Choke (horse)

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Choke is a condition in horses in which the esophagus is blocked, usually by food material. Although the horse is still able to breathe, it is unable to swallow, and may become severely dehydrated. A secondary condition, aspiration pneumonia, may also develop if food material and saliva accumulate in the pharynx, spilling into the trachea and into the lungs. Choke is one of the "top 10" emergencies received by equine veterinarians. [1]

Contents

The condition is seen in other Equidae like mules and donkeys.

Causes

Chewing: Horses may develop choke if they do not chew their food properly. Therefore, horses with dental problems (e.g. acquired or congenital malocclusion, loose or missing teeth, or excessively sharp dental ridges) that do not allow them to completely grind their food are particularly at risk. [2] [3] In addition, horses that bolt their feed and do not take the time to chew properly are more likely to suffer from choke. [4] [5]

Dry Food: Dry foods may cause choke, especially if the horse does not have free access to water, or if the horse has other risk factors linked to choking. [4] While pelleted or cubed feeds in general fall in this category, horse owners sometimes express particular concerns about beet pulp. However, while horses have choked on beet pulp, a university study did not document that beet pulp is a particular problem. [4] It is believed that choke related to beet pulp is linked to the particle size and the horse's aggressive feeding behaviour, rather than the actual feed itself. [5] Research suggests that horses that bolt their feed without sufficient chewing, or who do not have adequate access to water, are far more likely to choke, regardless of the type of feed, compared to horses that eat at a more leisurely rate. [5] The risk of choke associated with any dry feed can be reduced by soaking the ration prior to feeding. [4]

Foreign Objects: Horse may ingest non-edible materials such as pieces of wood. Cribbers may be more prone to this type of choke, if they happen to swallow a piece of wood or other material while cribbing.

Signs of choke

Discharge of the nostrils in a donkey with choke due to eating dry sugar beet pulps 3 days ago; note enlarged esophagus in the shaved area Agne tchocaedje di l' avala rinadaedje narenes.JPG
Discharge of the nostrils in a donkey with choke due to eating dry sugar beet pulps 3 days ago; note enlarged esophagus in the shaved area

Diagnosing choke

If a horse is suspected of choke, a veterinarian will often pass a stomach tube down the animal's esophagus to determine if there is a blockage. Failure to access the stomach with the tube indicates a complete obstruction; difficulty passing the tube may represent a stenosis, or narrowing; or a partial obstruction. Radiography and endoscopy are also used in refractory cases.

Treatment

surgery of choke in a donkey: in opened esophagus, note reflux of sugar beet pulps Agne operacion tchocaedje di l' avala buzea drovou pules.JPG
surgery of choke in a donkey: in opened esophagus, note reflux of sugar beet pulps

Choking horses should be deprived of food and drink pending veterinary attention, so as not to increase the obstructive load within the esophagus. The veterinarian will often sedate the horse and administer spasmolytics, such as butylscopolamine, to help the esophagus to relax. Once the muscles of the esophagus no longer force the food down the throat (active peristalsis), it may slip down on its own accord. If spasmolytics do not solve the problem, the veterinarian will usually pass a stomach tube through one of the nostrils and direct it into the esophagus until the material is reached, at which point gentle pressure is applied to manually push the material down. Gentle warm water lavage (water sent through the stomach tube, to soften the food material) may be required to help the obstructing matter pass more easily, but caution should be exercised to prevent further aspiration of fluid into the trachea.

Refractory cases are sometimes anesthetised, with an orotracheal tube placed to prevent further aspiration and to allow for more vigorous lavage. Disruption of the impacted material can sometimes be achieved via endoscopy. If these methods still do not lead to results, the horse may require surgery to remove the material. Some workers have advocated the use of oxytocin in choke, on the grounds that it decreases the esophageal muscular tone. [6] However, this technique is not suitable in pregnant mares, as it may lead to abortion.

Following up

After the material has passed, a veterinarian may try to prevent the onset of aspiration pneumonia by placing the horse on broad-spectrum antibiotics. The animal should be monitored for several days to ensure that it does not develop pneumonia, caused by inhalation of bacteria-rich food material into the lungs.

The material caught in a horse's throat usually causes inflammation, which may later lead to scarring. Scarring reduces the diameter of the esophagus (a stenosis or stricture), which increases the chance that the horse may choke again. The veterinarian may therefore place the horse on a course of NSAIDs, to help to control the inflammation of the esophagus.

Often the horse will only be fed softened food for a few days, allowing the esophagus to heal, before it is allowed to gradually resume its normal diet (e.g. hay and unsoaked grain). Horses with re-occurring chokes may require their diet to be changed.

Prevention

Related Research Articles

Horse teeth

Horse teeth refers to the dentition of equine species, including horses and donkeys. Equines are both heterodontous and diphyodontous, which means that they have teeth in more than one shape, and have two successive sets of teeth, the deciduous and permanent sets.

