Abstract :
The objective was to evaluate long-acting moxidectin (Cydectin® 2% LA for sheep) against
trichostrongylids in sheep. We performed a blocked, parallel, controlled clinical trial. We
included 45 ewe-lambs, allocated into treated (n = 30, 1.0mgmoxidectin per kg bw, subcutaneously
at base of ear on D 0) or controls (n = 15). Animals had been naturally infected
(pre-treatment geometric mean epg counts: 233 and 249, respectively) and throughout
the study grazed at the same pasture. Fortnightly, we collected faecal samples and performedestablishedparasitological
techniques (epg counts, coprocultures).We usedanalysis
of covariance for post-treatment results, using pre-treatment counts as covariate, treatment
as fixed effect, block as random effect. Geometric mean epg counts in treated animals were
0 up to D 112, 1 on D 126, 4 on D 140 and 13 on D 161. Respective figures for controls were
369–820 up to D 140 and 168 on D 161 (p < 0.05). Persistent efficacy (>90%) was 140 d for
Teladorsagia, 119d for Haemonchus and 115 d for Trichostrongylus. This is the first reported
clinical trial of efficacy of long-acting moxidectin in sheep in Europe. Cydectin 2% LA was
found to be effective against trichostrongylids of sheep. The particularly long persistent
efficacy can provide new possibilities in formulating anthelmintic programs for sheep
