Characteristics of the chromosome set of Holstein cows with reproductive disorders in the North-Caucasian cattle population

Abstract

Increase in the degree of consanguinity of Holstein breed identified to the best-cultivated dairy breeds is one of the major ways to improve the genotypes of the dairy cattle in many countries all over the world. The widespread biotechnology and large-scale selection adoption reduced the range of the used bull sires in dairy stockbreeding, which resulted in the occurrence of different abnormalities associated with the inheritance caused by gene mutations and chromosomal disorders in the newborn calves. Since the main part of such abnormalities has a recessive inheritance pattern, they represent a hidden genetic load, which is not always expressed in a phenotype. In recent years, the cytogenetic and karyotyping approaches have become more widespread and are required for both the detailed theoretical prerequisites and the applied problem solutions to prevent losses in agricultural production. The results of the cytogenetic analysis of the North- Caucasian population of Holstein cows having problems in reproduction have been reported. The aberrant cells are detected (frequency of occurrence is 5.35%); the number of aberrations per analyzed cell (0.05/1.0) is determined; the absence of the reciprocal translocations in a karyotype in the analyzed livestock is revealed. The genealogical interrelations of ancestors of the lines of Montivik-Chifteyn no. 95679 and Reflekshn- Sovering no. 198998 bull sires with the values for stillbirth incidence among their progeny have been traced.