Project codes: - S-04-01, S-06-02 

Team and Leader Alistair Carson

Organisations Involved  Alistair Carson (ARINI) and Maurice McCoy (VSD)

Background and Summary

Effective control of gastrointestinal parasites is crucial in maintaining good health and performance of lambs and thereby minimising labour requirements in sheep production systems. The indiscriminate use of wormers is likely to be inefficient from a labour and economic point of view and even more importantly this type of parasite control is under threat from the growing resistance of the infectious nematode parasites to available anthelmintics.

There is a strong relationship in sheep between the number of eggs in faeces and the number of worms in the gut. On-farm monitoring systems of faecal egg counting being evaluated in a study being undertaken by ARINI and the Veterinary Science Division. As part of this study worm burdens in lambs over the grazing season are being investigated and the efficacy of selected parasite drugs being investigated in a range of lamb genotypes. The first objective of the proposed study is to build on the fundamental work being undertaken currently and evaluate the potential for on-farm monitoring of faecal egg counts to direct and monitor worm control strategies on a sound epidemiological basis for hill and lowland sheep production systems.

Commercial selection for genetic resistance to gastrointestinal parasites in sheep is now underway in a number of countries. In the UK, selection for resistance has begun in the Texel and Suffolk sire referencing schemes. Selection is based on FEC measurements in growing lambs with in the future genetic markers likely to be used to increase the rate of genetic progress in worm resistance. The second objective of this programme is to investigate the effects on anthelmintic requirements and lamb performance of using sires with high estimated breeding values for worm resistance in both hill and lowland environments. As nutrition is also an important factor in developing immunity to parasites it is crucial that genetic approaches to worm resistance are tested over a range of environments.

In summary this proposal aims to develop improved worm control strategies for the Northern Ireland sheep industry. Developing FEC monitoring systems to direct and control worming strategies and exploiting genetic resistance to worms are key aspects in developing integrated pest management systems for worm control in sheep, which will form the basis of sustainable worm control.


To be completed December 2006 - results will be made available in Spring 2007


Project News Update

An extension was commissioned on this project in 2004/2005 financial year.