Multiple apparent Sarcocystis abortion in four bovine herds.

Foetuses recovered from multiple abortions in four dairy herds had multifocal nonsuppurative encephalitis, myocarditis and hepatitis. Focal placentitis was usually present. Sarcocystis-like protozoa were found in the brains of foetuses from two of the outbreaks. Apart from excess salivation in a few cows in one herd, farmers reported no clinical abnormalities prior to the abortions, and all cows remained normal after the abortions. Dogs and cats fed an affected foetus and neonatal calves from the affected herds failed to excrete protozoa in their faeces. The identity of the protozoa in the foetal brain was not confirmed.