The site of calcium absorption in the horse.

The research study investigated where calcium is absorbed in the horse’s body. It was found that the upper part of the small intestine demonstrates the highest calcium absorption potential, while a significant amount of calcium may also be absorbed from the lower portion of the small intestine. The large intestine demonstrated relatively little calcium absorption.

Study Methods

• The researchers used several techniques to identify the site of calcium absorption in horses:
  • They compared the absorption of calcium-47 (47Ca), a radioactive isotope of calcium, when it was directly deposited into a fistulated cecum versus when it was ingested.
  • They estimated apparent absorption in various regions of the intestinal tract, using chromium oxide (Cr2O3) as an unabsorbable marker. This strategy allows researchers to trace the path of the monitored substance (in this case, calcium) and identify where it is absorbed.
  • They compared the degree of absorption of 47Ca from in vivo intestinal sacs of different parts of the intestine, namely the duodenum, ileum, cecum, and colon.

Major Findings

• From these experiments, the researchers concluded that the upper part of the small intestine showed the greatest calcium absorptive potential, making it the primary site for calcium absorption in horses.
• The small intestine’s lower portion was also identified as a location where significant calcium absorption can occur.
• Contrarily, the large intestine was found to absorb relatively little calcium.

Significance of the Study

• These findings are important because they shed light on the physiology of calcium absorption in horses.
• Such information can potentially inform dietary interventions or medical treatments for horses with nutritional deficiencies or metabolic disorders related to calcium.