Genomic selection has the theoretical potential to further improve the effectiveness of breeding. Now, company-owned SNP-chips are being utilised in both layer and broiler breeding for this purpose. The focus is on shortening the generation interval, and selecting for specific traits. Testing birds under field conditions will remain necessary for achieving optimal breeding results.
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By Prof. Dr. Rudolf Preisinger, Lohmann Tierzucht, Cuxhaven, Germany
Feeding the world’s growing population with high-quality food is the core aim of agricultural production. In view of the growing world population, this challenge will continuously become larger, especially in the big cities of developing countries where increases of 80 million annually are expected.
The production of eggs in these regions will be of increasing importance as they provide a relatively cheap source of animal protein. In contrast to poultry meat, which is traded between continents in large volumes, eggs are produced typically for consumption within the region, and only in Europe are traded across borders in significant volumes. In addition to conventional selection criteria like egg production, feed conversion and egg quality, traits related to animal welfare have become more important, particularly in Europe and North America. Very costly data recording is required to improve these traits. Novel recording systems have to be developed to test chickens in non-cage environments and husbandry systems accepted by welfare legislation.
Enhancement of progress
Continued genetic progress can be expected within the available gene pool of highly efficient white egg and brown egg lines, based on conventional selection on key traits. However, the laws of diminishing returns also apply in poultry breeding, and efforts to optimize performance testing, selection and reproduction have to be intensified to assure competitive rates of progress. Incorporating additional traits in the complex breeding goal and selection routine will automatically increase the total cost of data recording and lower the rate of progress for all other traits, without generating a measurable return on investment for the breeding company. They are therefore challenged to look for more precise, quicker and/or less expensive methods to evaluate individual and family differences in relevant criteria.
As numerous simulation studies have shown, genomic selection can contribute significantly to the enhancement of breeding progress. In layer breeding, genomic selection has been successfully applied in practice to identify and eliminate the FMO3 gene, which used to cause off-odour in brown shelled eggs.
There is no convincing evidence to date demonstrating that genomic selection can in fact improve all major traits in a complex index at a competitive cost. The following review will address the current status and perspectives of genomic selection in layer breeding in more detail.
