The Site of Calcium Absorption in the Horse

Abstract
The site of calcium absorption in the horse was studied by the following techniques: 1) comparison of the degree of absorption of 47Ca deposited directly in a fistulated cecum versus that absorbed from an intragastric dose; 2) estimating apparent absorption in various regions of the intestinal tract, using Cr2O3 as an unabsorbable marker; 3) comparison of the degree of absorption of 47Ca from in vivo intestinal sacs of duodenum, ileum, cecum and colon. The upper part of the small intestine appeared to have the greatest calcium absorptive potential and to be the major effective site of net calcium absorption. However, the lower portion of the small intestine may also be a site of significant calcium absorption. Relatively little calcium was absorbed from the large intestine.