The Science of Genomics - Animal Agriculture
1. Why genetics is important?
Genetics is the study of inheritance and in animal breeding, we use what we know about genetics to
improve the merit of our cattle. If the genetic merit of a herd is not high, producers will incur a lot of
unnecessary costs (e.g. extra feed, replacement costs, and veterinary costs). In other words, genetics
creates the potential for what an animal can be, management delivers on that potential. If the potential
is not there, either very expensive management or no amount of management can deliver the animal
you want. Genetic improvement provides a way for cattle producers to enhance the performance of
their herds. The investment in genetic improvement is important and worthwhile due to it being
cumulative (improvements made in one generation are added to those made in previous generations)
and permanent (the performance of an animal is influenced for life and the superior genetics can
remain in the selection population).
2. Tools for genetic improvement
- Data recording
Simply put you have to measure what you want to improve. Or, in the modern era of genomics,
capitalise on those measurements and research and that have gone into the development of tools
developed for DNA assisted selection (genomic selection). There are many software available for
the capture of phenotypic data and its subsequent analysis. The analysis of this data for genetic
merit usually requires a third party.
- Parentage and pedigree recording
This also ties into the aforementioned data recording. To know what sire does what and/or to build
a pedigree of your herd or population, parentage need to be known on animals of interest. The
investment in parentage verification has been shown to have a huge benefit when choosing or
culling breeding stock and is a necessity when doing a genetic evaluation.
- Genetic merit calculations (EBVs and EPDs)
Choosing animals based on how they look comes with all types of pitfalls. One animal may look
better than the other for a whole host of reasons (better management from one farm to the next,
different parity of dam, different age at time of selection, mother had more milk etc.) which clouds
the judgment of an individual animal's true genetic merit. To this end, expected breeding values
(EBVs) or expected progeny differences (EPDs) are genetic merit scores which are derived by pulling
apart the environmental and genetic effects. Ranking animals based on their genetic merit is best
practice when choosing the best breeding animals.
3. Another new tool for genetic improvement - Genomics
Utilizing genomics will increase the accuracy of genetic evaluations of cattle. Where genetic evaluation is
presently performed using pedigree analysis, genomics will enhance this evaluation. Where genetic evaluation
of an animal is absent altogether, it now enables genetic merit scores to be delivered on a cohort of selection
candidates. The accuracy from genomic means greater confidence that the estimated breeding values will be
reflected in their progenies performance which results in accelerated genetic gain.