Comparação dos métodos de controles estratégico e seletivo na carga parasitária de Rhipicephalus microplus em rebanhos bovinos leiteiros

• Autor(a) principal: Vieira, Luciano da Silva
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/10520
• topic: Acaricida; Brasil; Carrapato do bovino; Tristeza parasitária bovina; Acaricide; Brazil; Cattle tick; Cattle fever tick; Anaplasmosis; CIENCIAS AGRARIAS::MEDICINA VETERINARIA

Rhipicephalus microplus is one of the main ectoparasites of economic importance for cattle in tropical and subtropical regions, causing drop in milk production and transmitting pathogenic agents such as Anaplasma and Babesia. Therefore, constant studies on treatment schemes for parasite control are necessary to minimize the damage and losses that follow infestations by this arthropod. In this way, the present study aimed to compare two methods for R. microplus control, the strategic method and the selective method, in dairy cattle herds, aiming to provide support to the technical guidelines on the most efficient control method of the parasitic load. In the strategic method, seven treatments with spray acaricides were carried out every 21 days, starting in November. In the selective method, treatments with acaricides were performed only on animals that had an infestation equal to or greater than 40 engorged females. Only 5% of animals submitted to the selective method received treatment in November. The average of tick counts was lower in the strategic method compared to the selective method, in December. The maximum peak of infestation occurred in January, in both control methods, with no significant difference, persisting until February. No animal of the strategic method had an infestation greater than 40 engorged females in March. However, the parasitic load in both control methods was similar in the second evaluation in March. The averages of counts in the strategic method were lower in the months of April (10.9) and May (16.9) compared to the averages observed in the selective method (56.3 and 48.4). Yet, it was necessary to carry out tactical treatments in the strategic method, after the treatment scheme, in up to 16.7% of the animals in April and up to 50.0% in May, while in the selective method, the treatments varied from 42.8 to 88.8% in April and in May it varied from 28.6 to 75.0%. The total count of R. microplus was 5,036 engorged females in the strategic method, while in the selective method there were 13,829 engorged females in the study period. Therefore, it is concluded that the treatment scheme for control of R. microplus significantly interfered in the parasitic load of dairy cows, favouring the maintenance of acceptable levels of parasitism when the strategic method of tick control was implemented compared to the adoption of the selective method.