, but the proportion of carcass protein decreased with increasing age and resting weight. Therefore, special attention should be paid to the proportion of feed protein at different growth stages. The proportion of suitable feed protein is 5-20 kg of body weight 22%; 22-55 kg of body weight 10-17%; 55-90 kg of body weight such as in order to ensure the quality of carcass quality feed protein can be controlled at 16%, such as to increase Heavy, can be controlled at 14%. The supply of protein is actually the function of amino acids. Therefore, a variety of feeds are required, such as corn and bean cake. Lysine is the key point in the pig's feed. Pigs need a large amount of lysine, and lysine supplementation can work. When formulating feeds, pay attention to feeds containing more lysine, such as bean cakes, peanut cakes, rapeseed cakes, broad beans, black beans, adzuki beans and so on. (3) The growth of pigs is guaranteed in the early and middle stages of nutrition, and the pigs reared to limit the age of 3 to 6 months grow faster and should be given adequate nutrition and an appropriate proportion of protein, which will help increase the lean meat percentage. In the late growth stage of fattening pigs, the higher the daily weight gain, the higher the percentage of carcass fat, and the method of restricting rearing and limiting the energy and feeding amount. Limiting energy is to reduce the energy per kilogram of feed to about 2.8 megacalories. The approach is to feed more green feed and increase bran ratio. Limiting the amount of feed is only giving 85% of the usual feed intake. This increase in weight is slower, but it can increase lean meat and feed conversion rates and increase economic efficiency. In some regions, rough and refined methods are used to feed roughage during the most muscular growth stage, which affects the growth of lean meat. In the later period, when pigs are fat, they are given rich feed to promote fat growth. This method is unscientific and worth improving. (4) to grasp the appropriate slaughter period, the appropriate slaughter period can be due to pig size and maturity of different large pigs, weight 50-90 kg, muscle growth and development of the period, after which is the accumulation of fat Prosperous period. Proper fat deposition improves meat quality. Therefore, the introduction of large lean-type pigs, weighing 100-105 kg slaughter is more appropriate. Medium-sized pigs are generally slaughtered before 90 kg. Small pig breeds, precocious and easily fattened, are slaughtered with a body weight of 65-75 kilograms. They can be slaughtered with large-medium crossbred pigs at 70-80 kg.