70% of the emissions associated with a litre of milk “are in the hands of the farmer to reduce” – with a reduction of up to 20% over a five-year period “achievable” across four key areas, according to Alltech.
At the online Alltech Ireland Environment Forum, presented by the animal nutrition giant last Wednesday (April 28), Emma Swan, InTouch feeding specialist with Alltech, outlined in a presentation how Irish dairy can significantly reduce its carbon footprint.
Emissions
“We in Alltech believe that, as an industry, we can achieve a reduction of 20% in our carbon footprint of milk solids produced by 2026,” Swan said.
“70% of emissions from a litre of milk actually come from inside the farmgate – and are in the hands of the farmer to reduce.”
This, she said, can be done through four key areas: grassland management; herd performance; dairy farm inputs; and genetics.
Grassland management
Starting with grassland management, Swan noted that “continued education” is key to driving best practice uptake in this area.
“It’s all about getting the basics right. We need to measure, improve soil fertility, have a reseed programme, and in terms of nitrogen use, look at including clover in our grassland to reduce our nitrogen fertiliser requirement.
Pointing to the benefits of doing this right, the specialist said: “From 2019 to 2020, farmers on the InTouch system that measured grass using Pasturebase grew an extra 1.5t/ha of grass.
“They produced an extra 20kg of milk solids without feeding any extra concentrate feed.”
Measuring the emissions production of various grass covers, Swan continued, gave some interesting results:
“We have tested and compared emissions from low covers averaging 600kg DM/ha, optimal covers averaging 1,500kg DM/ha and high covers averaging 1,700kg DM/ha.
“What we found is that the optimal covers release just 530g CO2 emissions per kg of dry matter (DM).
“This optimal cover produced the least emissions as it was the most digestible for the cow compared to the low and the high cover,” she said.
Herd performance
Moving on to herd performance, it was noted that the key to performance in any herd is managing body condition score (BCS). “UCD and Teagasc research have highlighted that cows in correct body condition score go in-calf quicker, produce more milk and have increased longevity in the herd,” Swan said.
Continuing to the related point of nutrition, the Alltech specialist pointed to “efficiently feeding cows for performing at the right time” to prevent a sudden drop in milk solids during peak lactation.
In a study comparing 2019 and 2020 InTouch data, the firm found “this extra milk production was worth an extra 47kg milk solids per cow, equivalent to €21,000 in milk sales in 2020”.
“What this really came down to was feed efficiency, as there was no extra concentrate feeds per cow in 2020,” she added.
“Assessing the herd performance of over 100 dairy farmers in Ireland over the years using InTouch technology, we have found that cows have increased performance by 34kg of milk solids per lactation through improved efficiency.
“An improvement in feed efficiency means that more nutrients are utilised for production by the cow with less emissions being lost to the environment.” This, Swan added, involved supplementation of minerals to “ensure requirements are met for optimal performance”.
Farm inputs
Turning next to management of farm inputs – and focusing on feed and fertiliser – Swan highlighted the ongoing work being done to monitor and reduce the global warming potential (GWP) of feed rations through reformulation. Noting one feed that Alltech reformulated for a commercial Irish mill, she claimed:
“We reduced the GWP by 51% while also reducing the cost of the feed by €2/t. When we used the environmental assessment tool based on the carbon footprint of our feed, we commonly see a reduction of between 20 and 30% in GWP.
On fertiliser, the InTouch specialist said: “If we switch from urea to protected urea, we can reduce ammonia emissions by almost 80%, which would have a direct impact on the reduction of our nitrous oxide emissions.”
In terms of slurry management, she continued, low emission slurry spreading reduces ammonia emissions by 50% – but storage also needs to be looked at.
“One exciting technology that we are currently investigating is the use of a slurry additive.
“Through our previous trial work on this, we have found a reduction of 44% less ammonia emissions by using this slurry additive.
“This means we will have more nitrogen in the slurry which can be applied to grass and utilised for growth,” she added.
Genetics
Finally, Swan highlighted the environmental impact of improved genetics in the dairy herd, highlighting: “A study carried out on the next generation herd in Teagasc Moorepark shows that herds of a high EBI had a 10% reduced carbon footprint per unit of milk produced.
“This reduction in carbon footprint was driven by improved efficiency through better fertiliser, health and milk solids production.
“If we focus on all of these areas, we certainly think it is achievable to hit our target of a 20% reduction in the carbon footprint of milk by 2026,” the specialist concluded.