16 August 2002

Technique relies on right interpretation

EFFECTIVE use of faecal egg counting to improve worm control relies on expert interpretation of results, but this must come at an affordable cost.

That is the view of Kym Abbott, senior lecturer at Londons Royal Vet College. Dr Abbott has considerable experience of faecal egg count monitoring in Australia, which he has been putting into practice in UK flocks since his arrival in the country six months ago.

"Faecal egg count monitoring has two roles. It reduces the rate at which anthelmintic resistance develops and enables wormers to be targeted so they are given when necessary, but withheld when not."

However, using the technique effectively depends on more than simply counting eggs and drenching when they exceed a certain number, warns Dr Abbott. "Information on weather, a farms parasite history, management and lamb age must also be taken into account.

"For nematodirus faecal egg counting may not be the best tool for highlighting a problem because outbreaks can sometimes occur before egg counts are high enough to detect. However, it can help with strategic control of this parasite by highlighting the best time to drench lambs in order to reduce pasture contamination the following season."

As parasite control is a complex subject, Dr Abbott is sceptical about do it yourself faecal egg counting kits. "You could soon come unstuck without expert advice."

But advice and capacity for processing samples must be better co-ordinated than currently if more producers are to make use of the technique, says Dr Abbott. "We need to get local vets more involved and develop their experience of using the technique.

"Vet labs, which have the ability to do counts, must be able to handle large numbers of samples at an affordable cost. Currently, samples are usually only examined when information is needed to diagnose a health problem on a farm, rather than for monitoring purposes." &#42