Large colon resection.

With large colon resection and anastomosis, up to 95 per cent of the length of the large colon has been successfully removed. A hand-sewn end-to-end anastomosis is effective for lesions in the left dorsal colon and pelvic flexure. Transection and a side-to-side anastomosis with stapling equipment is most effective for extensive resections (greater than 50 per cent). Horses with extensive colon resection (95 per cent) have permanent deficiencies of water absorption and digestion of cellulose and protein. Fermentative capacity is reduced, owing to decreased particulate matter retention time in the smaller capacity colon. These deficits are minimized with alfalfa hay as the source of forage (fed at 2 per cent of the body weight), and normal blood variables and body weight can be maintained. Voluntary intake increases to help maintain a positive nutrient balance. Grass hay, owing to the higher cell wall content, is inadequate as the sole source of energy and protein, and weight loss will occur. Ad libitum intake of water is recommended at all times, owing to the increased fecal water loss.