INFLUENCE OF GENOTYPIC AND PARATHIPIC FACTORS ON THE TRAITS OF MILK PRODUCTION OF COWS UKRAINIAN RED-AND-WHITE DAIRY BREED
Authors: Salohub А. M. 
Published: May 2019

The research was carried out to study the influence of genotypic and paratypical factors on the traits of milk production of cows Ukrainian Red-and-White dairy breed LLC "Mena-Avangard" Chernihiv region. In the conditions of pedigree herd, studied four groups of crossbred animals with conditional share heredity of Holstein breed: I – < 62.5%; ІІ – 62.6–75.0; III – 75.0–87.5 and IV – 87.6 and > .

According to results of researches cow’s crossbred groups of breeding herd Ukrainian Red-and-White breed with a different conditional blood by Holstein breed, was found reliable influence of heredity of improving breed on the level of milk yield and output of milk fat in the dynamics of estimated lactation. Cow’s milk yield with each heredity increase of improver breed grew respectively by 12.5% within crossbred groups. Thus, when comparing cow's group of Holstein blood < 62.5% with their counterparts with blood 62.6–75.0%, advantage was 301 kg in favor of the latter with reliable difference at P < 0.01. Next blood increase to 75.0–87.5% led to a corresponding increase in yield at 262 kg (P < 0.01). Animals with heredity Holstein breed 87.6% higher than the previous generation dominated with a high difference 345 kg of milk (P < 0.001). The blood flow of Holstein breed by 25% resulted in increased milk yield of first-calf cows by 908 kg (P < 0.001). The fat content in milk through this crossing the blood decreased only 0.05% and was not confirmed by reliability, whereas milk fat yield increased with a high significance difference of 31.9 kg (P < 0.001).

According to results of one-factor dispersion analysis, was found that value of yield and output level of milk fat in the first lactation cows of Ukrainian Red-and-White dairy breed, respectively, by 5.5–6.2 and 4.7–9.2%, depend on paratypical factors (year and season of birth and year and season of the first calving), as confirmed by high reliability according to Fisher's criterion.

The level of milk yield and milk fat cows in first lactation significantly - correspondingly 25.3 and 15.8%, depending on the conditional share of heredity Holstein breed. However, the highest rates of influence on yield level and milk fat of the first-calf cows were obtained by size of comprehensive selection index of cow's mother (57.1 and 44.7%), average breeding value of mother for milk yield (64.4 and 45.4%), and for milk fat (53.5 and 38.9%).

With high reliability on indicators of milk production influencing standardized breeding value parent by quantity of milk yield and milk fat (= 0.283 and 0.178).

Calculations show that dispersion of traits development of yield and milk fat of cows first-calf due to the influence of heredity of sires used lines and is respectively 15.7 and 10.9%. Fisher's criterion reliability by these indicators exceed the threshold of the third level (P < 0.001).

Thus, the power of influence heredity of Holstein breed, selection indexes of mothers and parents of cows and father lines on the milk yield level and milk yield output indicating the possibility of effective breeding of the studied dairy cattle by selection of ancestors with a high estimation of selection indices and pedigree value.