First report of the efficacy of a fluralaner-based pour-on product (Exzolt® 5%) against ectoparasites infesting cattle in Brazil

Abstract

Background This study describes the effectiveness of a novel active pharmaceutical ingredient, fluralaner (isoxazoline class), against important ectoparasites infesting cattle in Brazil. Methods A total of 13 studies involving a 5% fluralaner-based pour-on formulation (Exzolt 5%; further referred to as Exzolt) were conducted. Specifically, the effectiveness of this formulation was studied against Rhipicephalus microplus (6 studies), Cochliomyia hominivorax larvae (4 studies), Dermatobia hominis larvae (1 study) and Haematobia irritans flies (2 studies). Results The therapeutic efficacy of Exzolt was found to exceed 98% at 4 days post treatment (DPT), while persistent efficacy (> 90% efficacy) against repeated infestations of R. microplus was observed for up to 79 DPT. In field studies, ≥ 98% therapeutic efficacy was demonstrated at all study sites by 7 DPT, and a persistent efficacy (> 90% efficacy) was observed for 42, 49 or 56 DPT. Exzolt prevented C. hominivorax eggs from developing to the larval stage, thus mitigating the development of myiasis in cattle naturally and artificially infested with this screworm. The efficacy of Exzolt against D. hominis larvae was 98% at 3 DPT, while persistent efficacy (> 90% effectiveness) was found to last for up to 70 DPT. Against H. irritans, Exzolt showed therapeutic efficacy (≥ 90%) within the first day of treatment at both study sites, while persistent efficacy (≥ 90%) was observed for 7 DPT at one site and for 21 DPT at the other site. Conclusions Overall, the results from these studies confirm that Exzolt is therapeutically efficacious against the most important ectoparasites infesting cattle in Brazil. The novel active pharmaceutical ingredient, fluralaner, provides a new treatment option for farmers to control cattle ectoparasites, especially where there is resistance to other chemical classes. In addition, an effective control of ectoparasites will improve overall cattle health and well-being as well as production. Graphical Abstract

Efficiency of fluralaner pour-on in different strategic control protocols against Rhipicephalus microplus on Brangus cattle in a tropical area

“…All treatments were performed with a formulation of 5% fluralaner (Exzolt ® 5%—MSD Saúde Animal), administered via pour-on treatment at a dose of 1 mL/20 kg and exhibiting efficacy above 95% between the 7th and 49th day after treatment. This product was chosen owing to the need to use an acaricide with proven efficacy against ticks [ 11 ] and with no previous reports of resistance.…”

“…Fluralaner, a molecule belonging to the pharmaceutical group of isoxazolines that is widely used for the control of mites and insects in companion animals, has a long period of action, rapid absorption, and broad spectrum [ 10 ] and is a new alternative for the control of Rhipicephalus spp. in cattle [ 11 ]. To maximize the results and delay resistance, this molecule should be used sustainably and, based on data from field studies and strategic control protocols, allowing for effective control of ticks with minimal use of the chemical.…”

Two protocols using fluralaner for Rhipicephalus microplus strategic control on taurine cattle in a tropical region

“…For the animals in T01, strategic treatments were performed every 42 days [ 27 ], regardless of the degree of infestation, starting in mid-spring (November 2020) until late autumn (June 2021), with treatments performed on Days 0, + 42, + 84, + 126, + 168, and + 210, using the pour-on formulation containing fluralaner.…”