Faecal egg counts as a guide for drench use

Abstract

Extract The first of the Feature Review Series published in a recent issue of the New Zealand Veterinary Journal (Vol 49, No. 6, December 2001) has provided a number of well presented and authoritative articles regarding the control of nematodes in sheep. In view of the importance of these papers, it is disappointing, therefore, to find that some of my work should be misrepresented in one of them. I refer to the section relating to “Faecal Egg Counts as a Guide for Drench Use” on Pp 218–9 of the article by Vlassoff et al (2001). Here it is stated, and I quote: “McKenna (1981) showed there was a reasonable correlation (r=0.74) between mean FECs and worm burdens in lambs using the following FEC classes: ‘Low’ being <500 epg, ‘Moderate’ being 600–2000 epg, and ‘High’ being >2000 epg; in that study, these FEC classes were shown to be of considerable diagnostic value. However, these FEC classes are broad and subjective, and their threshold values are higher than those deemed significant by many farmers; consequently, sheep are often treated when group mean FECs are considerably lower than 500 epg.”