INFLUENCE OF PATERNAL ORIGIN ON THE MANIFESTATION OF ECONOMIC USEFUL TRAITS IN THEIR DAUGHTERS IN ORGANIC AND CONVENTIONAL MILK PRODUCTION
Authors: Kucher D. , Kochuk-Yashchenko O. , Slusar M. , Tkachuk S. , Karykh K. 
Published: December 2022

Introduction. The article presents the results of the study of the degree of influence of paternal origin on economically useful traits of first-born cows of the Simmental breed in organic and conventional herds.
Materials and methods of research. The research was conducted in herds of the Simmental breed of PE "Galex-Agro" (organic milk production, n = 272) and STOV "Myroslavel-Agro" (conventional milk production, n = 120) of the Zhytomyr region. The most numerous breeding bulls in terms of the number of daughters were selected for the research in the conditions of organic production of PE "Galex-Agro": Dollar CZ 120158021 (18 daughters), Dustin CZ 500883061 (10 daughters), Incubus CZ 577790071 (20 daughters), Rumgo AT 168213272 (19 daughters), Brilliant CZ 141771694 (11 daughters), Expert CZ 510887061 (18 daughters), Emilik CZ 520019032 (19 daughters); in the conditions of conventional production of the "Myroslavel-Agro" STOV: Bavor CZ 105770664 (10 daughters), Morello CZ 12451683 (11 daughters), Radi CZ 20997683 (16 daughters).
Research and methods of research. The data obtained convincingly testify to the genetic influence of breeder bulls on the manifestation of milk productivity, reproductive capacity, and dynamics of live weight of heifers during their rearing in conditions of organic and conventional milk production.
We managed to perform intergroup differentiation of breeding bulls according to the milk productivity of daughters and to identify the best ones and confirm their influence on the manifestation of these traits. A statistically significant difference (from P < 0.05 to P < 0.001) in terms of milk productivity between daughters of the best and worst breeders according to these characteristics was found in 100% of cases.
The best manifestation of the quantitative signs of milk productivity was characterized by the daughters of the breeding sire Brilliant CZ 141771694, and the worst by Dustin CZ 500883061. A statically significant difference of 0.20% was found in the milk protein content in favor of the daughters of the breeder Dollar CZ 120158021 compared to the daughters of the breeding sire Dustin CZ 500883061.
In general, the daughters of breeder bulls represented by Galex-Agro PE were distinguished by higher milk productivity compared to their peers in the conditions of the Myroslavel-Agro farm. Since different breeding bulls were used in organic and conventional milk production, it was not possible to identify prepotent bulls simultaneously in both systems. However, there is a tendency that under the conditions of both farms, the descendants of the Redada line turned out to be the best (Rumgo AT 168213272 – PE "Galex-Agro", Radi CZ 20997683 – STOV "Myroslavel-Agro"). In the conditions of PE "Galex-Agro", it is worth noting the bull Brilliant CZ 141771694, whose daughters had a statistically significant advantage over the peers of other bulls in the vast majority of quantitative signs of milk productivity. The obtained data convincingly testify to the expediency of using the mentioned bulls in the conditions of both farms.
The assessment of the reproductive capacity of the daughters of various breeder bulls under conditions of organic production showed that the daughters of all bulls, except for Expert CZ 510887061, were characterized by close to the desired length of biological periods of reproduction. The most desired parameters of reproductive ability were characterized by the daughters of breeding bulls Dollar CZ 120158021 and Rumgo AT 168213272, the least–daughters of Expert CZ 510887061. It is worth noting that when comparing group averages in 84% of cases it was possible to establish a statistically significant level of intergroup difference between the daughters of the best and worst bulls – breeders according to the duration of their biological periods of reproduction.
In the conditions of conventional milk production of the "Myroslavel-Agro" dairy farm, a worse manifestation of the reproductive ability of the daughters of breeder bulls was established than in the conditions of the "Galex-Agro" PE. The half-sisters of the sire Radi CZ 20997683 were characterized by a slightly better manifestation of the signs of reproductive ability, and the worse - Bavor CZ 102554690. There was a slight intergroup fluctuation in the average values of the signs of reproductive ability.
There is a significant level of intergroup differentiation of half-sisters by the father of different bulls for the live weight of their daughters in the period of their rearing from birth to 18 months of age. It is worth noting that in the conditions of the Galex-Agro PE, in all cases of comparisons based on the signs of milk productivity, it was not possible to establish non-consolidation in the daughters of bulls: Rumgo AT 168213272, Brilliant CZ 141771694, and in the conditions of the Myroslavel-Agro STOV – Rada CZ 20997683, these bulls were also characterized by the highest milk productivity. Therefore, the use of these prepotent improvers for milk productivity will contribute not only to an increase in productivity but also to its consolidation.
Conclusions. In the conditions of organic management of the dairy industry (PP "Galex-Agro"), there is a statistically significant effect of sire's origin on the yield in 305 days of lactation, milk fat, protein content in milk, milk protein, total production of fat and protein (Р < 0.01 ). The highest influence of paternal origin among the traits of milk productivity was on the protein content of milk which amounted to 40.5%. As for the conventional farm (STOV "Myroslavel-Agro"), there was no statistically significant effect of paternal origin on most of the milk productivity traits (P > 0.05).