SciELO - Scientific Electronic Library Online

SciELO - Scientific Electronic Library Online


LOPES, Welber Daniel Zanetti et al. Ivermectina e abamectina em diferentes doses e vias de aplicação contra larvas de Cochliomyia hominivorax em bolsas escrotais de bovinos recém-castrados, provenientes da região sudeste do Brasil. Cienc. Rural [online]. 2013, vol.43, n.12, pp.2195-2201. ISSN 1678-4596.


Study demonstrates ineffectiveness of ivermectin and abamectin in preventing scrotal myiasis in cattle



Researchers from Universidade Estadual Paulista "Julio Mesquita",  Jaboticabal/CPPAR, São Paulo, Brazil, demonstrated that invermectin and abamectin are ineffective in preventing scrotal myiasis in cattle. The study was published in Ciência Rural journal, v.43, n.12, of December 2013.

The experiment evaluated the preventive efficacy of ivermectin and abamectin administered in different routes (subcutaneous, intramuscular and pour-on) and doses (200 and 500 mcg kg-1) against Cochliomyia hominivoraz. Animals of six farms in the state of São Paulo and Minas Gerais, Brazil, were used. For each study, the researchers selected from 30 to 45 uncastrated bulls. On day zero of the study, the researchers conducted the process of castration of animals. These were evaluated from the 3rd to the 14th day after castration process / treatment.

The results showed that the efficacy values for both active principles were lower than 30% near the tenth day after treatment. In five experiments, both ivermectin as abamectin were ineffective on the tenth day post-treatment.

According to the researchers Alvimar José da Costa and Welber Daniel Zanetti, the results obtained in this study can assist farmers in choosing a particular formulation to be used concurrently with the process of castrating cattle.

The research is one of the few recent studies that evaluate the efficacy of formulations against screwworm. "The fact of ivermectin and abamectin are not effective against larvae of C. hominivorax underscores the importance of the study," evaluate the researchers.



Researcher: Welber Daniel Zanetti Lopes