The method of calculating stocking rates in agri environment schemes was called into question during an online event on Tuesday.
Dr Mariecia Fraser from Aberystwyth University was critical of the livestock unit (LU) system which is used to compare stocking rates across different types of livestock. For example, a suckler cow is 0.8 LU and a breeding ewe is 0.15 LU.
Fraser pointed out that the system does not consider other key factors that are required for effective grassland and habitat management, such as the duration of grazing and the type of livestock used.
“The livestock unit system is an incredibly blunt tool for the type of job that it’s trying to do,” she said during the British Society of Animal Science event.
Livestock units are used in NI for calculating stocking rates in the current Environmental Farming Scheme and were part of the former Areas of Natural Constraint scheme.
During her presentation, Fraser said that type of livestock on uplands is “hugely important” for maintaining biodiversity in semi-natural grasslands.
She acknowledged that there is still “ongoing debate” about how to classify the grazing behaviour of different livestock.
However, sheep are seen as highly selective grazers and over-stocking uplands with sheep can reduce sward biodiversity.
“Introducing less selective grazers, such as cattle and ponies, can reverse some of the damage caused by sheep only grazing because they are prepared to take some of the lower digestibility material that sheep avoid and their physical presence helps to open up dense swards,” Fraser said.
“If we have the system right, we can get production as well as environmental benefits,” she concluded.