DAIRY PRODUCTIVITY AND QUALITY OF RAW MILK PRODUCED BY BLACK-SPOTTED FIRST-CALF HEIFERS FED THE PROMELACT FEED ADDITIVE
The main factors of cattle breeding development are optimization of animals’ care and management conditions, preservation and improvement of feeds quality and wide use of different feed additives. The results of a comparative analysis of milk production of Black-Spotted first-calf heifers fed different doses of the Promelact energy supplement as a component of their ration are submitted in the article. The study was carried out under the conditions of the APC farm «Geroy», Republic of Bashkortostan. The additive was introduced into the heifers’ diets during 3 weeks prior to the scheduled calving. The first-calf heifers were given the supplement during the period of 4 weeks after calving and 4 weeks in the second month of lactation in the dose of 200, 300 and 400 ml per head per day. The intergroup analysis revealed that in the 1st and the subsequent months of lactation the highest milk yields were recorded in cows given the Promelact additive, with their subsequent gradual increases up to the 3d month of lactation, having reached the values of 684.33-711.97 kg. On the basis of the data of control milking it was judged on the animals’ dairy productivity by months of lactation and over the periods of 100 and 305 lactation days. In order to improve the quality of milk the raw-stuff composition was analyzed as regards its organoleptic and physical-chemical characteristics in the summer and winter seasons. The sensory evaluation of raw milk quality indicated that the milk, produced both in summer and in winter, was in line with the requirements of current regulatory standards. There was observed the tendency of increased concentration of solids, DNFMS (dry non-fat milk solids) and milk fat in the milk of cows consuming the above energy supplement. The content of calcium was slightly increased. It is shown that in all the year seasons the acidity indices in cows fed the Promelact additive were within the standard limits. The analysis of data obtained in the course of studies indicates that due to the high nutrient content the milk of cows in the experimental group was of higher energy value. As result of the studies conducted it is possible to determine the optimal dosage of the Promelact energy feed supplement to be included in the ration of dairy cows, namely 300 ml per 1 cow per day.