The ferromagnetic YCo3 compound exhibits two successive field-induced itinerant metamagnetic transitions from the low magnetic moment state to higher ones at 60 and 82 T. These transitions can also be induced by the substitution of Fe for Co in YCo3. The observed anomalous magnetic behavior can satisfactorily be explained in terms of the occurrence of two successive metamagnetic transitions on three different non-equivalent Co sites with different local anisotropies in sign and value.