First, in answer to the question, “Can horses throw up?” NO, they cannot throw up. But did you ever wonder why? Well our team at the University of Alberta has researched this question and came up with a detailed response.
When a horse first ingests food, it is swallowed through the mouth cavity and is passed down the esophagus. Horses have a strong band of muscle around their esophagus at the entrance to the stomach, called the “cardiac sphincter” also referred to as the “esophageal sphincter”. The cardiac sphincter is actually the strongest sphincter muscle of all species. The cardiac sphincter exists in all mammals at the top of the stomach, and in the horses it differs from other mammals because of its extreme strength and inability to relax and allow the horse to throw up like other mammals. As stated by Dr. Susan Novak, the AAFRD(Alberta Agriculture Food and Rural Development) Provincial Horse Specialist, “The horse is not able to throw up because the cardiac sphincter connecting the esophagus and stomach is so strong, that food is only allowed to go in one direction: Down! The horse is adapted to eating small frequent meals, and therefore the sphincters work to keep the feed moving constantly along the digestive tract.”
It seems the horse is at an advantage because it cannot throw up. First, the stomach of the equine species is very acidic like any other species. Second, this action of the cardiac sphincter and the pyloric sphincter at the exiting end of the stomach allow for the continual movement of the digestive system in the right direction, and prevent any backups, which could be very detrimental to the horse, causing conditions including colic. Horses are very instinctive and will usually avoid harmful feed that could cause them to become ill.
Since it is impossible for a horse to throw up, there is no way for anything to escape the stomach. As stated by Dr. Lana Bissett, from the Edmonton Equine Veterinary Services, “Cases of horses having spontaneous reflux is uncommon.” Based on the anatomy of the cardiac sphincter it will rarely release and because it so strong that the stomach lining will rupture before the sphincter gives way. This is a bad situation for horses and after the stomach has ruptured the horse will die.
There is something you can do for a horse once you’ve noticed that it’s showing colicky symptoms. But the procedure must be done quickly before the stomach lining ruptures. The procedure is known as tubing. A trained veterinarian must be contacted to tube the horse, and should not be attempted by the owner, because it is very easy to make a mistake. The vet will pass a tube (stiff with a bulb on the end) nasogastrically (through the nose) down the esophagus, and pass it through the cardiac sphincter, as stated by Dr. Lana Bissett, “Tubing, works well as it forces the sphincter open which releases the pressured contents, usually gases and sometimes fluids will be released right away or after gentle siphoning. Recovery is usually favorable (depending on the condition).”
- Shanna Hlady, Melissa Kozakewich and Lindsay Paulsen