Genes in context

Oliver C. Jann, PhD

Breeding goals of livestock are normally determined by the desire of producers to improve economically important production traits like e.g. milk yield, daily gain or carcass quality. The main mechanism to pursue these targets is selection of superior animals which are expected to inherit favorable gene combinations.

However, economic success is not determined by production traits alone. And genes do not act as independent factors. Genes must be seen in a wider context - with each other as also with the environment they interact.

As a consequence, genetic improvement requires an integrated approach:

Firstly, production takes place in different environments. Generally speaking, genetics must be developed and tested under the same conditions as the production takes place. The import of high yielding genetics from other climates or selection of elite animals under artificially optimized conditions might be fashionable, but contra productive from an integrated genetic perspective. 

Secondly, sustainable thinking forces us to develop new breeding goals. One-sided selection on production traits does neither help with product quality nor with the adaptation to different environments. New breeding goals, including resistance and quality traits, must be developed and integrated into environment specific breeding programs.

Thirdly: it is true, that the existing methods for performance recording and subsequent estimation of breeding values (EBVs) are rather sophisticated. However, EBVs must be assessed with caution, especially if based on performance records from different environments. In addition, the current focus on EBVs should not distract the attention from visually assessed functional traits like body conformation or soundness. In the last years the scientific focus moved on to develop new genomic tools based on DNA analysis. Recent scientific advances in this area are very promising. An integration of classical and molecular breeding methods is desirable.

And finally, breeders should make use of the complete available genetic diversity, to enjoy best possible gene combinations and hybrid vigour. Many rare or low producing breeds carry a wealth of most interesting genes affecting quality and resistance traits. Crossbreeding with genetically distant breeds maximizes heterozygosity and scientific findings of the genetic relationships among breeds provides most valuable information for an optimized breeding program.

Combing scientific findings and synchronizing them with the goal of productivity should lead to integrated systems which can be applied in practical breeding. This we call: Integrated Genetics.