COMPLETING FAECAL egg counts on farm saves both time and money, but it may be worthwhile having regular quality control samples checked by a professional lab.

A Northern Ireland study found some worm egg types were mis-identified and worm egg counts were inaccurate using on-farm kits, reports Maurice McCoy. of the Department of Agriculture and Rural Development”s Vet Services Division.

“It is a matter of ensuring kit users are well enough trained in the first place and then continuing that education with refresher courses. It is also useful to send identical samples to a lab to obtain a control result. This will help identify whether egg counting skills are accurate.

“The best time to have this control sample checked is probably the first two or three samples of the summer, as little egg counting will have been done for several months over winter,” he explains.

“Once producers are confident they are accurately estimating the number of eggs in each sample and identifying the correct species there is probably no need to have further control samples checked until late summer or the next year.”

It also takes time to become accustomed to using the microscope when checking faecal samples, so users may find it better to practice using the microscope before using it to make worming decisions.

Identifying each egg species can be difficult, so Mr McCoy suggests using a reference picture which accurately shows what will be seen down the microscope in a faecal sample.

“For the trial, we supplied participants with a picture which had all the species on one picture at the size they would be viewed under the microscope.”

One particular problem encountered by participants was differentiating between Strongyloides species worm eggs from strongyle worm eggs.

“Strongyloides is much less of a problem than strongyle, so mistaking one for the other may result in unnecessary dosing.

“This may in turn lead to an acceleration of the development of anthelmintic resistance,” he warns. jonathan.long@rbi.co.uk