A Genomic Information Nucleus to Accelerate Rates of Genetic Improvement in Sheep

Any breeding program has to find the right balance between investment in information and obtained rates of genetic improvement in the wider population. It was already pointed out by Robertson and Rendel (1950) that "the apparent lack of connection between an animals' breeding value and its phenotype led many to advocate more complicated methods for judging genotype". This led to their proposal of a progeny testing scheme for dairy, as it is particularly hard to select dairy bulls directly based on phenotype. The use of artificial insemination (AI) along with the fact that the main traits are sex limited has led to progeny testing becoming prevalent in dairy breeding systems. It is interesting to note that with the advent of genomic selection tools, it was quickly pointed out that these dairy breeding programs could also greatly benefit from this new technology (Schaeffer, 2006). Indeed, whether testing progeny or genomes, these are examples of 'more complicated methods' to increase selection efficiency, and breeding programs have been and will have to be designed to exploit such tools optimally.