Genetic tools aid pig improvement

Tim Rymer, chairman of pig breeding company JSR, and Dr Grant Walling, JSR director of science and technology, share their thoughts on how pig genetics has evolved and where it is heading next.

Pig genetics has been transformed over the past 30 years with the drive for faster growing, leaner pigs as well as an increase in demand for pigs suited to outdoor system. But what does the future hold?

1. How has pig genetics changed over the past decade?

Health, professionalisation of farming businesses and a much greater emphasis on the profitability of pig production businesses have been the biggest contributor to genetic change in the UK over the past decade.

Genetic progress is measured in pounds and pence to the farmer not on the individual performance or looks of a single animal. Pig genetics has also had to deliver even more tools to enable our customers to achieve their goals.

For some, this means using dam line semen and structured programmes to create their own parent sows. For others, it means using different sire lines to maximise hybrid vigour and growth rates to allow them to access alternative markets.

2. What is your biggest technological advance of the last 20-30 years?

Without doubt the greatest technological advance in pig genetics was the implementation of Best Linear Unbiased Prediction to create breeding values for individual animals.

It was only in the 1980s that this became possible, not because the science was too complex earlier, but because the computing power to run the calculations on complex pedigrees wasn’t previously available.

Now we solve more than 7.5 million equations a week with relative ease to generate the statistics on every animal in our breeding programme. It is difficult to think what the industry would look like without this tool to improve low heritability traits such as litter size.

3. How important is pig genetics in helping meet future demands?

The three main benefits for genetic improvement are: i) any change is permanent so improvements made now are not lost in future generations; ii) any change is cumulative so future genetic improvement builds on existing improvement; and iii) Sustainability – the potential to make genetic improvement in the future should not be limited by the genetic improvement we are making now.

Very few other technologies in livestock production meet these three criteria of permanence, cumulativeness and sustainability.

For example, vaccines need to be given to each generation of animals. This is why genetics is by far the best tool to meet future demand.

4. Where next for pig genetics?

It is always difficult to predict the future. Experience shows predictions have a habit of coming back to ridicule you.

We are certainly seeing a greater role for genetics to emphasise the meat-eating quality of pork. Other areas of interest are around the genetics of immune response and how animals cope with disease challenge.

With greater importance being placed on antibiotic use it is likely that genetics will need to deliver an animal that thrives under lower levels of medication on pig units.

Social behaviour of pigs has a significant impact on their performance and some of the work now illustrates genetics can influence behaviour and as knowledge accumulates in this area it will likely become a more scrutinised trait.

Finally, we are watching with interest the developments at Roslin on genome editing – not a technology that has won over the consumer – but may potentially provide answers to questions that we cannot address with conventional genetics.

5. How does pig genetics in the UK compare with abroad?

The UK is unique in having about 40% of its breeding herd outdoors and climatic and geographical issues mean it is unlikely that this will ever be introduced elsewhere in the world.

There is clearly a need for a different sow outdoors but the challenge of seasonal infertility is primarily a UK problem and it has to be addressed by the UK industry since a solution will not be generated elsewhere.

The overseas market generally has more vertical integration, a greater cooperative structure (especially at the farming level), heavier carcass weights, higher emphasis on throughput and a lower emphasis on welfare and meat eating quality.

Overall however the same issues affect pig producers and hence set the same demands for pig genetics globally.

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