The distribution of lethal Holstein haplotypes affecting female fertility among the Russian Black-and-White cattle

Background: Many genetic defects have been discovered and proved to be associated with the decrease of female fertility of dairy cattle. These defects are now selected against in many countries. The occurrence of these defects among the Russian dairy cattle has never been extensively screened before. In this study, we will investigate the occurrence of 10 lethal recessive Holstein haplotypes HH0 (BY), HH1, HH2, HH3, HH4, HH5, HCD, HHC (CVM), HHB (BLAD) and HHD (DUMPS) among the Russian Black-White cattle, and we will determine the carrier frequency and the frequency of the mutant alleles for these haplotypes.  \nMaterials and Methods: 1991 animals (1500 bulls and 491 cows) of the Russian Black-and-White cattle were included in the study. Two methods were used for identification of carriers of mutations. The first one is genotyping the animals using the bovine DNA chips that contain the mutations and the second one is the polymerase Chain Reaction (PCR). \nResults: The results clearly showed the presence of these defects among the Russian Black-and-White animals. The occurrence was relatively high for some defects such as BY, HCD, HH1 and HH3 with a carrier frequency of 4.11, 5.66, 2.96 and 2.88%, respectively. No carriers were detected for DUMPS. \nConclusions: This work represented an important attempt for extensively screening the occurrence of various genetic defects among the Russian dairy cattle. This has a significant importance in breeding programs. It helps breeders to make an appropriate mating decision by mating only carriers to non-carriers. Such management leads to avoid the economic losses and to decrease the frequency of the mutant alleles in the cattle population.