1. Principles of formulation
The formulation principle should conform to the Feed Nutrition Composition Table and the Dairy Cattle Feeding Standard, and be combined with the actual production of dairy cows to design the dietary formula. Diet formulation should ensure rich and comprehensive nutrition, a reasonable proportion of concentrate and roughage, so that the nutrition needed by dairy cows can be satisfied, to ensure their physical health, while the stability of milk ingredients.
The dairy cow diet contains an appropriate amount of corn silage, which is suitable for feeding more than 20 kg per day in the lactation stage on average. It is necessary to ensure that dairy cows feed more than 3 kg of hay per day. It is best to feed Leymus Chinensis, alfalfa and other high-quality hay, and pay attention to a variety of combinations. Besides, the ratio of energy to protein in the diet should be reasonable, because excessive protein will lead to ketosis and other metabolic diseases in dairy cows, while excessive fat will lead to lower milk protein rate.
The proportion of dietary formulation is usually 45%-60% of roughage, 35%-50% of concentrate, 3%-4% of mineral feed, 1% of trace elements and vitamin additives. The ratio of calcium to phosphorus should be kept at 1.5-2.0. Attention should be paid to the inability to add the animal-derived feed to dairy cows during feeding. For the purchased mixed concentrate, the test report must be checked to determine the nutrient content and whether to add animal-derived and drug ingredients. According to the nutritional needs of dairy cows, roughage, concentrate, and supplementary feed were cut and stirred by special feed mixing machines following reasonable proportions and requirements, to make them fully mixed and evenly, and become a nutritionally balanced diet. The water content of the total mixed diet should be controlled between 40% and 50%.
Before the dairy cow diet is prepared, the contents of various nutrients in the diet should be defined first, which is also the basis for the preparation of the dairy cow diet. The simplest way to determine the nutritional level is to refer to the feeding standards.
Selection of raw materials.
Dairy cows need a lot of nutrients, which can be classified into energy, protein, vitamins, macroelement and trace elements. To fully meet the nutritional requirements of dairy cows, the feed raw materials for the formulation of diets must contain energy feed, protein feed, trace element additives, and mineral feed. Through investigation in most feed resource areas of China, the basis of material selection is the use of corn, cake, bran, calcium hydrogen phosphate and bone meal, shell powder or stone powder, salt and additive premix with trace elements.
Design of formula.
The original formula of the dairy cow diet needs to be designed by relevant calculation. In general, after determining the nutritional level and feed raw materials, it is necessary to design the original formula through various calculation methods to meet the nutritional needs of dairy cows.
Determination of formula.
For the designed formula of the dairy cow diet, it must be validated by experiments and can achieve the desired effect, so that it can be formally applied. If it is found that dairy cows suffer from growth retardation, rejection of feeding, poor lactation quality, and diarrhea, the causes should be separated and identified. If it is caused by problems in the dietary formulation, the problems should be corrected immediately, and the experiment should be conducted again until the effect is satisfactory.
The feed should be less but better.
If too much or too little concentrate is added to the diet of dairy cows, it will affect the digestion and utilization of roughage and rumination. Too much concentrate feed can lead to abnormal metabolism in the rumen of dairy cows, and make excess nutrients in the body become residues that can not be digested and absorbed, resulting in an increased burden on the liver and kidney.
Besides, poor circulation throughout the cow's body can cause breast edema, ovarian dysfunction, blood milk, and estrus is not obvious, abnormal, unable to pregnancy and so on. Therefore, the use of concentrate should be better, that is, the quality of feed raw materials should be as good as possible, to increase the energy and protein level of concentrate unit, and the use of concentrate should be as low as possible, that is, to reduce the proportion of concentrate in the diet, and pay attention to the need to control below 50% in any case. Roughing, expanding or flattening before use, can improve the utilization rate of feed, and also need to have a variety of raw materials for the rational formulation to ensure diversification.
Nutrition intake of dairy cows is not only related to the nutrient level of concentrate supplement but also closely related to feed intake. The key factor determining feed intake is feed palatability. Therefore, we should try our best to ensure that the dairy cow feeding diet is palatable. Usually, a variety of good palatability feeds are used in the formulation of diets to enhance palatability. The diet usually contains more than 2 kinds of roughage, 2-3 kinds of juicy feed and 4-5 kinds of concentrate feed. Attention should be paid to the uniform mixing of concentrate feed. Molasses, beet pulp and other sweet feed can also be added to concentrate.
It is better not to add additives in the preparation of diets to ensure feed stability.
To ensure the safety and non-pollution of dairy products, as far as possible, no feed additives and antibiotics should be added in the formulation of diets, and the standards formulated by the state should be strictly observed when using them.
It should be adjusted appropriately according to the weight of dairy cows.
Dietary dry matter content and volume must be able to ensure that the normal digestive process of dairy cows needs to be met. If the digestive tract is overfull or not, its health and production performance will be affected, because the milk production of dairy cows is closely related to their dietary dry matter requirements. The basic feed of dairy cow diet is forage, and more than 60% of the dry matter in the diet comes from forage. Usually, dairy cows are fed 1.5-2.0 kg of hay per l00 kg of body weight. A silage of 3-4 kg or 4-5 kg of tubers or roots can be used to replace 1 kg of hay. Crude fiber is the main nutrient to ensure the normal digestion and metabolism of dairy cows. The dry matter in the diet contains 15%-24% of crude fiber, and it is adjusted according to the milk production of dairy cows.