First of all, it is related to the preciousness of meat. Cattle is an important means of production in the farming era. In many dynasties, it was forbidden to slaughter cattle without permission. As the Book of Rites said, even princes would not kill cattle easily if they had nothing important to do. As early as the Han Dynasty, cattle had been protected by legislation, and China law stipulated that "no less teeth should be slaughtered". The punishment for killing cattle in the Han Law is very severe, and those who violate the ban will be punished and pay the price of their lives. During the Tang and Song Dynasties, cattle were forbidden to be slaughtered regardless of their age, weakness, illness and disability. Only cows that die naturally or die of illness can be skinned for sale or eaten by themselves. Rare things are precious, and beef naturally ranks among the best in the meat list. There are two unusually rich menus in "Great Tactics" and "Evocation of Soul" in Songs of the South, including: eight-treasure rice, stewed beef tendon, May soup, stewed turtle, roasted mutton, vinegar goose, roast chicken, mutton soup, twisted dough, roasted quail and stewed dog meat. Beef is at the top of the menu, and its importance is self-evident.

The development trend of meat in Tang and Song Dynasties-beef and mutton is still the mainstream.

This kind of eating habit was formed in the pre-Qin period and deeply influenced later generations. On the basis of famous barbecues in the Tang Dynasty, the recipes are as follows: tender beef intestines (cooked with sheep oil), prawns (baked with live shrimps), white dragon loin (made of tenderloin repeatedly slapped), shredded sheepskin (fried shredded mutton, cut into a foot), snow baby (bean sprouts with frogs) and snow baby. Cattle, sheep, chickens, quails and even frogs are short of pork. The diet culture of the Han nationality developed extensively and profoundly in the Song Dynasty. Because of the ban on beef, mutton became the main meat of the royal literati in this period. Eating sheep in the Song Dynasty was a popular custom of the royal family. In Song Zhenzong, the royal chef slaughtered 350 sheep every day, while in Injong, he slaughtered 280 sheep every day, while in Yingzong, it was reduced to 40 sheep every day. In Zongshen, although pork consumption was introduced, the royal chef consumed "434,463 Jin and mutton 4 Liang" a year, and pork only used "4 1 365,438 Jin", which was less than mutton consumption.

Pigs have existed in China since ancient times, but according to various records, they were not accepted by the literati and the rich gentry until the Northern Song Dynasty, and were only the staple food of the poor. There are two historical materials:

First, Song Renzong wants to eat mutton in the middle of the night, but he is afraid that once he eats it, it will become a kind of regulation, and it will be provided every night, which will increase the economic burden.

Second, Dongpo meat is quite popular now. As we all know, Su Dongpo in the Northern Song Dynasty was a very talented person, but he was repeatedly frustrated and often demoted. He lives in poverty and can't afford mutton, so he can only eat pork.