Understanding Choke in Horses

Lillian M.B. Haywood, VMD, CVMA
Edits and contributions made by: Kimberly Allshouse, DVM 

 Esophageal obstruction, or “choke,” is a common equine emergency. Unlike in human medicine, where choking refers to a tracheal (or windpipe) obstruction, choke in horses refers to an obstruction of the esophagus, the muscular tube that carries food from the mouth to the stomach. The most common sign of choke that horse owners recognize is feed material coming from the nostrils, although you might also notice hypersalivating, retching, not eating, or coughing.  Choking horses may also present with colicky behaviors such as pawing or rolling. Choke episodes can have serious consequences, so it is important to have your veterinarian evaluate your horse as soon as possible.   

 Most commonly, chokes occur when horses eat concentrated feed too quickly without chewing it appropriately. The feed does not get softened with saliva and forms a firm bolus that gets lodged in the esophagus. Some feeds such as hay cubes, hay stretcher, or beet pulp, should be soaked before feeding to reduce the likelihood of choke. Esophageal obstruction can also occur with hay or straw, hard treats, carrots, or nonfood objects. Oral pathology such as occlusal abnormalities, endodontic, or periodontic disease can significantly increases your horse’s likelihood of choke. Anatomical problems, such as abnormal esophagus anatomy, can also predispose a horse to choking.  One example of this is stricture, or narrowing, of a segment of the esophagus.  

 While waiting for the veterinarian, it is important that you keep your horse from eating or drinking. Hand-walking or muzzling can prevent continued feed intake. Also, do not administer oral medications. While the horse is choking, anything it tries to swallow can potentially go down the airway to the lungs.  It is an old wives’ tale that you can and should resolve a choke by placing a garden hose in your horse’s mouth – this is NOT recommended! This practice only increases the risk of serious complications, especially aspiration pneumonia.   

 Upon arriving, your veterinarian will conduct a physical exam.  Some choking horses are sensitive to esophageal palpation, and in some cases the obstruction can be visible on the left side of the horse’s neck. However, if a horse has continued to eat after choking, it can result in distention of the entire esophagus rather than apparent focal swelling. A severe choke is typically obvious to both veterinarians and horse owners, but a mild choke could be confused with an upper respiratory tract infection or colic.   

 There are two main schools of thought on treating equine esophageal obstruction. The first and most common approach is to sedate the horse and pass a nasogastric tube to clear the obstruction. The veterinarian lavages (flushes) the obstruction with small volumes of water and slowly removes the accumulated feed material. It is important to do this gently to prevent esophageal rupture or inadvertent aspiration.  The second approach is based on the theory that many chokes eventually self-cure, so veterinarians might administer repeated rounds of sedation, medications to relax the esophageal muscles, and intravenous fluids to keep the horse hydrated while waiting for the obstruction to resolve.   

 Rarely, veterinarians are unable to resolve a choke using nasogastric intubation. In those cases, you might need to send your horse to a referral center for further diagnostics, such as an endoscopic examination. The veterinarian can use the endoscope – a tiny camera passed down the esophagus – to identify the type of object causing the obstruction.  This is especially important if the obstruction is a solid object that will not readily resolve with flushing, such as a foreign body or a piece of carrot. Endoscopy can also help the veterinarian diagnose any anatomical abnormalities of the esophagus.   

 Following resolution of the obstruction, the horse will need continued care. Most importantly, chokes predispose horses to aspiration pneumonia, which is caused by fluid and feed material going down the trachea and into the lungs. This foreign material in the lungs can cause the horse to develop a secondary bacterial infection. To prevent this, many veterinarians place horses on prophylactic antibiotics following an episode of choke. It is important to monitor the horse’s temperature following a choking episode because a fever might be one of the first signs of pneumonia. Other signs of pneumonia include coughing, nasal discharge, and increased respiratory rate or effort. Your veterinarian might also administer sucralfate, a medication to help treat ulceration of the esophagus, or a non-steroidal anti-inflammatory drug (NSAID) such as flunixin meglumine (Banamine).  You should always check a horse’s temperature before administering NSAIDs, as these medications will mask a fever.   

 Depending on the severity of the choke, you might need to withhold certain types of feed for several days. Typically, it is recommended to avoid dry feeds and hay, and instead offer the horse a soupy mash of complete concentrate feed. Horses who repeatedly choke might need to remain on soupy mashes indefinitely.  Horses who choke on hay may need to eat soaked hay cubes or soaked hay pellets instead of long stem forage.  Horses that eat too quickly sometimes benefit from having large, smooth rocks placed in their feed tubs. Finally, as mentioned above, a common cause of choke is poor dentition leading to inadequate chewing; be sure to schedule a thorough oral exam with your veterinarian following a choking episode. Additional diagnostics such as an endoscopic exam of the guttural pouches, upper airway, and esophagus may also be recommended.  

 Chokes are common equine emergencies with potentially serious consequences. Call your veterinarian as soon as you notice signs of choke.   

Article provided by AAEP Media Partner, The Horse.