Holstein-Friesian Relationships and the Impact on the Accuracy of an Across-Breed Evaluation

Abstract Text: Genomic evaluations are limited in their success for some cattle breeds due to the small size of reference populations. The objectives of this study are to investigate the level of relationships between animals in two breeds and the impact of the relationship on the accuracy of an across-breed genomic evaluation. The dataset consisted of 4,726 genotyped Holstein and Friesian individuals used in the UK, split into reference and validation populations based on year of birth. Principal components analysis based on the numerator relationship matrix (A) and genomic relationship matrix (G) was used to visualise relationships between breeds, and genomic predictions for yield traits were calculated. Results suggested that accuracies increase as the relationship between breeds increases, and that British Friesians seem to be more closely related to Holstein cattle than to Irish Friesians. 

Keywords:

Genomic evaluation

Multi-breed

Principal component analysis