Abstract

A profitable dairy cow is a popular goal in the dairy industry. Fortunately, several strategies can lead to a profitable cow (high lactation production, low costs, elite lifetime production, outstanding unique genetics, great efficiency of production, or disease resistance). The focus of this project was to identify unique genetics of Holstein cows with elite lifetime production (> 68,039 kg of lifetime milk production and classified very good or excellent). The final sample contained 814 elite cows and 803 control cows with genomes tested on 50K chips. A haplotype trend regression was conducted on the differences between the two groups and five sets of haplotypes were identified, one each on chromosomes 6, 13, 23, 24 and 26. Each set of haplotypes contained from three to five overlapping 5-SNP haplotypes. In addition, clusters of runs of homozygosity (ROH) were evaluated. One cluster of approximately 28 SNP from chromosome 22 was found in 83 elite cows but not in any control cows. The first marker of this unique cluster was ARS-BFGL-NGS-39645. Evaluation of the pedigrees of the elite and control cows revealed more sires and maternal grandsires represented in the pedigrees of the elite than control cows. This pedigree diversity continued within the 83 elite cows, with the unique cluster of ROH, because they were daughters of 61 different sires. Breeding a more profitable cow may be a single goal, but the paths to success are varied, partly as a result of the diversity among elite cows. Keywords: lifetime milk production, haplotypes, runs of homozygosity, dairy cattle, Holstein

Roger Shanks

Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume Electronic Poster Session - Biology - Disease Resistance 1, , 590, 2018
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