Anatomical distribution and population dynamics of Rhipicephalus (Boophilus) microplus in cattle in the municipality of Óleo, São Paulo

Abstract

Rhipicephalus (Boophilus) microplus infestation is responsible for significant economic losses in cattle industry. The use of acaricides at strategic times and selection of resistant animals can minimize economic losses. This study aimed to determine the anatomical distribution and population dynamics of R. microplus in the municipality of Óleo, state of São Paulo. This study was conducted using eight male cattle, crossbred zebu-taurine (in accordance with the regional herd). Female R. (B.) microplus, greater than 4 mm, present in the right side of the animals were counted between April 2012 and March 2013. The highest tick number per animal was noted in October (128.25), and the lowest in April (35.5), with three infestation peaks during the study, in May, October, and December, which were influenced by the minimum and maximum mean temperature and rainfall. Among the cranio-caudal regions (anterior, median, and posterior), the posterior had the highest mean tick number, and the anterior had the lowest. The minimum temperature, rainfall, and solar radiation interfered with infestation of dorsoventral regions: in cold months, the lowest infestations were found in the mixed area (ear and tail); in the warm months, in the high region (head, neck, upper ribs, flank, and rump). The lower region (dewlap, cranial limb, lower ribs, abdomen, prepuce, scrotum, and lower limb) always had the highest mean tick number. The tick numbers of the caudal limb and crotch showed strong correlation with the total tick number (+0.88 and +0.70, respectively). These data, grouped according to median, posterior, and crotch regions, showed a stronger correlation with the total tick number (+0.96, +0.90, and +0.70, respectively).