Solubility and degradability of feed protein and the effectiveness of use of nitrogen in rations when feeding cows during the period of increasing the milk yield

Abstract

Protein solubility significantly affects the efficiency of nitrogen absorption by ruminants. Easily soluble proteins are intensively converted into microbial protein in the forestomach, and less soluble proteins pass to the small intestine where they are digested. For highly productive animals, rations should be created that contain both easily soluble (60 %) and poorly soluble proteins (40 %). The purpose of the research was to study the solubility and degradability of feed protein and the effi ciency of using nitrogen in rations when feeding cows during the period of increasing the milk yield. Under the conditions of the Northern Trans-Urals the effi ciency of milking of cows was studied and a scientifi c basis was given for rations for holsteinized Black-and-White cattle with a daily milk yield of 20–25 kg based on traditional bulk feeds and concentrated mixtures enriched with locally produced rubsen presscake. In green feed, hay, silage, haylage, straw and concentrates, the solubility, degradability and amino acid composition of protein have been established. Comparing the tabulated data on the amino acid composition of the rubsen presscake protein and the data of our research we observed a diff erence in lysine (by 4,66 %), arginine (by 3,3 %), histidine (by 0,75 %) in favor of the rubsen presscake prepared under the conditions of the Northern Trans-Urals. Higher milk yields for the fi rst 100 days as well as for the entire lactation were obtained from the cows of the experimental group, whose ration included a concentrated mixture prepared on the basis of oats, wheat, and rubsen presscake. Thus, in the fi rst 100 days of lactation, 6,27 % more milk was obtained from animals in the experimental group than from cows of the same age in the control group, and in 305 days of lactation by 7,06 % more.