Efficacy of abamectin against nematodes in cattle

Abstract

Eight controlled trials were conducted, using 96 cattle of European breeds, to evaluate the efficacy of abamectin against natural and artificially acquired infections of adult and fourth-stage larvae of all the economically important gastrointestinal nematodes and lungworms in Germany and the United Kingdom. Half the animals were treated on one occasion with abamectin at a dose of 200 micrograms/kg bodyweight given subcutaneously while the other half remained untreated. Worms were counted 14 or 21 days after treatment or 28 days after the last infection. The treatment was highly effective (> 99 to 100 per cent) (P < 0.05) at removing immature (L4) stages and adult worms of the following species: Ostertagia ostertagi (inhibited larvae included), Trichostrongylus axei, Haemonchus contortus, Bunostomum phlebotomum, Cooperia species Oesophagostomum radiatum and Dictyocaulus viviparus. Naturally acquired adult C surnabada and Trichuris discolor infections were also significantly (P < 0.05) reduced. For Nematodirus helvetianus the efficacy varied from 89.8 to > 99 per cent (P > 0.1 to < 0.01). Abamectin gave full protection against the gastrointestinal nematodes O ostertagi, H contortus, Cooperia species and O radiatum for at least seven days and against the lungworm D viviparus for at least 14 days after treatment.

Evaluation of the persistence of the effect of ivermectin and abamectin against gastrointestinal and pulmonary nematodes in cattle

“…For routine purposes, infective Cooperia species larvae cannot be identified to a species level and therefore the exact composition of the mixture of Cooperia larvae was not known. The composition of the burden of Cooperia species observed in both trials was similar to that observed after the use of the same isolates in previous studies (Heinze‐Mutz and others 1993, Pitt and others 1996, B. N. Kunkle, unpublished observations). The infection rates varied between the species.…”

Eficácia carrapaticida e preventiva sobre Rhipicephalus microplus da associação de abamectina com fluazuron em bovinos artificialmente infestados

“…Sua eficácia já foi demonstrada para o controle de ectoparasitos e nematoides de bovinos e sua eficácia é superior a 90% durante em média 28 dias (Abridi et al, 1992;Cruz et al, 1993;Heinze-Mutz et al, 1993a, 1993bGuglielmone et al, 1999).…”