Perfil ectoparasitário em bovinos leiteiros mestiços da microrregião de São João Del-Rei, Minas Gerais, Brasil

The aim of the present study was to evaluate the profile of ectoparasites infesting dairy cattle and calves from properties located in the micro region of São João del-Rei, State of Minas Gerais, Brazil,as well as its seasonal variations, in order toprovide information thataids the control of such parasite infestations. A total of 224 dairy cows and 112 calves, belonging to 15 different rural properties, were evaluated by observation and manual palpation for counting parasites (botfly, ticks,and larvae).Dermatobiahominisbotfly exhibited a prevalence of 64.29% on dairy cows, whereas the tick Rhipicephalus(Boophilus) microplusand the fly Musca domesticashowed 59.38% and 43.30% of prevalence, respectively. Among calves,theprevalencesof ectoparasites were 32.14% for D. hominis, 29.46% for R. (B.) microplusand 31.15% for M. domestica.Prevalence and abundance of all ectoparasites were higher in adults (p < 0,001). Only adults were used in the seasonalcomparisonsbecause data weremore representative and trustable. Prevalences of D. hominisand M. domesticawere significantly different between the dryand rainy season, being D.hominis exhibiting lower values during the dry season (p < 0.001) and M.domesticaduring the rainy season (p < 0.001).Suggestively, the seasons influence parasite infestation rates.It is recommendedperforming periodical andlong term studies on parasitology and epidemiology, to establish strategies forsanitary management that minimizes the degree of parasite infestation and improve the productivity in this microregion.