The article presents the results of an experiment to evaluate the effect of the effectiveness of balanced feeding of first-calf heifers with different methods of their maintenance on milk productivity, milk quality and live weight. The duration of the experiment was 365 days. The total number of experimental first-calf heifers was 395 heads, including 121 heads were on the farm with a tethered method of keeping and 274 first-calf heifers were kept at the dairy complex with free movement in the section. They were fed a balanced diet according to detailed standards. An analysis of animal zootechnical indicators revealed their high productivity potential. However, this potential was more fully realized in the conditions of free-range first-calf heifers. During the 305-day lactation period, each cow produced 8,249.9 kg of milk, while the yield of cows on a leash was 19.9% lower. Correlation coefficients have been established between body weight and productivity growth (0.59, p <0.01) in first‑calf heifers with a tethered method of keeping, as well as between the increase in live weight and the yield of milk fat and protein (0.59 and 0.60, respectively, p <0.01). This relationship should be taken into account when raising replacement heifers. When selecting heifers for replacement, it is advisable to consider not only the productivity of their parents, but also their weight. The results of studies on the effectiveness of feeding different types of rations under different housing conditions suggest that it is necessary to organize a standardized feeding system for dairy cows by providing them with differentiated amounts of concentrated feed.

Tsis Elena Yu., Duborezov Vasily M.

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