LLEYN sheep breeders across the three counties are now able to select animals for their resistance to roundworm.

Selecting estimated breeding values (EBV) for roundworm resistance is something a number of breeders have been keen to embrace, including Edward Collins, who has a Lleyn flock at Bearwood Farm, Pembridge, Herefordshire.

He is a member and secretary of Performance Recorded Lleyn Breeders (PRLB) which obtained funding to work with Glasgow University to look at worm resistance in sheep.

His flock is performance recorded with Signet Breeding Services and each animal is given an EBV for the most important genetic traits; an eight-week weight EBV, mature size EBV, litter size EBV, maternal ability EBV, scan weight EBV, muscle depth EBV and fat depth EBV.

He has been involved in the project since 2014 and also takes foecal egg count (FEC) and saliva samples of his lambs to produce a FEC EBV.

The breeder group has found that lambs are now being identified that are genetically more resistant to the common British round worm.

Edward says on his website that the impact of the research will have massive implications to commercial farmers in the future, with worm resistance amongst the UK flock a big problem.

Researchers at Glasgow University found the antibody response against the larval stage of a roundworm infection can be used as a biological marker for host response to infection.

Immunoglobulin A (IgA) is an antibody critical to immune function in mucous membranes. Measuring this in saliva provides a new phenotype through which differences between sheep can be identified.

High levels of IgA have been shown to regulate both worm growth and fecundity, which leads to decreased egg output.

AHDB Beef & Lamb supported the collection of saliva IgA and faecal egg count (FEC) samples for the study by awarding the PRLB group a Farm Innovation Grant in 2013.

In 2015, a further AHDB grant was made to enable geneticists at Scotland’s Rural College (SRUC) to analyse the raw data and investigate genetic influences on saliva IgA and convert these new measurements into EBVs which will enable breeders to make more informed decisions.

Sam Boon, Signet breeding manager, said: “Since 2013, 7,899 Lleyn saliva samples have been collected and uploaded to the Signet database. When combined with the ongoing collection of FEC data, this has created a large commercial dataset on which to estimate heritability values for this new trait and study the genetic relationships between this and the FEC EBVs.”

The new Saliva IgA EBVs are expressed in units of IgA activity; high EBVs mean that an animal is genetically better at dealing with worms. This is in contrast to the expression of FEC EBVs, where breeders are reminded that low, negative values are indicators of the breeding potential to put fewer eggs out onto pasture.

Sam said: “The Lleyn breeders involved are very enthusiastic about the potential for this new technology and its application to the selection of genetically superior sheep.

“In the future, planned matings will take place between high EBV animals for these traits to see the impact it has on progeny performance.”

More information can be found at signetfbc.co.uk