Influence of absorbing crossing on milk production and live weight of Ukrainian Black andWhite dairy cows
The research was conducted in breeding herds of Ukrainian Black and White dairy breed at the LLC AF “Matiushi”, LLC “Sukholiske” and LLC AF “Glushky” in Bila Tserkva District, Kyiv Region. The research was based on dates of zootechnical and pedigree records. Depending on Holstein inheritance there were formed three groups of heifers: Ukrainian Black and White dairy breed (UBWD) with Holstein inheritance of 75.0-87.4 %, UBWD with Holstein inheritance of 87.5-99.9 % and Holstein breed (100 %). It was established that increasing of Holstein breed cognation provides higher level of milk yield, amount of milk fat and protein. In the herd LLC AF “Glushky” UBWD cows with Holstein inheritance 100 % had an advantage over UBWD cows with Holstein inheritance 75.0-87.4 % on milk yield by 927 kg (P<0.05), mass fraction of fat - by 0.16 % (P<0,001), amount of milk fat - 42 kg (P<0.01) and milk protein - 27 kg (P<0,05) and they dominated over the UBWD cows with Holstein inheritance 87.5-99.9 % on milk yield by 87 kg, amount of milk fat - 3 kg, milk protein - 2 kg. In the herd LLC AF “Matiushi” cows with Holstein inheritance of 100 % were dominated over the cows with Holstein inheritance of 75.0-87.4 % on milk yield by148 kg, amount of milk protein -4 kg. They had an advantage over heifers with Holstein inheritance of 87.5-99.9 % on milk yield by56 kg, amount of milk protein -2 kg but the differences for the researched parameters were improbable. The same trend was observed in LLC “Suholiske”. An important breeding and economic feature of cows is live weight, which is related to the level of milk production. Definition of breeding feature of “live weight” for dairy cattle is based on the presence of positive correlation between the live weight and milk yield. In the herd LLC AF “Glushky” UBWD cows with Holstein inheritance of 100 % had higher live weight on 58 kg (P<0,001) compared to cows with Holstein inheritance of 75.0-87.4 % and 22 kg higher compared to cows with Holstein inheritance of 87.5-99.9 %. In the herd LLC AF “Matiushi” this advantage was 47 kg (P<0.05) and 20 kg, in the herd LLC “Suholiske”- 48 kg (P<0.01) and 8 kg, respectively. As a result of own research there was found the relation between milk production of firstborn with their live weight. In three herds higher milk production was found in heifers with live weight 551 kg or more. In the herd LLC AF “Glushky” milk yield of heifers increase as well as live weight regardless of Holstein inheritance. Thus, cows with Holstein inheritance share of 75.0-87.4 % and live weight 551 kg or more are characterized by higher milk yield on 226 kg, mass fraction of fat - 0.1 %, milking index - on 27 kg compared to cows with live weight 500 kg and less. Cows with Holstein inheritance of 87.5-99.9 % and live weight 551-600 kg also had higher milk yield on 176 kg, milking index - on 46 kg compared to cows with live weight 500 kg and less. In the herd LLC AF “Matiushi” cows with Holstein inheritance of 75.0-87.4 % and live weight 551-600 kg had a higher milk yield on 196 kg, milking index- 14 kg compared to the heifers with live weight 500 kg and less. Cows with Holstein inheritance of 75.0-87.4 % and live weight 551 kg or more had an advantage by milk yield on 161 kg, mass fraction of fat - 0.1 %, milking index - 24 kg compared to cows with live weight 500 kg and less. Cows with Holstein inheritance of 100 % and live weight 551 kg or more were dominated over the cows with live weight 500 kg and less by milk yield on 159 kg, mass fraction of fat - 0.1 %, milking index - on 5 kg. The same trend was observed in LLC “Suholiske”. According to the results of variance analy s is, the power of influence of Holstein inheritance depends on the researching parameters and herds. The largest influence on live weight, milk yield, mass fraction of fat and protein was found in the herd LLC “Suholiske”; the least impact on live weight, mass fraction of protein and amount of milk protein- in the herd LLC AF “Glushky”; the least impact on milk yield, mass fraction of fat and amount of milk fat - in the herd LLC AF “Matiushi”. Thus, as a result of own research there was found a positive effect of absorbing crossbreeding Ukrainian Black and White dairy breed with Holstein breed on milk yield, amount of milk fat, milk protein and milking index. Higher live weight had heifers with Holstein inheritance of 100 % compared to the cows with Holstein inheritance of 75.0-87.4 % and 87.5-99.9 %.