Effects of age, sex, and post mortem interval on intestinal lengths of horses during development.

Lengths of small intestine, caecum, ascending colon and descending colon were measured in intestinal tracts from 103 foetuses, foals and adult horses. Intestinal tracts from 21 of the horses were measured at varying intervals after death. Total intestinal length increased markedly from mid-gestation to one year of age, then showed little increment up to 35 years. Small intestinal length increased most rapidly in the first month of life. Caecal length increased most rapidly from one to six months and length of ascending colon increased most rapidly between one week and one year. Descending colon length increased gradually after birth. Periods of rapid increase in length of various intestinal segments and alterations in the percentage of total intestinal length were associated with periods of rapid body growth and changes in dietary composition. Sex and post mortem interval did not affect intestinal length significantly.