(1) insufficient energy, the growth rate of calves or calves decreased and estrus prolonged. Due to the decrease of protein, fat and minerals in body tissues, dairy cows lose weight, gain weight and reduce milk production, which has adverse effects on health and reproductive performance; If there is excess energy, the excess energy will be deposited in the body (including breasts) of low-and medium-yield cows in the form of fat, which often makes them overweight.
(2) The lack of protein in protein can lead to decreased digestive function, slow growth, weight loss, disordered reproductive function, weakened disease resistance, abnormal structure and function of tissues and organs, which seriously affects the health and production of cattle; Generally, excessive protein will not cause harm to the body, but will cause feed waste, and at the same time increase the amount of nitrogen and phosphorus discharged into the environment and increase environmental pollution.
(3) Although the content of vitamins in vitamin feed is very small, it plays an extremely important role in the regulation of the body, the transformation of energy and the metabolism of tissues. If lacking, it will often lead to corresponding diseases. For example, vitamin A deficiency can lead to dry eye, reproductive dysfunction and rough fur.
(4) Macroelements such as calcium and phosphorus (above 0.0 1% of body weight) and trace elements such as iron, zinc and manganese (below 0.0 1% of body weight) have three major functions. First of all, it is used for the growth and repair of body tissues in vivo. For example, calcium and phosphorus are essential elements for bone development. Second, some are physiological metabolism or enzyme components, such as iron and zinc, which are components of various enzymes and participate in carbohydrate metabolism; Copper is one of the components of hemoglobin, and its deficiency often leads to anemia and abnormal bone metabolism. Thirdly, minerals also play an important role in dairy production. For example, the mineral content in dry matter of milk is 5.8%.
(5) The water content accounts for about 60% ~ 70% of the cow's weight. If the water content accounts for 65,438+00% of the body, the cow will dehydrate and die. More than 85% of milk is water. Therefore, water plays a particularly important role in nutrients. The water requirement of dairy cows is influenced by climate, milk yield, feed intake and the nature and types of forage. In production, cows are generally allowed to drink freely to meet their quantitative needs. Also ensure that the water quality is good, clean and pollution-free. The water temperature in winter shall not be lower than 5℃.