Zinc Absorption from the Small Intestine in Young Calves

Zinc-65 was injected directly into various sites throughout the small intestine of Holstein calves fed a low zinc diet. Zinc absorption was determined by comparing zinc-65 content of blood, liver, kidney, lung, heart, pancreas, rib, muscle, and other tissues. Tissue zinc-65 was plotted against site of injection expressed as percentage of intestinal length from proximal to distal ends. Zinc absorption occurred throughout the small intestine with the amount absorbed per centimeter of length about equal throughout the small intestine. This is in contrast to conclusions from studies of rats indicating more absorption in the proximal part of the small intestine. The difference appears to have been due to artifacts in the procedures with rats. However, species and dietary differences may have affected relative findings between this and earlier work.