Based on the growth and development stages, fattening pigs can be divided into the early fattening period (before the weight is 60 kg) and the late fattening period (after the weight is 60 kg).

1. Nutritional level

The level of energy and protein in the diet of finishing pigs has a great influence on the carcass quality. Generally speaking, the greater the energy intake, the faster the weight gain, the higher the feed utilization rate, and the more carcass fat. Therefore, by limiting feeding and limiting energy levels in the later stages of fattening, the accumulation of fat can be controlled and the lean meat rate can be increased accordingly. It should be noted that energy levels must be properly controlled. If the energy level is restricted too low, it will lead to an increase in feed intake. However, due to the limited food intake of pigs, the increase in food intake after a certain level cannot fully compensate for the decrease in ingested digestible energy. The pig's weight gain will slow down, fat will decrease, and the carcass will lose weight. Being leaner, the dressing rate and feed utilization rate are reduced. It is uneconomical to use this method to improve carcass quality and increase lean meat rate. Closely related to the energy concentration is the crude fiber content, which also has a greater impact on the carcass lean meat rate. The higher the crude fiber level, the correspondingly lower energy concentration, slower weight gain, and lower feed utilization. Regarding carcass quality, although the proportion of lean meat has been improved, the economic effect of increasing the proportion of crude fiber to increase the lean meat rate is not good. Generally, the crude fiber content of fattening pig diets is 5% to 8%. Similarly, increasing the protein level in the diet can not only increase daily weight gain, but also obtain a carcass with thin back fat, large eye muscle area, and high lean meat rate. However, it is uneconomical to improve meat quality by increasing protein levels. Generally, the protein level of fattening pigs does not exceed 18%. The key to the impact of protein on weight gain and carcass quality is quality, that is, the balance of amino acids. Pigs need 10 essential amino acids. The lack of any one of them will affect weight gain, especially the impact of limiting amino acids such as lysine, methionine and tryptophan is more prominent. The diet should contain sufficient amounts of minerals and vitamins. Especially when certain trace elements in the minerals are insufficient or excessive, it will lead to metabolic disorders in fattening pigs. In mild cases, weight gain is slow and feed consumption increases. In severe cases, it can cause illness and even death.

2. Feeding method

(1) "Linear fattening" feeding method. The so-called linear fattening is to provide corresponding nutrients according to the nutritional needs of fattening pigs at different growth and development stages, and is implemented throughout the period. Rich feeding fattening method. This feeding method has a short fattening period, but the feed utilization is uneconomical and the carcass is fatter.

(2) "Open in the front and restricted in the back" feeding method. In the early stage of fattening, high-energy and high-protein diets are used and fed in an open manner to promote weight gain and sufficient muscle growth. In the later stages of fattening, the feed intake should be appropriately limited or the dietary energy and protein levels should be reduced, allowing pigs to eat freely to reduce fat deposition. This feeding method has a leaner carcass and economical feed utilization, but the fattening period is slightly longer.

3. Feeding technology

The diet during the fattening period is mainly concentrated, and the "linear fattening" feeding method is adopted. In the early fattening period, feed 3 to 4 times a day, with unlimited feeding. Hey, drink water freely. In the later stage of fattening, feed 2 to 3 times a day with unlimited feeding and free access to water. Adopt the "open front and limited rear" feeding method. In the early fattening period, feed 3 to 4 times a day with unlimited feeding and free drinking water. In the later stage of fattening, feed 2 to 3 times a day, feed in limited quantities, and feed 80% to 85% of ad libitum feed intake, with free access to water. Or appropriately reduce the dietary energy and protein levels in the late fattening period and feed them in an unlimited amount.