background: leptospirosis is a worldwide zoonosis causedby leptospira interrogans. leptospirosis results in decreasedmilk production, abortion, stillbirth, infertility and mortality,which causes financial loss in the cattle industry. objectives:the aim of this research was to perform a serological andbacteriological study of leptospirosis in 6 industrial dairy herdsand 3 feedlots with previous ...