Novel real-time PCR methods for bovine haplotypes HH3, HH6, HH7 diagnosis

Dairy cattle breeding is aimed at improving the productivity, mainly through the use of a limited number of breeding bulls. As a result, an increase in inbreeding is observed causing accumulation of heterozygotes-carriers of recessive lethal mutations. A rise in the number of carriers reduces the profitability of dairy farms, since the frequency of embryonic and post-embryonic mortality increases, and the fertility of cows decreases. This paper presents the results of the development of test systems for rapid and inexpensive diagnostics of genetically determined cattle diseases that are significant for animal husbandry, namely for Holstein haplotypes 3, 6 and 7. The diagnostic technology is real-time PCR using TaqMan probes. Carriers of the Holstein haplotype 3 were not found in any of the studied populations. The carrier frequencies for HH6 and HH7 were 0.95 and 1.92%, respectively. Carrier frequencies are consistent with the results of studies worldwide, however, it is worth noting that only few large-scale screening studies have been carried out, since causative loci have been mapped relatively recently.