Milk productivity and reproduction function of black-and-white holland cows of different genotypes

Abstract

Relevance. The black-and-white breed of cattle in our country has been improved by the Holstein breed for several decades. Along with its positive impact, there are also negative aspects of the process. Thus, the duration of the use of cows was reduced, resistance and reproduction function decreased.In order to find breeding methods to increase the safety of cows and improve the function of reproduction, studies were carried out in herds of three regions with high bloodliness for the Holstein breed (97% HL, 3% BW) and descendants from Montbéliarde bulls (50% MB, 49% HL, 1% BW) and promising genotypes of cows were identified.Experimental studies have been carried out since 2016 with loose and tethered animals.In the experiment, with loose keeping in daughters from Montbéliarde bulls (genotype 50% MB, 49% HL, 1% BW), with almost equal productivity, the age of 1 calving was 41 days less, the service period was 25 days less, the safety to 2 lactations was higher, because by its beginning, 16.1% fewer cows dropped out than peers of the genotype 97% HL, 3% BW.In herds with tethered housing and year-round exercise of cows, similar data were revealed regarding cows with loose housing, in particular, the age of the first calving, which in cows of the genotype 50% MB, 49% HL, 1% BW was 49 and 23 days less in comparison with peers of the genotype 97 % HL, 3% BW. The lactation curves of cows of two genotypes, which have almost equal milk yield per lactation, differ: in the daughters of Montbéliarde bulls, it is smoother, which favorably affects the stabilization of the reproduction function after calving.