Vitamin A can maintain the health and normal physiological function of mucosa epithelial tissues of various organ systems, and maintain the normal vision and reproductive function of cattle. Its lack will cause a series of diseases with weakened mucosal epithelium resistance and pregnancy diseases such as miscarriage and stillbirth.
Only under the following circumstances should be added vitamin A: 1 forage to straw mainly; 2 hay cream after harvest; 3 pure corn silage (even after the crowbar corn), corn and other varieties of concentrate in the proportion is very low; 4 Insufficient colostrum and regular milk feeding, early weaning calves, self-made artificial milk; 5 supplementation in heat stress and transportation is very necessary, generally 0.5 times to 1.0 times the amount.
The main function of vitamin D is to adjust the absorption and metabolism of calcium and phosphorus, and the growth and development of bones. In the absence of yak caused yak snoring and chondrosis in adult cows. It is generally believed that the requirements for yaks and growing cattle are 660 IU per 100 kg of body weight. Dairy cows weigh 30 IU per kilogram of body weight. The exception is that prenatal lactating cows (especially high-yield cattle) should start the injection of vitamin A, D, and E mixed preparations from the first half of the day before birth, which has a significant effect on the prevention of postpartum diseases.
The main role of vitamin E is biological antioxidants and radical scavenging. It can increase the immune response of cells and body fluids. Yak is characterized by muscular dystrophy when it is deficient. Adult cattle can get enough from natural feed. Long-term storage of feed vitamin E content will decrease with the storage time. The amount of vitamin E needed for yaks is 25 IU to 40 IU per kg of dietary dry matter, and 15 IU for dairy cows.
The water-soluble vitamin B family includes thiamine, riboflavin, pyridoxine, biotin, nicotinic acid, vitamin B12, and small choline, all of which play a role in physiological metabolism. However, the rumen microorganisms of cattle can be synthesized. The supply of vitamin B family is usually from cow's milk before the cow's rumen develops normally. Therefore, it should be noticed when warming the cow's milk, generally within 40°C.