Atresia Ani Atresia Ani is a rare condition that causes foals to be born without an anus. It also may cause part or all the rectum to be missing. Surgery is the only option for foals born with this devastating condition. Symptoms and Types Foals with this condition display signs such as:
- Colic-like symptoms (e.g., abdominal pain)
- Straining to pass a bowel movement
- Swelling of space where anus should be (if rectum intact)
Causes Nobody knows what causes atresia ani in horses.