Skip to main content
ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Genomics and Improvement Laboratory » Research » Publications at this Location » Publication #314788
Title: Genomic evaluation, breed identification, and population structure of North American, English and Island Guernsey dairy cattle

Author
item Cooper, Tabatha
item EAGLEN, SOPHIE - University Of Edinburgh
item Wiggans, George
item JENKO, JANEZ - University Of Edinburgh
item HUSON, HEATHER - Cornell University
item MORRICE, DAVID - University Of Edinburgh
item BICHARD, MAURICE - Collaborator
item LUFF, WILLIAM - Collaborator
item WOOLLIAMS, JOHN - University Of Edinburgh

Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 3/19/2015
Publication Date: 7/12/2015
Citation: Cooper, T.A., Eaglen, S.A., Wiggans, G.R., Jenko, J., Huson, H., Morrice, D., Bichard, M., Luff, W.G., Woolliams, J. 2015. Genomic evaluation, breed identification, and population structure of North American, English and Island Guernsey dairy cattle. Journal of Dairy Science. 98(Suppl. 2)/Journal of Animal Science 93(Suppl. 3):345–346(abstr. T88).

Interpretive Summary:

Technical Abstract: Genomic evaluations of dairy cattle in the United States have been available for Brown Swiss, Holsteins, and Jerseys since 2009 and for Ayrshires since 2013. As of February 2015, 2,281 Guernsey bulls and cows had genotypes from collaboration between the United States, Canada, England, and the island of Guernsey; contributions from England and the island of Guernsey were made possible by the European Commission’s Gene2Farm project. Of those genotypes, 388 were from bulls and 498 from cows with traditional evaluations. Genomic evaluations were calculated with the same procedures used for other US genomic evaluations. Evaluation accuracy was assessed using 4-fold cross-validation, where 25% of bulls were designated as the validation set and all cows and the remaining bulls were the training set. Cross-validation was repeated 10-fold, and gains in reliability over parent average were averaged. Twenty-two traits were analyzed: 5 yield traits, 3 functional traits, and 14 conformation traits. Across all traits, mean gain in reliability over parent average was 14.4 percentage points; corresponding gains for Ayrshires, Brown Swiss, Holsteins, and Jerseys were 9, 24, 40, and 31 percentage points, respectively. For Guernseys, the highest gains were for strength (25.1), rump width (24.8), and fat percentage (24.2), and the lowest gains were for somatic cell score (0.9), protein yield (1.0), and fat yield (1.6). Twenty-one single nucleotide polymorphisms were useful for Guernsey breed determination and are used in routine genotype quality control to confirm breed and identify crossbreds. An admixture study using principal component analysis was conducted to determine genetic differences among Guernsey populations in England, the island of Guernsey, the United States, and Canada. No haplotypes that affect fertility were identified from the current data set; however, monthly assessments are conducted. The results of this study are expected to lead to routine genomic evaluation of Guernseys.