The effect of picolinic acid and hydroxyquinolines in intestinal zinc absorption of cattle was studied. In contrast to reports of the absorption in rat and in man, picolinic acid did not enhance zinc absorption in cattle. In two calves suffering from Adema disease, the bovine parallel to Acrodermatitis enteropathica, hydroxyquinoline supplementation resulted in an increase in intestinal 65Zn absorption, while picolinic acid had no such effect. The results may indicate a difference in the zinc absorption mechanism between cattle and other species.