Eimeria tenella: experimental studies on the development of resistance to halofuginone

Resistance to halofuginone has been developed by serially passaging the Houghton strain of Eimeria tenella in chickens medicated with progressively greater concentrations of drug. Attempts to develop resistance to 3 ppm (as recommended for use by the manufacturer) or higher concentrations, by the method of Weppelman et al., were unsuccessful.