The tick-borne disease (TBD) brings great damages to cattle breeding. The most important etiologic agents are Babesia bigemina, B. bovis and Anaplasma marginale, being the tick Boophilus microplus the main vector. This work reports the occurrence of natural infection by hemoparasites of TBD in 36 calves with high ticks natural infestation submitted to chemoprophylaxis with 30 days year-old. The blood smears from animals of different ages were analized and were found B. bigemina (33.3%), B. bovis (11.1%) and A. marginale (13.9%). Six animals had clinical symptoms (16.7%) and one dead (2.8%). The number of clinical cases ocurred in consequence of an association of factors as high infestation of ticks and low passive immunity in period that calves had not developed enough active immunity.
Tick-borne disease; Babesia; Anaplasma; calves
