According to economic use, pigs can be divided into three types: fat, lean and combined meat. The three economic types of pigs have their own characteristics in terms of body shape, cochineal composition and feed utilization.
(l) Fatty pig: This type of pig is characterized by more rouge fat, general fat accounts for 55%-60% of the proportion of rouge, lean meat accounts for about 40%, the entire shape is square brick type, the body is short and wide, the lower neck is heavy, the hanging meat is more, the ribs are round arched, the back and waist are short and wide, the buttocks are plump, the limbs are thin and strong, the body length is basically equal to the bust circumference; the skin is thin and hairy, the physique is meticulous, the sex is docile, it is resistant to coarse feeding, and the heat resistance is low; the number of litters is low, and this type of pig can effectively use the feed carbohydrates to convert into body fat. The ability to convert lean meat with feed protein is poor, and the feed consumed per unit of weight gain is more. Typically represented by the old-fashioned Baksha pig.
(2) Lean pigs: Contrary to the fat type, the proportion of lean meat in this type of pig accounts for 55%-65% of the rouge, and the fat accounts for about 30%. The body is shallow in length, the whole body is streamlined, the front body is light and the back is heavy, the head and neck are small, the back and waist are long, the chest ribs are full, and the dorsal and abdominal lines are straight. The hind body is plump, the limbs are tall and long, thick and firm, the skin is thin and hairy, the habit is lively, the calving rate is high, the growth and development are fast, but the feed requirements are high. For example, the Yorkshire pig, Duroc pig, long white pig and other pigs imported from foreign countries belong to this type.
(3) Combined pig: This type of pork fat quality is excellent, the flavor is delicious, the meat production and fat production ability are strong, and the fat and lean meat in the rouge body accounts for about half of the points. Medium in stature, broad back and waist, short and thick middle body, plump posterior body, strong physique, docile temperament, strong adaptability. Most of the local pig breeds in China belong to this type, and foreign pig breeds are typical of the Middle Yorkshire pig and the Su white pig.