Psoroptic mites, thought to be Psoroptes ovis (Hering) and collected from bighorn sheep (Ovis canadensis mexicana) in southern New Mexico, were transferred to domestic sheep, rabbits and cattle. These mites established infestations in the ears of 5 of 6 rabbits but failed to establish lasting infestations on sheep. Reproducing colonies of mites were established with difficulty on cattle (3 of 11). The studies indicate that these mites are not adapted to cattle or domestic sheep.