RESUMO
The receptivity and susceptibility of the Muscovy duck, the domestic duck, and their hybrid, the mule duck, toward an experimental infection by Eimeria mulardi were studied. To appraise their susceptibility, female ducklings were infected with a dose of 75,000 oocysts per duckling (bringing about a clinical coccidiosis). In another group, to compare the multiplication rates of the parasite in the three species of ducks, thus assessing their receptivity, an infection with 750 oocysts per duckling was realized. Eimeria mulardi develops in the three species of ducks. In each case, a significant decrease in growth in the contaminated group vs. the control group was noted, even though the Muscovy and the mule ducks were more susceptible to the contamination.