Paulino Bonatte Junior1,2, Jacqueline Cavalcante Barros1,3, Willian Giguelin Maciel4, Marcos Valerio Garcia5, Leandro de Oliveira Souza Higa5, Renato Andreotti6. 1. Universidade Federal de Mato Grosso do Sul, Programa de Pós-Graduação em Ciência Animal, Campo Grande, MS, Brazil. 2. Agropecuária Sanyo, Agua Clara, MS, Brazil. 3. Embrapa Gado de Corte, Avenida Rádio Maia, 830, Campo Grande, MS, CEP 79106-550, Brazil. 4. Instituto Laboratorial Elementary, Cajuru, SP, Brazil. 5. Bolsista DCR/Biotick / Embrapa Gado de Corte, Campo Grande, MS, Brazil. 6. Embrapa Gado de Corte, Avenida Rádio Maia, 830, Campo Grande, MS, CEP 79106-550, Brazil. renato.andreotti@embrapa.br.
Abstract
PURPOSE: The aim of this study was to evaluate four strategies for application of acaricides to control the tick Rhipicephalus microplus among infested cattle, and to show which of these has the best cost-benefit ratio. METHODS: For this, 72 cattle were selected and divided into four groups: Group 1 (G1): fipronil, pour-on; Group 2 (G2): fluazuron, pour-on; Group 3 (G3): moxidectin, injectable; and Group 4 (G4): chlorpyrifos 30 g, cypermethrin 15 g and fenthion 15 g, spraying (atomizing chamber). Every seven days, the numbers of semi-engorged females were counted and laboratory tests were conducted using different commercial technical-grade products for resistance monitoring. RESULTS: G4 showed the best percentage reduction, with the highest rate on the seventh day post-treatment (DPT) (83.23%). G3 was the second best strategy, with a percentage of inverse reduction such that the best results were on the 28th DPT (82.85%), while G1 and G2 reached their best results on the 21st DPT (32.63% and 2.79%). CONCLUSION: It was noteworthy that the formulation used in G4 was the only one that was efficient for strategic control and that, based on the economic analysis, was shown to be economically viable over the medium term due to the need for investment. The presence of a multidrug-resistant strain in the state of Mato Grosso do Sul in vitro, for the chemical bases amitraz, cypermethrin and cypermethrin + DDVP, is reported here for the first time.
PURPOSE: The aim of this study was to evaluate four strategies for application of acaricides to control the tick Rhipicephalus microplus among infested cattle, and to show which of these has the best cost-benefit ratio. METHODS: For this, 72 cattle were selected and divided into four groups: Group 1 (G1): fipronil, pour-on; Group 2 (G2): fluazuron, pour-on; Group 3 (G3): moxidectin, injectable; and Group 4 (G4): chlorpyrifos 30 g, cypermethrin 15 g and fenthion 15 g, spraying (atomizing chamber). Every seven days, the numbers of semi-engorged females were counted and laboratory tests were conducted using different commercial technical-grade products for resistance monitoring. RESULTS: G4 showed the best percentage reduction, with the highest rate on the seventh day post-treatment (DPT) (83.23%). G3 was the second best strategy, with a percentage of inverse reduction such that the best results were on the 28th DPT (82.85%), while G1 and G2 reached their best results on the 21st DPT (32.63% and 2.79%). CONCLUSION: It was noteworthy that the formulation used in G4 was the only one that was efficient for strategic control and that, based on the economic analysis, was shown to be economically viable over the medium term due to the need for investment. The presence of a multidrug-resistant strain in the state of Mato Grosso do Sul in vitro, for the chemical bases amitraz, cypermethrin and cypermethrin + DDVP, is reported here for the first time.
Authors: Guilherme M Klafke; Gustavo A Sabatini; Thais A de Albuquerque; João Ricardo Martins; David H Kemp; Robert J Miller; Teresinha T S Schumaker Journal: Vet Parasitol Date: 2006-08-09 Impact factor: 2.738