Biochemical blood values of ewes in the first month of lactation and their relation to milk productivity

Milk productivity and a set of biochemical blood parameters characterizing the metabolic status were studied in suck-ling semi-fine-fleece wool-and-meat ewes of the first month of lactation (n = 80) of the experimental herd of L. A. Kaneva farm in the Ust-Tsilemsky district of Komi Republic. The ewes with lambs were kept in the same room in similar conditions of keeping and feeding. To characterize the metabolic type, all controlled ewes were divided into three groups depending on the level of their milk productivity. There was no significant linear variation of the metabolites during the transition from group to group. As a result of studying the associations between milking capacity and biochemical parameters of blood serum within the groups, in high-milking ewes of group 3, statistically significant correlations were found with the level of urea (r = -0.47, P 0.05). As a result of combining urea, alkaline phosphatase (AP) and glucose into one complex index – AP*glucose/urea, it was possible to increase significantly the correlation coefficient with milking capacity to 0.61 at P < 0.001. The obtained results indicate that high-milking ewes have metabolic features developed as the result of the body's adaptation to intensive lactation activity. These features are expressed in the interrelated fluctuation of three metabolites – urea, AP and glucose. It is assumed that urea indicates more efficient assimilation of nitrogen of the diet with an increase in milk productivity, intense inclusion of amino groups into metabolic processes necessary for the synthesis of milk proteins. Glucose and alkaline phosphatase indicate an increase in the intensity of cellular metabolism.