Title: Genomic evaluation and identification of haplotype affecting fertility for Ayrshire dairy cattle Authors
Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: February 23, 2013
Publication Date: July 8, 2013
Citation: Cooper, T.A., Wiggans, G.R., Null, D.J., Hutchison, J.L. 2013. Genomic evaluation and identification of haplotype affecting fertility for Ayrshire dairy cattle. Journal of Dairy Science. 96(E-Suppl. 1):74 (abstr. T206). Technical Abstract: Genomic evaluation of dairy cattle in the US has been available for Holstein, Jersey and Brown Swiss since 2009. As of February 2013, there were 1,100 genotyped Ayrshires in the North American database including 646 bulls with traditional evaluations allowing for the evaluation of this breed. Gains in reliability due to genomics were determined by comparing parent averages and genomic evaluations from August 2009 to February 2012 daughter performance for bulls born on or after January 1, 2000 who received a traditional evaluation by February 2013. The number of bulls tested ranged between 147 and 180 bulls by trait. The average gain in reliability over parent average for all traits was 8.2. The highest gains were found in milk yield (16.6), protein yield (16.9) and stature (16.2). These evaluations were calculated based on the North American population and may not be suitable to all red dairy cattle because linkage disequilibrium probably differs by population. There are 12 SNP in Ayrshire that can be used for breed determination because they are nearly monomorphic (>90%) in Ayrshire and have fewer than 30% of animals homozygous for that allele in Holstein, Jersey and Brown Swiss. There are fewer breed determining SNP in Ayrshire than in Holstein, Jersey and Brown Swiss, mostly due to the similarity of Ayrshire and Holstein. A haplotype effecting fertility was found located on chromosome 17. This haplotype first originated in the genotyped population with SELWOOD BETTY'S COMMANDER (b. 1953). The carrier frequency for genotyped Ayrshires is 23.2%. Sire conception rate was 3.0% lower for carriers of the haplotype as determined by 483 carrier by maternal grandsire carrier matings. Genomic evaluations of Ayrshire provide improved prediction over parent average, raising reliability by 8.2 over all traits.