DYNAMICS OF DAIRY PRODUCTIVITY OF COWS OF DIFFERENT LINES

Abstract

The classic method of improving breeds in cattle breeding is in-line animal breeding. This method allows to preserve the hereditary features of the ancestor and enrich the line by accumulation over several generations of valuable heredity and use the most to perfect the breed outstanding the qualities of individual animals and turn individual peculiarities of the ancestors of the lines into the group. The main property of the line is characteristic of its representatives of consolidation of individual economic utility signs due to kinship and directed breeding and selection that makes the line somewhat different from others. In view of the above, the purpose of our research was to study the milk productivity of black-and-white of different line. The research was conducted on Black-and-White cattle of Public Company "Plemzavod Styepnoy" of the Zaporizhzhya region (n = 1928). In cows of different lines, on the basis of retrospective analysis of data for the period from 2004 to 2017 (program dairy herd management "Uniform-Agri") studied dairy performance for the first, second, third and higher lactation. It was found that cows of the studied lines (Bell 1667366, Valiant 1650414, Eleweishn 1491007, Starbak 352790 and Chif 1427381) differed with each other by the duration of lactation and milk productivity indicators. Eleweishn line animals had the longest duration of the first, second, third and best lactation was noted. By this indicator, they dominated the breeds of others lines respectively at 3.2–34.8; 6.7–27.4; 5.0–38.3 and 28.6–47.8 days. Simultaneously, the highest yields for the first (8705.7 kg), the second (9722.7 kg) and the higher (9740.4 kg) lactations were characterized by the cows of the Chif line, and the lowest ones had the Eleweishn line (respectively 8146.8; 8815.5 and 9251.4 kg). Starbak line (9893.0 kg) appeared to be the best by the third lactation yields, after Chif line (29.9 kg). Bell line had the lowest level (9044.9 kg) of yields by mentioned lactations. It should be noted that the highest growth rate is 305 days from the first to the second lactation was observed in the cows of the Chiff line (by 1017.0 kg), somewhat less – at animals of the Starbak line (853.0 kg), even less – in the individuals of Valyat and Eleweishn (819.5 and 668.7 kg respectively), and the least – in Bell line cows (on 282.0 kg). The level of the yield curve between the second and third lactations was significant lower (exception Starbak line) and animals of the above lines was respectively 140.4; 851.0; 230.1; 311.3 and 156.2 kg. It was found that the smallest variability was worth the first lactation and, depending on the line of cows; the coefficients of variability were within19.4–22.8%. For the second lactation, this indicator ranged from 23.3 to 26.8, for the third – from 23.9 to 28.7 and for the best – from 21.3 to 24.7%. Pretty high the variability in the cow's yields of all studied lines indicates the need for their consolidation on this indicator. One of the important features that characterizes the quality of milk is the content of fat. This indicator in the control cows fluctuated, depending on the line and lactation, from 3.74 to 3.82%. The highest fat in milk is for the first lactation was observed in the animals of the lines Eleweishn (3.77%) and Starbak (3.77%),for the second – Starbak line (3.82%), for the third – the lines of Bell (3.79%) and for higher – the cows of Starbak lines (3.77%) and Bell (3.77%). The lowest indicators of the named feature was observed at the beginning of the Bella line (3.75%), for the second and the third lactation – in the cows of the Valiant line (3.76%), and for the best – in the animals of the Chif line (3.74%). The content of protein in the milk of animals of the studied groups is significantly between they did not differ and it, depending on the lactation and line of animals, was within the limits of 3.17–3.21%, which corresponded to the standard of Ukrainian Black-and-White and Holstein breeds. A certain level of intergroup differentiation is also noted in terms of quantity milk fat. For all the lactation under investigation, cows of the Chif line had the highest rates and the lowest ones were the Eleweishn line. Eleweishn line had the lowest amount milk protein for the first, second and best lactation, and by the third Starbak line, and the highest values for the indicated lactation are respectively in the Chif and Starbak lines. Thus, the comparative analysis of the group average on the numerical livestock of cows of different lines showed a significant level of intergroup differentiation by diet, amount of milk fat and milk protein and much less – by the amount of fat and protein in milk. The highest milk yields for first, second and higher lactation showed cows of the Chif line, for the second – the Starbak line, and the smallest – respectively, the Eleweishn and Bell lines. Strength of influence of lines onto the phenotypic variability of the yield, milk fat and milk protein for the first, second, third and best lactation was insignificant, however reliable, on the content of fat and protein in milk – even less and unreliable.