by Naomi Barrett
It can be extremely alarming to find your horse coughing and gagging with food material and saliva pouring out of their nose and mouth. This is a classic sign of the relatively common condition known as ‘choke’, which occurs when something (usually food) obstructs the horse’s oesophagus. The presence of an obstruction triggers the oesophageal muscles to spasm causing the offending item to become more firmly wedged in place, triggering further spasm and exacerbating the situation further. The passage of any more food, saliva or fluid is inhibited by the blockage, which means that any such material ends up being forced back out of the horses’ nose or mouth as the horse tries to clear the problem.
Choke frequently happens as a result of horses not chewing their food properly, which means that greedy horses that bolt their food are at high risk. Anything that might prevent a horse from properly grinding up their food is also likely to predispose them to choke, including dental problems such as sharp points on teeth or loose or missing teeth. Another risk factor is any food that is too coarse or dry or one that swells rapidly after eating (e.g. sugar beet) and may become lodged in the oesophagus. Chunks of hard vegetables or fruit (e.g. carrots or apples) of an inappropriate size that are not chewed sufficiently can easily become stuck as well. Conditions that interfere with the ability to swallow (e.g. sedation, neck/oesophageal injuries, botulism and grass sickness) or that result in narrowing of the oesophagus (e.g. abscesses, strictures or tumours) also increase the likelihood of choke. A less common cause of choke may be if a horse ingests an inedible foreign body such as a piece of wood (a small but potential risk for crib biters).
Discharge from the nose and/or mouth, which is typically green due to food material but may be yellow or clear, is the most instantly recognisable indicator of choke. The horse may also extend their head downwards and cough and gag repeatedly in an attempt to clear the obstruction. They may become quite distressed and even start demonstrating signs of colic such as getting up and down and rolling. They will have apparent difficulty in swallowing. Sometimes it is possible to palpate or even see the cause of the obstruction as a lump on the side of the neck. As the condition progresses or if it remains unnoticed the horse will become increasingly depressed and also dehydrated due to being unable to swallow any water. Complications can develop, such as inhalation pneumonia due to the material brought up into the back of the horse’s throat being breathed into the windpipe. The worst case scenario would involve oesophageal rupture due to the tissue around the blockage dying off, potentially leading to death due to shock and infection. Fortunately, this is extremely uncommon.
Choke can easily be diagnosed by a veterinary surgeon passing a stomach tube through a nostril into the oesophagus to determine whether there is a blockage. Being entirely unable to reach the level of the stomach suggests a complete obstruction, whilst difficulty passing the tube indicate only partial obstruction or possibly a narrowing of the oesophagus. The tube may also be used to ascertain at what level the blockage has occurred and how firmly lodged it is. Gentle pressure may be applied to try and push the offending item down into the stomach.
Many cases of choke resolve on their own as the copious amount of saliva the horse produces lubricates the obstruction until it can pass into the stomach. It is advisable to remove all food, water and edible bedding until this has occurred. Keeping the horse’s head low and massaging any palpable lumps on the left side of the neck is helpful. A vet can give a sedative to help keep the head low and a spasmolytic to relax the muscles of the oesophagus to try and speed this process up. For some situations (i.e. where the horse continues choking for over 24 hours) this is clearly not enough, in which case a stomach tube may be passed and flushed with water to soften and lubricate the obstructive material enabling its’ passage down to the stomach. This must be done with great care to avoid damaging the oesophagus and therefore can take some time (up to days), particularly if there is a lot of material contributing to the blockage. Once the oesophagus is clear again anti-inflammatories and antibiotics may be required to try and prevent oesophageal scarring which could lead to a recurrence and to reduce the risk of inhalation pneumonia. It is strongly recommended to give wet, sloppy feeds for several days afterwards to enable time for any swelling to reduce. Prevention: Preventing choke simply involves minimising the risk factors that predispose a horse to the condition. This includes soaking dry feeds (especially ones prone to swelling such as sugar beet pulp), chopping carrots and apples lengthways so they are chewed properly and ensuring a good supply of water at all times. Feeding away from other horses may stop them bolting their food or if this persists using a device like a feed ball can help slow things down. Meanwhile, yearly dental checks will help keep on top of any teeth problems. Choke is a condition that can be equally distressing for both horse and owner. It is important to remember that most cases will resolve quite rapidly on their own; however due to the potential complications that choke can cause, it is definitely worth contacting a veterinary surgeon for advice.If you have any questions about any aspects of your horse’s health, or indeed your pet, farm or smallholding animals, please do not hesitate to contact us on 01892 835456. Putlands Veterinary Surgery is based in Paddock Wood in Kent, and offers a friendly, professional and personal service for all species of animal. We have four dedicated large animal vets with a wealth of equine experience between us, and are always happy to help.