11 December 2024
Marginal gains achieved from multiple factors, ranging from increasing scanning and rearing percentages to finishing lambs earlier, will combine to both reduce emissions and increase profitability in Welsh sheep flocks.
Many of the key performance indicators (KPIs) that dictate flock productivity are also those that lower carbon dioxide, methane and nitrous oxide emissions, farmers were advised at a recent Farming Connect webinar by sheep vet Fiona Lovatt, of Flock Health Ltd, and Hugh Martineau, Technical Director of Sustainability at the data-driven insights business, Map of Ag.
“Reducing emissions doesn’t sit in isolation of everything else,’’ insisted Mr Martineau, who also runs a sheep flock on his farm in the Brecon Beacons.
“There is a tendency to think of it as a standalone measurement but it’s just another outcome of a productive system or an unproductive system, depending on which way the emissions are.’’
The KPIs he’s set for his own flock are to reduce ewe weight from 75kg to 70kg, increase scanning percentage from 160% to 180% and rearing percentage from 137% to 155%, while speeding up the lamb finishing period to 190 days from 230 days.
But what works for one farm might not work for another, therefore when adapting farming practices, it is important that every farm focusses on changes that are right for their own business.
“Don’t be tempted to compare across lots of other businesses, focus on what’s right for you,’’ said Mr Martineau.
“By all means benchmark against similar systems but there will be different priorities for different farms and different systems, and that needs to be factored into the way you use different carbon measurement tools.’’
Accept that there will be marginal gains across multiple areas, he added - don’t expect a single factor to cut emissions by 20%.
“It is likely that there will be multiple things you can do to tweak the system to drive down emissions towards that theoretical minimum position.
He referenced getting ewes into condition for tupping, good ewe nutrition throughout pregnancy, scanning and rearing percentages and the efficient use of inputs.
“If you are in a situation where you are bringing inputs into the system, make sure they are used efficiently, as I am sure you will, as they tend to be costly,’’ he said.
Twenty-two farmers, members of Farming Connect advanced level sheep discussion groups across Wales, participated in a project overseen by Dr Lovatt. The project involved entering data into the Map of Ag’s Farm Metrics Greenhouse Gas (GHG) Emissions ‘What if’ tool. Changing any number of parameters allowed each farm to explore their own flocks and farming practices and to consider what they could do to make a difference to emission intensities.
Among the participants were Peter and Anne Cattell, of Coed Derw, Llandyrnog, who run a flock of 150 Lleyn ewes and 50 followers on 45 acres. In 2022/23 the flock achieved a scanning percentage of 177 with 2.7% empty ewes and a rearing rate of 170%.
Coed Derw is run as a high input - high output system. Pre-lambing, the ewes are fed a total mixed ration (TMR) of high quality, home-grown silage, soybean, sugar beet and molasses while post-lambing concentrates are introduced. Lambs are creep fed from two to three weeks of age until sold at four to five months.
Although the Cattell’s have the highest feed use across all 22 flocks, the highest rearing percentage and shortest number of days on farm for finished lambs, the emissions calculated for their flock sit at an average level within the group.
Having tried various scenarios within the model, Dr. Lovatt advised changing to sustainable sources of bought in feed, designated in the tool as ‘no land use change’, across all their feed inputs to reduce the flock’s emissions intensity (EI) from 27.18 kg CO2-eq per kg of deadweight (dwt) to 25.73kg CO2-eq/kg dwt.
In reference to ‘no land use change’, Mr Martineau said land use change emissions are the emissions attributed to feed as a result of changes in land use on the area of land that the feed has been grown.
Emissions calculators must account for areas of land that have been deforested within the last 20 years to grow crops for feed or for other uses.
“The emissions created by deforestation are divided by the crop output and then allocated to the lamb product emissions,’’ Martineau explained.
Dafydd Owen, who is share farming at Coed Coch Farms, Abergele, where he runs a flock of 2,000 Romney ewes on an all-grazing system, also participated in the project.
The ‘What if’ tool showed that the flock’s emissions intensity for 2023/24 was 28kg CO2-eq/kg dwt.
Increasing scanning percentage to 182% and rearing percentage to 150% while reducing ewe mortality to 3% could reduce that figure to 25.2kg, the modelling exercise showed.
But while this may be an aspiration, Mr Owen said it is possibly unappealing in his system as it would result in too many triplets that require higher inputs, highlighting the message that any changes farmers were to introduce must work for their own individual system.