Could treatment of pregnant mares prevent abortions due to equine piroplasmosis?

Treatment of pregnant mares to prevent abortions due to equine piroplasmosi s is a novel idea practised empirically at some Thoroughbred studs in South Africa. This paper presents the results of an investigation to ascertain w hether imidocarb dipropionate crosses the equine placenta. Three pregnant m ares were injected intramuscularly with imidocarb and their foetuses were m echanically aborted at varying time intervals thereafter. Imidocarb was fou nd in foetal blood at a level similar to that in the dam's blood, suggestin g that imidocarb administered to the dam would be available for anti-parasi tic activity in the foetal circulation. Uncertainty concerning the time of treatment to achieve the desired effect currently makes this a questionable exercise.