A new method of feed evaluation in milk production

Abstract

Purpose. Development of a new method for estimating 1 kg of feed dry matter in milk production. Methods. The standard methods for evaluating feed based on the indicators of crude protein, fat, sugars, crude fiber, feed units, gross, metabolic, digestible and net energy of lactation and others. Modern methods of feed evaluation are based on metabolic energy, but they have some controversies. Whereas the method on the base of milk production is quite different. Milk protein synthesis occurs only from the amino acids of feed protein and bacterial protein of rumen biomass, in the synthesis of which non-protein feed ingredients are used. When converting the amino acids of crude feed protein into any type of energy, the reverse synthesis of amino acids from energy does not occur, so evaluation of feed in milk production on the base of the crude protein content in feed is biochemically justified. Results. The essence of the new suggested method of feed evaluation in milk production of 1 kg of feed dry matter is expressed by the product of 3.1 MJ of energy of 1 liter of milk on the ratio of gross energy of crude feed protein to gross energy of crude diet (%) with hemicellulose in the amount of 1/2 of the estimated feed, as this hemicellulose is not broken down in the rumen, because it is structurally combined with the cellulose of crude fiber of the evaluated feed. Typical rations for cows with a content of 17.0 were taken for evaluation; 23.0; 26.0; 30.0 and 32.0% of crude fiber and the same rations with the inclusion of hemicellulose in the amount of 1/2 of the content of SC in the evaluated feed and obtaining the gross energy of the total amount of structural carbohydrates. Conclusions. The essence of the suggested method of feed evaluation in milk production of 1 kg of feed dry matter lies in taking into account hemicellulose in calculation as this hemicellulose is not broken down in the rumen because it is combined with cellulose of the raw fiber of the evaluated feed. The confirming factor of validity of the new method of estimation in milk production of 1 kg of feed dry matter is the cost of crude protein for the formation of 1 liter of milk. Crude protein is found in the structure of cellulose and hemicellulose fibers. The high level of utilization of crude protein for milk protein synthesis is characteristic of concentrated feeds when used in high-yielding cows feeding.