Limousin cattle have been found to have the lowest daily methane emissions, with no impact on performance, initial results from the ICBF, Teagasc and Department of Agriculture Green Breed project reveal.
The five-year €3m study, conducted at the ICBF performance test centre at Tully, Co Kildare, also found that Simmental and Hereford crosses had the highest daily emissions, according to project co-ordinator and Teagasc researcher Professor Donagh Berry.
While noting that the findings are preliminary, Prof Berry described how the methane performance of the Limousin has been a “real curve ball” as they are “heavier and eat more”. “You’d have expected them to have higher emissions,” he said.
The Green Breed study involved 1,500 cattle, “proportionate” to the national cattle population in breeds, crosses and gender with all cattle finished through an indoor system, explained Prof Berry.
Over the 70 days prior to slaughter, the daily methane emissions, feed intake, performance and meat quality of each animal is tested as part of the analysis.
“It’s important that if you’re breeding for lower methane, you don’t want to end up having lower performance. You don’t want to be going backwards on carcase quality,” he said.
Cattle from 320 AI sires were tested as part of the programme, with bulls having up to 12 progeny in the experiment.
Progeny from 57 Limousin bulls, 21 Simmental, 25 Hereford, 47 Angus, 35 Charolais, 56 Holstein, 14 Belgian Blue and smaller numbers of other breeds were included.
At Tully, the average animal was found to have 250g of methane emissions per day or a “quarter of a bag of sugar”, said Prof Berry.
The animal with the lowest emissions released 180g per day, while the animal with the highest emissions released 320g.
At a genetic level, the 20% of the cattle with the lowest daily methane emissions had an average of 220g and the 20% with the highest daily emissions released an average of 280g.
More Limousin-cross cattle were in the lowest-emitting 20% and more Simmental and Hereford cattle were in the highest-emitting 20%, according to the Teagasc researcher. There was a 30% difference in the daily emissions from both these groups.
Holstein-sired cattle were “bang in the middle” while Angus and Charolais were “above average”, with higher daily emissions than the Holstein but lower than the Hereford and Simmental.
Prof Berry said the findings as still had “variability within breed” and importantly, did not take into account the lifetime methane emissions of the cattle, which he said can be affected by age at slaughter.
“They might be burping more [methane] per day but if they’re burping fewer days, their lifetime emissions could be lower,” he argued.
However, the Teagasc researcher suggested that even if an earlier maturing breed such as the Angus is finished earlier, this might not be enough of a saving to gain ground on the Limousin, which was found to emit less methane per day.
Lower carcase weights and units of saleable meat will also affect methane efficiency, he said, arguing that there needs to be a “holistic” approach, finding a balance between lower daily methane traits and earlier finishing.
It’s worth noting that the study did not analyse daily emissions from suckler cows or growing weanlings, for example.
Prof Berry highlighted that the methane-cutting genetic improvements the Green Breed project has uncovered will come at “no cost to the farmer”.
“Breeding is a proven technology. The benefits accumulate over time,” he said.
He explained that with breeding for any trait, such as shorter gestation and calving ability, the general consensus is that a 1% genetic gain can be made per year.
When applying this metric to breeding for lower daily methane emissions, the average daily methane emissions from individual cattle could be cut from 250g to 197g by 2050, he said.
“That’s a drop of 53g of methane per day by 2050, at least a 20% reduction.”
The Green Breed project co-ordinator multiplied this by 1.25m head of cattle slaughtered per year and again by 365 days for the full-year impact.
“By 2050, you’d have over half a million tonnes less of carbon from the national herd each year.
“That’s with no change to farm management. That’s down to the AI companies selecting bulls. The farmer has to do nothing. [They’ll] still be putting the cow in calf,” he said.
Prof Berry also highlighted that progress made on low methane genetics is permanent, whereas a “fix” such as a feed additive has a temporary effect.
“Once you stop feeding the additive, the methane impact is gone,” he said.
However, he suggested that the two approaches can complement each other in working towards the farm sector’s overall climate targets.
The next phase for the Green Breed study is examining the impact of genetics on daily methane emissions of another 1,500 cattle at grass.
Meat Industry Ireland (MII), through Meat Technology Ireland (MTI), is investing resources in this trial,, with five Green Feed machines purchased and on the ground in recent months, at an approximate cost of €625,000 or €125,000 per machine. Ireland has 33 such machines at present, with another two near delivery. Cattle are trained to enter the machine up to four times a day to have their methane emissions measured.
In terms of analysing the role of genetics in methane traits, “beef is out of the traps”, dairy is “still a good bit behind” and the sheep sector is “following suit”, Prof Berry said. To speed up genetic methane improvements, he suggested that there needs to be another 50 Green Feed machines on the ground.
Tully itself has ramped up its own capacity and can now cater for 700 cattle annually, with further analysis to refine the genetic methane trait findings.
Further, large-scale methane measurement across the herd will be required to have the genetic low-emitting traits embedded in Ireland’s national carbon inventories, the Teagasc researcher added.
Minister for Agriculture Charlie McConalogue described the finding that breeding strategies alone could cut methane from the national herd as a “major breakthrough that will be a game changer in our drive to reduce agricultural emissions”.
“The implementation of a low methane emitting breeding programme has significant potential to harness the genetic variation for methane emissions that exists within the national herd. This, in turn, will bring about permanent and cumulative reductions in the methane output of future generations of livestock,” he said.