Milk production of dairy cows is affected by many factors, among which the nutrition and disease of dairy cows have the greatest impact on milk production. Various components in milk are converted from nutrients in feed, synthesized and transformed within cells, and secreted through the mammary gland. Dairy cows in the lactation period have reduced energy intake and increased demand. If dairy cows suffer from insufficient feed and nutritional deficiencies for a long time, and their energy is in a state of negative balance, milk production and milk component content will be affected. Therefore, lactating dairy cows need to be properly fed according to their body weight, milk production, milk fat rate, milk protein rate, and body condition.

Lactic acid bacteria can decompose protein, sugar, fat and other nutrients in feed, significantly improve food digestibility and biological titer, and promote digestion and absorption. Adding mixed lactic acid bacteria to the diet of dairy cows will improve milk production and milk composition, with milk production increasing by 0.73 kg/day and dry matter intake decreasing by 0.42 kg. After fermentation of corn flour and wheat flour, the lysine content increased by 72 and 85 respectively, the methionine increased by 40 and 46 respectively, the free nitrogen increased by 1.6 and 1.4 times, the free iron increased by 1.3 and 0.9 times, the free calcium increased by 1.5 and 1.2 times, and the sulfur content increased by 1.6 and 1.4 times. Both amines and riboflavin were increased, and the overall nutritional value was significantly improved.

Lactobacillus can enhance the stability of some vitamins and improve the biological activity of mineral elements. The organic acids produced during metabolism can also strengthen intestinal peristalsis and reduce intestinal pH, which is beneficial to the absorption of nutrients. Digest and absorb, improve the palatability of feed, and increase feed intake of livestock.

After feeding cellulolytic bacteria for 40 days, the milk production increased by 6.57%, the milk protein content increased by 5.67%, and the milk fat rate increased by 4.49% compared with those before and without feeding. The research results show that the sweet sorghum residue biological feed fermented by Yifuyuan em bacteria increased the feed intake and milk production of dairy cows. Compared with the cows in the normal feeding group, the feed intake of the cows in the experimental group increased by 11.4%, and the milk production increased. 14.2%, the milk protein content has increased by 14.03%; the butterfat rate in milk has increased by 16.3%. Adding lactic acid bacteria and other beneficial probiotics to feed can effectively increase the milk production of lactating dairy cows, optimize the nutritional components of milk, and improve the nutritional value of milk.