Bullish on a Better Breed

This week I’m feeling bullish.

Because I think we’re closing in on a big win, and it’s all to do with cattle – bulls in particular.

Cattle are like the original gangsters of agricultural emissions: the single largest emitters from the sector, with their stomachs acting like 1.5 billion independent methane factories. And as we all know, methane is a much more potent greenhouse gas than CO2 in the near term.

But as it turns out, emissions can vary widely between animals in the same herd. We know this thanks, in part, to what are endearingly referred to as fart tunnels. Cattle feed inside these large, sealable tarpaulin tents, enabling scientists to measure the methane they emit and how it changes according to what they eat. It turns out some animals produce a massive 30% less methane than others despite the same feed, feeding regime, environmental stressors, and everything else. 

Holy cow!

These studies strongly suggest that some cattle are genetically predisposed to generate lower emissions than others. But breeding low-methane cattle would be complicated and take years – decades even, right?

Right?

Wrong. It’s not actually that hard, or slow. And the key is something called genomic prediction. A new portfolio of Earth Fund grants is betting big on this, supporting the development of a genomic predictor of low methane for all major beef and dairy breeds. 

Let me explain how.

If you’re a rancher, and you want to artificially inseminate your favorite cow, you essentially get the equivalent of a shopping catalogue for bulls, with a long list of indicators that describe each bull’s redeeming features: size, shape, quality, and so on. Many or most of those indicators are derived from genomic prediction – by studying the genes of the bull, we can know what quality the milk might be in the resulting offspring, or the animal’s likely weight, and so on. These indicators combine into a final score, sometimes called a breeding value. Ranchers use this score to select the bull they want to father their next generation of calves, The higher the score, the better the bull.

Now, if we can determine the genes responsible for low-methane production, a genomic predictor for it can be built into the breeding value. The lower the methane level, the higher the score. Then, if they want to, ranchers can pick the bull that promises low-methane offspring without compromising other breeding characteristics. 

When you consider that the global herd of cattle is replaced roughly every three-to-seven years, you start to see how quickly low-methane cattle could become established as the norm when embedded in the selection process.

The new Earth Fund grants will support a global effort involving dozens of universities, breeding organizations, and government agencies across multiple continents to move the dial on low-methane cattle. The Global Methane Hub is co-funding this with us, and Wageningen University & Research have taken the lead role in what we are calling the Global Methane Genetics Initiative. 

The plan is to sample over 100,000 animals across different breeds and in different production environments. We’ll measure their emissions, their genetics and the microbiome in their rumen. All the data will be made publicly available for anyone to use. 

The data can then be used to predict the likely methane emissions of any animal from those breeds. This will allow breeders to select for low methane and provide transparency to ranchers about the methane performance of the genetic stock they are buying.

Simple as that. 

The approach is elegant and systematic. It probably means a few more fart tunnels around the world, as well as other approaches for measuring emissions. But we believe it goes to the heart – or rather the stomach – of tackling emissions from cattle. 

Bull’s eye, you might say.