Genomic Analysis of Latvian Brown Old Type and Latvian Blue Local Dairy Cattle Breeds Using SNP Data

Abstract

In Latvia, there is only a small number of the native dairy cattle breeds: Latvian Brown old type and Latvian Blue. The protection and breeding of these breeds, which are genetically adapted to traditional production systems, are very important. Using genome-wide SNP data, breed diversity and genetic variation were analysed. Recent and ancient inbreeding in the BV and LZ populations were estimated based on homozygosity runs. Regardless of the lower number of bulls, the Latvian Blue breed had a much higher level of inbreeding than the Latvian Brown old type. The relationship between genomic inbreeding and milk productivity and a negative phenotypic correlation between genomic inbreeding and milk yield for both breeds was observed. The Latvian local cow breeds are not characterised by high milk yields, but they do have a high dry milk matter content. Keywords: SNP data, inbreeding, heterozygosity, ROH, milk yield