Worming like a winner: A guide to a sustainable UK sheep flock

Endoparasites have co-evolved with sheep but modern, intensive management techniques have increased their negative impact on productivity. Anthelmintics have been historically over-used, resulting in our current problems. The situation is concerning because anthelmintic resistance has the potential to stop sheep farming in the UK; however there are management changes that can be made to not only prevent anthelmintic resistance, but even reverse it.

Across the globe farmers and researchers are employing different ways to tackle this problem, from breeding beneficial genetic traits into their sheep to using appropriate rotational grazing and testing and implementing refugia, among many others. This report aims to collate the knowledge into a one-stop-shop for controlling sheep worms.

New Zealand farmers are taking the threat of anthelmintic resistance seriously as several have already discovered triple anthelmintic resistance on their farms. Implementing key ideas such as refugia and targeted selective treatments to reduce the reliance on chemicals is essential, alongside improving grass utilisation to increase the available nutrition, aiding the sheep’s natural defences. The historical mixed farm is a successful way to manage parasites on pasture using different stock classes to act as vacuumers following contaminators. Ideally lambs should graze the clean pasture first, followed by ewes, allowing some refugia, then cattle to hoover up the parasites without becoming infected themselves. Genetics play an important role in flock susceptibility so understanding your ram breeder’s direction on parasite management is also crucial. For the future, new and alternative ideas and products coming from outside the sector in Africa and elsewhere may provide additional alternative options.

When tackling on-farm resistance the first step is to understand what is happening in your business as without this appropriate changes cannot be made. Regular non-subjective test protocols, such as faecal egg counts, should be implemented monthly across the flock alongside understanding the main risk factors that lead to high parasite burdens. Parasite control should be developed on a farm-by-farm basis as the use of pasture and productivity aims are specific to each business. Therefore it is important to use tailored advice from properly informed advisors who understand the complexities of the system as a whole.

Miranda's report summary video can be viewed on the Nuffield Farming YouTube Channel.