COMPARISON OF 3 METHODS OF IMMUNIZATION AGAINST BOVINE ANAPLASMOSIS - EVALUATION OF PROTECTION AFFORDED AGAINST FIELD CHALLENGE EXPOSURE

  • 1 January 1980
    • journal article
    • research article
    • Vol. 41  (7) , 1066-1068
Abstract
The efficacy of 3 immunization methods for bovine anaplasmosis was tested on 88 yearling Normandy cattle which were challenge-exposed under field conditions in an enzootic zone in Colombia, South America. Thirty cattle were immunized (premunized) with a presumed mild Colombian isolate of Anaplasma marginale, 29 with an attenuated A. marginale of ovine origin and 29 were exposed to a virulent A. marginale stabilate of Colombian origin. Non-vaccinated cattle (29) served as controls. Parasitemia, packed cell volume, body weight, and complement-fixation antibody response were monitored to determine host response to challenge exposure. The calves experienced a Babesia challenge exposure following arrival in the enzootic zone, after which a transient increase in Anaplasma parasitemia, accompanied by a decrease in packed cell volume, occurred in most of the vaccinated calves. Neither clinical anaplasmosis nor mortality due to the disease occurred in the immunized cattle. Of the non-vaccinated calves, 27 had signs of clinical anaplasmosis and 5 (17%) died of the disease.