RESUMO
Three trials including 42 sheep were conducted in Brazil or Germany to evaluate the therapeutic (two trials) and prophylactic (one trial) efficacy of an ivermectin controlled release capsule (CRC) against Psoroptes ovis infestation. In one therapeutic trial naturally infested sheep were used while in the other trials infestations were experimentally induced. In each trial half of the animals were treated on Day 0 with one ivermectin controlled release capsule that delivers ivermectin at a rate of 1.6 mg/day for approximately 100 days, that is 20 mcg/kg/day to a 80 kg animal, while the other half remained untreated. In both therapeutic trials mites were counted in skin scrapings and their presence was recorded at predilection sites one day before treatment and at weekly intervals from Day 7 to Day 56. In the trial conducted to evaluate the prophylactic efficacy the sheep were experimentally infested with P. ovis 21 and 28 days post-treatment and mites were counted and recorded at predilection sites on Days 42, 49 and 56. The ivermectin controlled release capsule was completely effective in eliminating the P. ovis mites within 28 days of administration and it prevented the establishment of an infestation of P. ovis induced 21 and 28 days after administration.
Assuntos
Inseticidas/administração & dosagem , Ivermectina/administração & dosagem , Infestações por Ácaros/veterinária , Ácaros , Doenças dos Ovinos/prevenção & controle , Animais , Brasil , Preparações de Ação Retardada , Feminino , Alemanha , Inseticidas/uso terapêutico , Ivermectina/uso terapêutico , Masculino , Infestações por Ácaros/prevenção & controle , Ácaros/crescimento & desenvolvimento , Ovinos , Pele/parasitologiaRESUMO
The prophylactic efficacy of ivermectin against navel or scrotal myiasis in calves was evaluated in eight trials in Argentina and Brazil. In two trials, calves were injected subcutaneously with ivermectin at a dosage of at least 200 microg kg(-1) within 24 h of birth. In the other six trials, two with two-month-old calves and four with four-month-old or older calves, all calves were treated with ivermectin at a dosage of at least 200 microg kg(-1) immediately after castration. In all trials, calves were maintained together on pasture and naturally exposed to Cochliomyia hominivorax. Navel and scrotal wounds were examined for myiasis daily for at least 14 days. Incidence of navel and scrotal myiasis was significantly lower (P < 0.01) in treated calves than in control calves.