title: Effects of macrocyclic lactones on the reproductive parameters of engorged Rhipicephalus (Boophilus) microplus females detached from experimentally infested cattle.
abstract: The present study therefore assessed the deleterious effects of MLs (ivermectin, abamectin, doramectin and moxidectin) on the reproductive parameters of engorged Rhipicephalus (Boophilus) microplus females that naturally detached from experimentally infested cattle in two experiments. The following reproductive parameters of engorged female ticks were analyzed: female weight, egg mass weight, percentage of hatchability, percentage of reduction in oviposition, percentage of reduction in hatchability, reproductive efficiency and percent control/efficacy of formulations with respect to reproductive parameters. In the experiment I, statistical analysis of the data grouped into 5-days intervals revealed that pour-on application of abamectin (500 mcg/kg) had significantly (p ≤ 0.05) reduced engorged female weight, egg mass weight and percent hatchability on days 6-15, 6-20 and 11-20 post-treatment (p. t.) compared to the respective data for detached and pre-selected engorged females in the control group. The abamectin, demonstrated 33.41% of reduction in oviposition, 6.77% in hatchability and abamectin efficacy was of 13.99%. In the experiment II, statistically significant reductions (p ≥ 0.05) were observed in animals treated subcutaneous with ivermectin (630 mcg/kg), doramectin (700 mcg/kg) and moxidectin (1000 mcg/kg) relative to the control for days 6-40, 6-48 and 6-40 p. t., respectively. Ivermectin reduced hatchability only on days 16-20 p. t., whereas doramectin significantly reduced (p ≤ 0.05) hatchability on days 6-10 and 16-35 p. t. For moxidectin, deleterious effects on hatchability were observed on days 16-35 p. t. The percent reductions in oviposition of engorged female ticks were 46.31%, 62.17% and 61.02% with ivermectin, doramectin and moxidectin treatments, respectively. The percent efficacy of the formulations on the reproductive parameters of engorged female ticks was 21.22% for ivermectin, 36.03% for doramectin and 35.45% for moxidectin. Among the MLs assessed, doramectin and moxidectin had the highest acaricidal efficacies and the most deleterious effects on the reproductive parameters of engorged R. (B.) microplus females. However, future studies will be necessary to assess the extent to which these effects, along with acaricidal activity, can be used to control the ectoparasite in cattle.
authors.affiliation: CPPAR, Animal Health Research Center, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Via de acesso Prof. Paulo Donatto Castellani, s/n. CEP, 14884-900, Jaboticabal, São Paulo, Brazil. wdzlopes@hotmail.com
authors.forename: Welber Daniel Zanetti
authors.initials: WD
authors.lastname: Lopes
authors.forename: Weslen Fabricio Pires
authors.initials: WF
authors.lastname: Teixeira
authors.forename: Lucas Vinicius Shigaki
authors.initials: LV
authors.lastname: de Matos
authors.forename: Gustavo
authors.initials: G
authors.lastname: Felippelli
authors.forename: Breno Cayeiro
authors.initials: BC
authors.lastname: Cruz
authors.forename: Willian Giquelin
authors.initials: WG
authors.lastname: Maciel
authors.forename: Carolina
authors.initials: C
authors.lastname: Buzzulini
authors.forename: Flávia Carolina
authors.initials: FC
authors.lastname: Fávero
authors.forename: Vando Edésio
authors.initials: VE
authors.lastname: Soares
authors.forename: Gilson Pereira
authors.initials: GP
authors.lastname: de Oliveira
authors.forename: Alvimar José
authors.initials: AJ
authors.lastname: da Costa
mesh_terms: D056810:Acaricides / Q000494:pharmacology*; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000469:parasitology*; D005260:Female; D007559:Ivermectin / Q000031:analogs & derivatives / Q000494:pharmacology; D018942:Macrolides / Q000494:pharmacology*; D010058:Oviposition / Q000187:drug effects; D011897:Random Allocation; D012098:Reproduction / Q000187:drug effects; D048494:Rhipicephalus / Q000187:drug effects* / Q000502:physiology; D013984:Tick Infestations / Q000469:parasitology / Q000662:veterinary*
chemical_list: D056810:Acaricides; D018942:Macrolides; C048324:abamectin; D007559:Ivermectin; C084101:doramectin; C027837:moxidectin
keywords: Engorged females; Macrocyclic lactones; Reproductive parameters; Rhipicephalus (Boophilus) microplus