The power of genetics

Addressing a captive audience of several hundred at the Department of Agriculture, Food and the Marine’s (DAFM’s) conference, Agriculture and Climate Change – Science into Action, Donagh outlined how animal breeding is being brought to bear on the issue of carbon reduction in the Irish livestock herd: “Breeding is cumulative and permanent, very much mirroring what Albert Einstein said about compound interest being the eighth wonder of the world; the benefits build over time.”
Today’s herd is the result of genetic improvement over decades and longer, he said. “The beauty of genetic improvement is that there is no need to change farm-management practices. With artificial insemination for instance, the practice is the same, whether you use a mediocre straw or one that can enhance future genetics in the herd. There are no or negligible additional costs involved. The farmer is already breeding year on year and the results from improving genetics are sustainable.”

The carbon index

The geneticist concentrated his main theme around the impacts on carbon and methane reduction from targeted breeding. He allied his breeding theme with the associated benefits of reducing the age of slaughter in beef animals: “We are the first country to include carbon in our beef and dairy breeding indexes. Currently we don’t directly account for the variability in methane production by our animals. All our breeding improvements have been positive in improving profitability. Dairy improvements are further along as the EBI started earlier. We have shifted the mean of the dairy population by three standard deviations.” Using a comparison with human IQ, Donagh compared the dairy improvements to lifting the human average intelligence figures so that half of the population would be regarded as gifted. “It’s a phenomenal improvement over a relatively short timeframe.”

He pointed out that, with advanced breeding practices, it has been possible to deliver improvements across a range of traits, without compromising fertility, for instance, in favour of yield. “With beef breeding there is a similarly positive outcome from breeding selectively for various traits. The targets must be important, they must be measurable, and they must demonstrate genetic variability.”

Genetic variability for methane production?

A central question answered by Donagh in his address at the climate conference was whether there is genetic variability for methane production. Using a graph to illustrate his point, Donagh showed that the average daily methane production by an animal is 240g. The distribution is large with some producing almost 400g and at the lower end some producing 100g per day. His research asked how much of that spread is genetic and found that about 40 per cent in beef is attributable to breeding while in sheep the figure is 30 per cent. Data is still being collected and analysed to determine the percentage of dairy methane production related to genetics, he said. The research into methane emission genetic disposition provided clear results: “Under similar management practices, around 40 per cent of the variability on methane production in beef cattle is due to their genetic differences. Those differences come without any compromise in their performance in critical factors such as slaughter age, weights or conformation. This data allowed us to develop the first national genetic evaluation for methane in cattle in the world. We have also developed genetic evaluations for sheep in respect of methane production. With widely adopted genetic breeding for methane reduction, the cumulative effects over the cattle population can be very significant.”

From concepts to conclusions

Validation is, of course, necessary to provide objective proof of the practical application of the concepts Donagh outlined. This is happening, as he explained: “In breeding, we are trying to predict the future outcomes based on current data and knowledge. The outcomes of our validation exercises show that those animals predicted to be low methane emitters, turned out to be, in practice, low emitters. This is where science and theory are shown to be true in the physical outcomes. The reason is straightforward. Forty per cent of the emission differences is due to variations in genetics.”
Donagh explained the compromises necessary to safeguard economic sustainability at the same time as genetic progress is made in environmental sustainability: “We select within an index taking all the critical traits, including methane suppression as well as performance criteria into account. An extreme improvement in methane reduction accompanied by a reduction in economic performance would not be a successful outcome. By balancing the traits, we still have a significant outcome for methane reduction. In practice the animals must be low emitters per day as well as providing heavier carcasses.”

The killing point

Age of slaughter was another key aspect of Donagh’s presentation: “Thirty per cent of the difference in age of slaughter can be attributed to genetics. We are the only country in the world that is actively selecting for reduced age of slaughter. We must think long term. While MACC and other known technologies may be fully adopted by 2030, the benefits of breeding have longer-term application and benefits, running all the way to 2050 in terms of the methane reduction targets set for the longer term.
“In animal breeding, we tend to see a one per cent improvement per year. That’s the norm in well-developed breeding programmes. Just to be conservative, we will halve that figure. If we were to model a one per cent annual improvement per year, in reducing age of slaughter or reduced methane emissions, we would achieve around an 11 per cent reduction, equivalent to a three-month improvement in age of slaughter. The broader benefits include the fact that we not only improve methane emission percentages or carcass weight. We improve methane per day and age of slaughter, both of which will improve at a rate of 0.5 per cent per year, at those conservative estimates. In practical terms, that will deliver a reduction to a little above 90g of methane per day from the cumulative effects of breeding for methane reduction as well as reduced slaughter age.”

A definitive breeding pathway

The Teagasc genetic scientist was adamant of the benefits of breeding: “I don’t use the words ‘could’ or ‘might’. ‘Will’ and ‘can’ are the appropriate outcome descriptions from selective breeding based on genetic traits. It has been proven over centuries across a range of positive traits and we have now shown its applicability in delivering methane emission reductions. A primary benefit from genetic improvements is that it is capable of mass adoption. There are no huge changes necessary in farm practice or management to achieve positive outcomes.”