Genomic Selection to enhance Performance and Health in Danish Sport Horses  

Background

The breeding evaluation of most large riding horse breeds in Europe today is conducted using the Best Linear Unbiased Prediction (BLUP) method. The method uses all known pedigree relationships among horses and is based on phenotypic results that the horses have accomplished – for instance in young horse tests and in competitions. Furthermore, it corrects for environmental effects that are not inherited such as rider, sex and age. This method has proven very successful in finding the part of a performance trait that is due to genetics, and thus to find the best horses to use in breeding. However, since the method is based on phenotypic results, often recorded quite late in life of each horse, stallions generally are old before having enough tested offspring to obtain a high accuracy breeding value. This results in long generation intervals. Genetic markers (i.e. SNPs) is an additional source of information that could be incorporated into the breeding evaluation to enable accurate early selection of horses. This method is called “Genomic selection”.

Potential and obstacles in genomic horse breeding

Genomic selection holds great potential to improve breeding of sport horses in similar ways as it has recently revolutionized breeding of many animal and plant species. It can deliver accurate breeding values for newborn foals including those of foreign origin for any heritable trait being measured systematically. This allows for greatly reducing generation intervals.

However, it takes a large number of horses with both genotype and phenotype data in a so called “reference population” to establish accurate genomic prediction equations. Provided a large reference population and some initial research efforts, the breeder can obtain an accurate prediction of the foal’s potential from a genotype which can easily be generated from a blood or tissue sample for about 130 € per horse. In the future the price is expected to decrease further as the technology becomes more widely used.

The GenHors project

In the present three year R&D project that started in October 2013, approx. 500 of the most informative Danish Warmblood stallions will be genotyped, for 70 000 gene (SNP) markers, with focus on traits for performance and health. The aim of the project is to include these SNP markers in the regular BLUP evaluation simultaneously with the phenotypic information of the whole Danish Warmblood population, enabling all information to be considered simultaneously. If successful, this could markedly increase the prerequisites of breeding high performance horses of good health.   

The project is financed by The Danish National Advanced Technology Foundation, University of Copenhagen, and the Danish Warmblood Association through Asta og Jul. P. Justesens Foundation.