The material causing the blockage is normally foodstuff, but in isolated cases may consist of plastic, rocks, timber or other foreign materials. The blockage may be partial or complete. In most cases, choke is not an immediate emergency, but if the problem does not resolve quickly, then horses can become dehydrated, and the oesophagus can become irreversibly damaged. There is also a risk of the horse developing pneumonia. In severe cases, the condition can be life threatening.
Signs of choke
Horses with oesophageal obstruction generally drool saliva and food material. There is often also saliva and food discharging from both nostrils. If the horse attempts to eat or drink, the horse will cough or gag, and material will flow from the nostrils. The horse may make repeated attempts to swallow, bending and stretching out their neck and extending the head to try to clear the blockage. Many horses will also yawn repeatedly. Some horses will panic and be very agitated, or even show signs of colic.
In some instances, depending on where the obstruction has lodged, a lump may be seen on the left side of the neck, as this is where the oesophagus is situated.
If the horse has been choking for some time, it may be also severely depressed due to dehydration, due to the inability to swallow.
If you suspect your horse has choke:
Remove all food and water, and observe your horse closely. Keep the horse as calm as possible. In some cases, the continual production of saliva lubricates the obstruction, and it will break down and pass into the stomach without any necessary intervention.
If your horse is distressed, or depressed, or if you do not know how long the horse has been choking, then veterinary attention should be sought immediately. Any horse who has been choking for longer than 10 minutes should be seen by a veterinarian.
Treatment of Choke:
The veterinarian will examine your horse to determine the diagnosis. A nasogastric tube will be passed to confirm the diagnosis.
In simple cases, administration of some sedation will allow the oesophagus to relax and dilate, and the obstruction will pass.
In more severe cases, the vet will pass a stomach tube through the nostril into the oesophagus. The combination of gentle pressure and flushing can move the blockage through into the stomach.
If the blockage in the oesophagus is severe, or the horse has been choking for a long period of time, then surgical intervention may be indicated.
If your horse has become dehydrated, then rehydration therapy will be given. This may be as simple as oral administration of electrolytes, or if the horse is severely affected, intravenous fluids may be required.
Once the obstruction has been cleared, an endoscope may be used to examine the oesophagus to assess if any damage has been caused by the choking episode. This helps to determine what follow up care is needed, and will indicate if there are likely to be any long term problems.
After the obstruction is cleared, it is important to feed only soft foods for the next few days, such as green pasture or sloppy feeds while any local swelling is subsiding. The horse should also be monitored closely for any signs of infection. Checking the temperature twice daily for the next week is ideal.
Be sure to follow any instructions or recommendations that your veterinarian may give.
Possible complications of choke:
Permanent damage to the oesophageal wall may occur if the blockage is present for too long. Pressure on the wall of the oesophagus damages the blood supply and the wall structure. This may lead to the formation of ulcers, or damage to the underlying muscle layers.
If significant oesophageal damage occurs, the formation of a stricture may result. In the most severe cases, this may lead to oesophageal rupture, infection and death. The rupture may occur due to the obstruction causing damage to the oesophageal wall, or during attempts to dislodge the obstruction. Fortunately, this is uncommon.
In all instances of choke, there is a risk of aspiration (breathing in) of material into the respiratory system, due to the inability to swallow. This can lead to the development of severe pneumonia. The signs of aspiration pneumonia are generally not evident for 24 to 48 hours after a choking episode.
Irritation of the nasal tissues occurs due to the discharge of the overflow of food and saliva through the nostrils.
Prevention of choke:
As with all horse related problems, prevention is far more desirable than cure! Any condition which interferes with a horse’s ability to swallow normally may lead to the development of choke. This includes sedation, trauma to the neck or throat, and illness. Narrowing of the oesophagus may make a horse more prone to choke.
The most common cause of choke is food material that is not properly masticated (chewed) prior to swallowing. The primary cause of not chewing properly is dental disease.
Ensure that your horse has regular visits from an equine dental vet to ensure that their teeth are in optimal condition. Sharp, damaged or missing teeth will have a substantial impact on your horse’s general health, and contribute to the incidence of choke.
The second most common cause is eating too rapidly. Aggressive eaters need to be slowed down, for example by providing hay in bags with small openings, or placing the hay inside two haynets. This will help prevent cases where horses choke on hay by ensuring that the horse has to nibble at the hay and is unable to take large mouthfulls. Soaking hay prior to feeding also helps to prevent choke.
Feeding hay prior to concentrates may slow down horses that are aggressive with their hard feed, as they will already be partially full.
Feeding concentrates in large shallow feeders containing several large stones or salt blocks can prevent horses from taking large mouthfulls of hard feed, as they need to nibble in around the blocks. Alternatively, feeders with mesh over the feed can be used.
Wetting feed will also help avoid potential choke, and does not affect the nutrient content. Wet feeds will spoil more rapidly, particularly in warm climates, and it is important to discard any uneaten portion.
If you are feeding feeds which are designed to be soaked prior to feeding, ensure that the manufacturer’s directions are properly followed, or the feed may continue to swell once it is eaten, and this may contribute to choke.
In some cases, feeding the aggressive eater away from the herd will encourage them to eat more slowly due to reduced competition.
Some horses will choke repeatedly when given particular foods. In these cases, prevention is as simple as removing that food from the diet.
Treats such as carrots and apples should be cut into thin sticks rather than solid blocks, as these are less likely to cause obstruction.
Always ensure that there is plenty of fresh water available for your horse. Dehydration can contribute to choke occurring.