title: Population dynamics and evaluation of the partial selective treatment of crossbreed steers naturally infested with Rhipicephalus (Boophilus) microplus in a herd from the state of Minas Gerais in Brazil.
abstract: The present study aimed to evaluate the population dynamics of Rhipicephalus (Boophilus) microplus over a period of 13 months on a rural property located in the state of Minas Gerais in southeastern Brazil. Animals were treated for ticks indoors by whole body spraying when R. (B.) microplus had an average count equal or more than 30 ticks. The study also evaluated the possibility of a partial selective treatment for bovines to control R. (B.) microplus in which only a percentage of the population would be treated (specifically those bovines with tick counts of ≥20. Moreover, we examined the percentage of the population of R. (B.) microplus present on experimental bovines that did not come into contact with the chemical compounds used in the partial selective treatment. We concluded that in this particular region of Brazil, the crossbreed steers support up to five R. (B.) microplus generations per year and that the number of generations was primarily affected by the pluviometric precipitation. We sprayed the bovines with chemicals seven times during the course of the study. The results of the partial selective treatment method revealed that during the rainy and the dry periods, 42.1% to 60.0% and 61.9% to 79.2% of the animals, respectively, fulfilled the criteria to receive a chemical treatment to reduce the number of cattle ticks. In consideration of the need to slow the development of tick resistance with the chemical compounds used in the spraying treatment, the results showed that the percentage of animals that did not require treatment is not relevant. This was evidenced by the result that bovines that presented tick counts of ≥20 during the dry and rainy periods represented 91.5% and 90.6% of the total recorded R. (B.) microplus populations, respectively. Only 8.7% of the tick population remained free from exposure to acaricides during the 13 months of the study, which is an important point when considering the adoption of the partial selective treatment method. Future studies with larger herds must be conducted on these topics; however, our results suggest that the partial selective treatment method most likely will not slow the development of resistance in this R. (B.) microplus population against the chemical compound used in this study.
authors.affiliation: Faculdade de Ciências Agrárias e Veterinárias, UNESP/CPPAR, Access route Prof. Paulo Donatto Castellane, CEP: 14884-900 Jaboticabal, São Paulo, Brazil.
authors.forename: Lucas Vinicius Costa
authors.initials: LV
authors.lastname: Gomes
authors.affiliation: Faculdade de Ciências Agrárias e Veterinárias, UNESP/CPPAR, Access route Prof. Paulo Donatto Castellane, CEP: 14884-900 Jaboticabal, São Paulo, Brazil; Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO 74605050, Brazil. Electronic address: wdzlopes@hotmail.com.
authors.forename: Welber Daniel Zanetti
authors.initials: WD
authors.lastname: Lopes
authors.affiliation: Faculdade de Ciências Agrárias e Veterinárias, UNESP/CPPAR, Access route Prof. Paulo Donatto Castellane, CEP: 14884-900 Jaboticabal, São Paulo, Brazil.
authors.forename: Weslen Fabricio Pires
authors.initials: WF
authors.lastname: Teixeira
authors.affiliation: Faculdade de Ciências Agrárias e Veterinárias, UNESP/CPPAR, Access route Prof. Paulo Donatto Castellane, CEP: 14884-900 Jaboticabal, São Paulo, Brazil.
authors.forename: Willian Giquelin
authors.initials: WG
authors.lastname: Maciel
authors.affiliation: Faculdade de Ciências Agrárias e Veterinárias, UNESP/CPPAR, Access route Prof. Paulo Donatto Castellane, CEP: 14884-900 Jaboticabal, São Paulo, Brazil.
authors.forename: Breno Cayeiro
authors.initials: BC
authors.lastname: Cruz
authors.affiliation: Faculdade de Ciências Agrárias e Veterinárias, UNESP/CPPAR, Access route Prof. Paulo Donatto Castellane, CEP: 14884-900 Jaboticabal, São Paulo, Brazil.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Felippelli
authors.affiliation: Faculdade de Ciências Agrárias e Veterinárias, UNESP/CPPAR, Access route Prof. Paulo Donatto Castellane, CEP: 14884-900 Jaboticabal, São Paulo, Brazil.
authors.forename: Carolina
authors.initials: C
authors.lastname: Buzzulini
authors.affiliation: Faculdade de Ciências Agrárias e Veterinárias, UNESP/CPPAR, Access route Prof. Paulo Donatto Castellane, CEP: 14884-900 Jaboticabal, São Paulo, Brazil; UNICASTELO-Universidade Camilo Castelo Branco, Brazil.
authors.forename: Vando Edésio
authors.initials: VE
authors.lastname: Soares
authors.affiliation: Faculdade de Ciências Agrárias e Veterinárias, UNESP/CPPAR, Access route Prof. Paulo Donatto Castellane, CEP: 14884-900 Jaboticabal, São Paulo, Brazil.
authors.forename: Daniel Pacheco
authors.initials: DP
authors.lastname: de Melo
authors.affiliation: Faculdade de Ciências Agrárias e Veterinárias, UNESP/CPPAR, Access route Prof. Paulo Donatto Castellane, CEP: 14884-900 Jaboticabal, São Paulo, Brazil.
authors.forename: Murilo Abud
authors.initials: MA
authors.lastname: Bichuette
authors.affiliation: Faculdade de Ciências Agrárias e Veterinárias, UNESP/CPPAR, Access route Prof. Paulo Donatto Castellane, CEP: 14884-900 Jaboticabal, São Paulo, Brazil.
authors.forename: Geraldo
authors.initials: G
authors.lastname: Gonçalves Junior
authors.affiliation: Faculdade de Ciências Agrárias e Veterinárias, UNESP/CPPAR, Access route Prof. Paulo Donatto Castellane, CEP: 14884-900 Jaboticabal, São Paulo, Brazil.
authors.forename: Alvimar José
authors.initials: AJ
authors.lastname: da Costa
mesh_terms: D056810:Acaricides / Q000008:administration & dosage*; D000818:Animals; D001938:Brazil; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy* / Q000469:parasitology*; D003140:Communicable Disease Control / Q000379:methods* / Q000592:standards*; D059208:Parasite Load; D011157:Population Dynamics; D048494:Rhipicephalus / Q000502:physiology*; D012621:Seasons; D013984:Tick Infestations / Q000469:parasitology / Q000662:veterinary*
chemical_list: D056810:Acaricides
keywords: Generations; Partial treatment; Resistance; Southern cattle tick