Immunoglobin A (IgA) is an antibody produced by white blood cells that binds to parasites in the gut, reducing the worm’s ability to grow and reproduce. IgA levels can be measured easily by taking a saliva sample from the animal. High saliva IgA levels are negatively correlated to high faecal egg counts (FEC). So an animal with a high IgA level is more likely to expel less worm eggs out on to pasture – a trait that if selected for, could allow us to breed sheep that are genetically better at dealing with parasitic challenge. This is vital in an age where anthelmintic resistance is becoming more and more prevalent.
In 2013, the performance recorded Lleyn breeders group (PRLB) won a farm innovation grant that lead to the collection of thousands of individual FEC and saliva IgA measurements. This has meant that the Lleyn breed is the first to receive EBVs for saliva IgA in their 2017 genetic evaluations.
This year a grant has been awarded to the Romney High-Index Scheme (RHIS) group that work together to take Romney genetics forward. The funding granted from The Organic Research Centre (ORC) and AHDB/Signet will allow RHIS members to collect individual FEC and Saliva IgA measurements in the same way as the Lleyns. Should they do this for a number of years, collecting many phenotypes, then it is highly likely that Romney sheep will also receive EBVs for Saliva IgA in the future.
The RHIS group will begin sampling their lambs from the beginning of August 2017 through to the end of September. The Romney project is part of a much wider goal run by an industry collaboration known as the innovation for sustainable sheep and goat production in Europe (iSAGE) which aims to make the European sheep and goat sectors more sustainable, competitive and resilient to future challenges.
The members of the RHIS group involved and sampling in 2017 will be:
P H & P E Skinner – Aragon Romneys
G H Bates – Becket Romneys
H V Langrish – Pickney Bush Romneys
A Barr & Son Ltd – Pivington Romneys
G L Boulden & Sons – Ruffins Romneys
The project recently featured on page 48 of Farmers Weekly issue 14 July 2017 and details how Mr Hugh Skinner (Aragon flock) deals with worm challenges now and going into the future – the online article is available here.