DYNAMICS OF THE QUALITY OF COW COLOSTRUM DEPENDING ON THE TIME OF THE FIRST MILKING AFTER CALVING

The aim of the study is to increase the viability of newborn calves and the quality conditions for young-stock breed-ing. Dairy and combined breeds zoned in a climatic area of Central Volga and South Ural were studied. Four ex-perimental groups contained down-calving cows were established: the first group- black and white, the II group – Bestuzhev, III group – Holstein, IV group – Aurshire breeds. After calving the first milking in subgroups was carried out in 30, 60, 90, 120, 150, 180 min., taking the selected average samples of a colostrum for the analysis. It was es-tablished that the first yield colostrum from different breeds selected considerably differs, especially for protein con-tent and its fractions. The Bestuzhev breed surpassed the analogs, respectively by 6.1; 6.6; 0.7%. There is a de-crease of protein portion with time increase to the first milking. The difference amounted to 0.9; 2.6; 0.8; 2.1% in 120 min. in regard to different breeds and in 180 min. – 2.4; 5.2; 2.3; 4.8%. In 180 min in regard to the breed groups es-tablished. Immunoglobulins which form kolostral immunity for calves are very important component among protein fractions. It is established that depending on time of the first milking their content decreases even more considera-bly. In 120 min. after calving the content of immunoglobulins in a colostrum of cows decreased, respectively by 5.2; 12.9; 7.0; 9.7%, and in 180 min. – on 11.1; 28.9; 14.3; 27.0%. At the same time the quality of Aurshire breed colos-trum approached to the lowest point of physiological norm, black and white – was recognized as incomplete, and Holstein breed – was considered unsuitable for newborns at all.