1. Addition of fat: It is best to pass through the coated fat; According to Jenkins et al. (1984), adding uncoated fat has a strong inhibitory effect on ruminal fermentation. Because the fatty acids produced by the degradation in the stomach of cancer have toxic and inhibitory effects on rumen bacteria, especially cellulolytic bacteria, the digestibility of cellulose is significantly reduced. At the same time, the production of methane, hydrogen and VFA decreased, the ratio of acetic acid and propionic acid decreased, and the milk fat percentage also decreased. Palmquist et al. (1980) concluded that the results of others' studies also suggested that fat can reduce microbial activity and cellulose digestibility declines. The addition of saponification, hydrogenation, formaldehyde and other fat treatment, so that the fat in the rumen does not dissociate and hydrolysis, directly into the small intestine to be digested and absorbed, not only provide energy, but also avoid digestion and absorption of cellulose and other nutrients The impact thus increases the production performance of dairy cows. Therefore, in the production of fat, must be added to the coated fat, if not coated, it is necessary to control the amount of addition, the second is to increase the content of calcium and magnesium in the daily amount. 2, the amount of fat added: the amount is not the more the better, the amount of excessive, especially uncoated fat, resulting in rumen burden, reducing microbial activity and crude fiber digestibility, so that dry matter mining Food intake decreased. Milk production also decreased. The suitable amount of fat for dairy cows is approximately 3%--4%, which means that each cow can add 0.45 to 1.36 kilograms per day. If the added amount exceeds 4%, the bypassed portion should be replaced by the coated fat. At the same time, it is necessary to pay attention to the milk yield of the dairy cow. The FCM/day milk cow with an average milk yield of less than 25.2 kg 4% does not need to add fat, and the milk yield exceeds this. For the value, fat should be added to increase the energy concentration of the diet to meet its production needs. 3. Pay attention to the degree of fat saturation: It has been reported that 2.4% of six fatty acids (8:0, 10:0, 12:0, l4:0, 16:O, 18:O) are added to the dairy cow diet. Calcium salt, the results showed that the fatty acids of l4:0,16:O,18:O were increased by 3.58%-3.67% compared with the control group, and the fatty acid content in milk fat was also increased accordingly; the ratio of 8:0 increased by 3.37%. The 10:0 and 1 2:0 decrease by 2.8%-3.07% instead. Japan's "Scientific Feed" (1991) also reported that in the United States, some people added 2% - 3% of granular hardened fat in the dairy diet, which has a good effect on improving milk yield, milk fat percentage and conception rate. It shows that adding fat to dairy cows' diets is best for long-chain saturated fatty acids. 4. Quality of fat for feeding: According to the report of “Scientific Feed†in Japan, the quality standards of the feed fat recommended by the relevant US Department of Agriculture: First, the total fatty acid content is above 90%, the moisture content is less than 1.0%, and the insoluble impurity is less than 1.5%. Second, the unsaponifiable of animal and plant fats were less than 1.0% and 4.0% respectively; the third was stability--AOM value, and the peroxide value was less than 20meq/kg in 2O hours of test; 4) the content of pesticide residues and polychlorinated biphenyls was in accordance with Feeding specifications. Therefore, when using fats, pay attention to the quality of fats, especially if you cannot use rancid fats, otherwise you will lose out. 5 Pay attention to the composition of the diet: Add fat to consider the type of roughage in the diet. According to reports, when corn silage is used as the main feed, only the addition of fat from cattle and sheep can increase the milk yield, and cocoon and cottonseed have a good synergistic effect. It can accelerate the digestion of cottonseed, which may be due to the high calcium content in the earthworm. Can form insoluble calcium soap with fatty acids, so that fatty acids easily pass rumen. 6 Step-by-step feeding of fat: Gradually increasing fat intake can avoid poor palatability. One third of the feed was started at the beginning of feeding, and the full amount was used within three to four weeks. This can be used to feed the ration in three stages, which can significantly reduce the discomfort of the cow. Hainanmycin Premix,Hainanmycin Feed Addtitives,Hainanmycin Anticoccidial,Hainanmycin Chicken Shandong Shengli Bioengineering Co., Ltd , https://www.shenglipharm.com