A PRECISION approach to worming sheep could reduce wormer use in UK sheep flocks by 40%, improving lamb performance, reducing greenhouse gas emissions on-farm and slowing the rate of drug resistance – according to scientists at the Moredun Research Institute.

There are 33.7 million sheep and lambs in the UK, worth approximately £690m to the economy – but like all grazing livestock, they can be infected with gut dwelling roundworm parasites. This can lead to a reduction in growth and carcass quality, costing farmers up to 10% of sale value. These infections are estimated to cost the UK in the region of £80 million per annum.

Animals are usually infected with several different nematode species at the same time. Chemical wormers (anthelmintics) have been routinely used to control roundworms which has led to the development of anthelmintic resistance in small ruminant nematodes.

This rise in resistance poses a threat to both livestock production and future food security which is why developments in precision treatments to target specific animals could offer huge benefits long term.

Scientists at the Moredun Research Institute have developed a method to identify poorly growing lambs using an electronic weight crate, allowing for targeted selective treatment, without the need to worm an entire flock.

Lead scientist Fiona Kenyon explained: “We have been looking at ways to slow down the rates of resistance by treating select animals within groups who are suffering due to infection and treating them specifically. Although all grazing animals can be affected, we know that the majority of worms are found in a minority and through identifying poorly growing animals we hope to reduce the time and cost of treating a whole flock,” she continued.

“We have been looking at predicted weight targets in a group of lambs linked to their EID and as the animal passes through a weight crate we are able to tell if it is set to meet its target and if not, we treat it. We have tested this approach on selected individuals over several years of studies and we have been able to reduce anthelmintics by 40%.”

Ms Kenyon explained that treatments are given before animals have lost weight which means they can get to the root of the problem before an animal loses condition. Livestock owners are urged to invest in a weight crate which can range in costs from £3000 for a more basic model to up to £10,000 for a more advanced one.

Ms Kenyon continued: “Historically the advice given was to treat all of your animals, however, the majority of animals don’t have a huge worm burden so as a farmer you are wasting time and drug costs treating animals which see no benefit. Through this targeted method we are also not seeing huge contamination of pasture in subsequent years because the whole flock hasn’t been treated,” she concluded.

Smaller producers are advised when dosing ewes to leave ewes carrying single lambs that look healthy alone and to carry out egg count monitoring by taking faecal samples from grazing animals from a group and sending them off to be monitored.