@article{Sharapa_Boiko_Demchuk_2022, title={REPRODUCTIVE ABILITY AND PRODUCTIVITY OF COWS FOR THREE LACTATIONS, DEPENDING ON THE AGE OF CONCEPTION OF HEIFERS}, volume={63}, url={https://abg-journal.com/index.php/journal/article/view/362}, DOI={10.31073/abg.63.17}, abstractNote={<p>In research and production experiments on 911 cows of the Holstein (H), Ukrainian Black-and-White (UBWD) and Ukrainian Red-and-White (URWD) dairy breeds, their reproductive capacity and milk productivity during the third and three lactations, depending on the age of the fetus, were studied calving heifers.</p> <p>The average duration of the service period (SP) was 130 days, and the lactation period (LP) was 334 days in the cows of the State Enterprise "Chaika" of the UBWD breed for the third lactation. Milk yield was equal to 8334 kg with a fat content of 3.78%, and daily yield of milk was 24 kg. The best were cows that were impregnated with heifers at the age of 12–18 months.</p> <p>For three lactations, the average duration of SP was 154 days and LP was 361 days, and the milk yield was 9315 kg with a fat content of 3.78%. The daily yield of milk was at the level of 25.7 kg. Younger cows had the best performance.</p> <p>In the cows of CJSC "Agro-Region" of the third lactation (142 cows), the post-calving recovery period (RP) lasted an average of 78 days, the service period – 114 days. and lactation – 328 days. with a yield of 7.558 kg, the fat content of milk was 3.77%, and the daily yield was 23.1 kg.</p> <p>The best economic indicators were cows of the Holstein and UBWD breeds. For three lactations in 508 considered cows, the average duration of RP was 74 days, SP – 120 days and LP – 338 days. The yield of milk was at the level of 7.823 kg with a fat content of 3.75%, and the daily yield was 23.5&nbsp;kg. The best indicators for the third lactation and for three lactations were cows of the Holstein and UBWD breeds.</p> <p>Experiments proved the economic feasibility of inseminating heifers at the age of 14–18 months, and well-developed heifers at 12–13 months, which positively affects the reproductive capacity and milk productivity of cows.</p&gt;}, journal={Animal Breeding and Genetics}, author={Sharapa, H. S. and Boiko, O. V. and Demchuk, S. Yu.}, year={2022}, month={Aug.}, pages={185-190} }