Resistance to experimental infection with Fasciola hepatica in exotic and domestic breeds of sheep

Abstract Significant breed differences were detected in fecal egg counts and fluke counts following experimental infection of five breeds of sheep with metacercariae of F. hepatica . Two experiments compared the responses of Barbados Blackbelly, St. Croix, Florida Native, Finn X Rambouillet and Targhee sheep to primary and challenge infections (Expt. 1) and to multiple infections (Expt. 2). Barbados Blackbelly sheep were more susceptible to infection than the other breeds in both experiments. St. Croix and Florida Native sheep were the most resistant breeds in Expt. 1, while Targhee and Florida Native were the most resistant in Expt. 2. There was no evidence of acquired immunity in any breed in either experiment.