Esophagus Vertebrate organ through which food passes to the stomach


The esophagus, or oesophagus, informally known as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the stomach. The esophagus is a fibromuscular tube, about 25 cm (10 in) long in adults, which travels behind the trachea and heart, passes through the diaphragm and empties into the uppermost region of the stomach. During swallowing, the epiglottis tilts backwards to prevent food from going down the larynx and lungs. The word oesophagus is the Greek word οἰσοφάγος oisophagos, meaning "gullet".

Esophageal atresia Congenital discontinuity of the oesophagus

Esophageal atresia is a congenital medical condition that affects the alimentary tract. It causes the esophagus to end in a blind-ended pouch rather than connecting normally to the stomach. It comprises a variety of congenital anatomic defects that are caused by an abnormal embryological development of the esophagus. It is characterized anatomically by a congenital obstruction of the esophagus with interruption of the continuity of the esophageal wall.

Dysphagia is difficulty in swallowing. Although classified under "symptoms and signs" in ICD-10, in some contexts it is classified as a condition in its own right.

Nasogastric intubation insertion of a plastic tube through the nose, past the throat, and down into the stomach

Nasogastric intubation is a medical process involving the insertion of a plastic tube through the nose, past the throat, and down into the stomach. Orogastric intubation is a similar process involving the insertion of a plastic tube through the mouth. Abraham Louis Levin invented the NG tube.

Pulmonary aspiration Entry of materials into the larynx (voice box) and lower respiratory tract

Pulmonary aspiration is the entry of material such as pharyngeal secretions, food or drink, or stomach contents from the oropharynx or gastrointestinal tract, into the larynx and lower respiratory tract, the portions of the respiratory system from the trachea (windpipe) to the lungs. A person may inhale the material, or it may be delivered into the tracheobronchial tree during positive pressure ventilation. When pulmonary aspiration occurs during eating and drinking, the aspirated material is often colloquially referred to as "going down the wrong pipe."

Epiglottis Leaf-shaped flap in the throat that prevents food from entering the windpipe and the lungs

The epiglottis is a leaf-shaped flap in the throat that prevents food from entering the windpipe and the lungs. It stands open during breathing, allowing air into the larynx. During swallowing, it closes to prevent aspiration of food into the lungs, forcing the swallowed liquids or food to go along the esophagus toward the stomach instead. It is thus the valve that diverts passage to either the trachea or the esophagus.

Feeding tube type of medical device used for people who are unable to obtain nutrition because of difficulty swallowing

A feeding tube is a medical device used to provide nutrition to people who cannot obtain nutrition by mouth, are unable to swallow safely, or need nutritional supplementation. The state of being fed by a feeding tube is called gavage, enteral feeding or tube feeding. Placement may be temporary for the treatment of acute conditions or lifelong in the case of chronic disabilities. A variety of feeding tubes are used in medical practice. They are usually made of polyurethane or silicone. The diameter of a feeding tube is measured in French units. They are classified by the site of insertion and intended use.

Esophagogastroduodenoscopy a diagnostic endoscopic procedure that visualizes the upper part of the gastrointestinal tract down to the duodenum

Esophagogastroduodenoscopy, also called by various other names, is a diagnostic endoscopic procedure that visualizes the upper part of the gastrointestinal tract down to the duodenum. It is considered a minimally invasive procedure since it does not require an incision into one of the major body cavities and does not require any significant recovery after the procedure. However, a sore throat is common.

Megaesophagus abnormal dilation of the esophagus not due to obstruction

Megaesophagus, also known as esophageal dilatation, is a disorder of the esophagus in humans and other mammals, whereby the esophagus becomes abnormally enlarged. Megaesophagus may be caused by any disease which causes the muscles of the esophagus to fail to properly propel food and liquid from the mouth into the stomach. Food can become lodged in the flaccid esophagus, where it may decay, be regurgitated, or may be inhaled into the lungs.

Colic in horses is defined as abdominal pain, but it is a clinical symptom rather than a diagnosis. The term colic can encompass all forms of gastrointestinal conditions which cause pain as well as other causes of abdominal pain not involving the gastrointestinal tract. The most common forms of colic are gastrointestinal in nature and are most often related to colonic disturbance. There are a variety of different causes of colic, some of which can prove fatal without surgical intervention. Colic surgery is usually an expensive procedure as it is major abdominal surgery, often with intensive aftercare. Among domesticated horses, colic is the leading cause of premature death. The incidence of colic in the general horse population has been estimated between 4 and 10 percent over the course of the average lifespan. Clinical signs of colic generally require treatment by a veterinarian. The conditions that cause colic can become life-threatening in a short period of time.

Aspiration pneumonia bronchopneumonia that develops due to the entrance of foreign materials into the lungs

Aspiration pneumonia is a type of lung infection that is due to a relatively large amount of material from the stomach or mouth entering the lungs. Signs and symptoms often include fever and cough of relatively rapid onset. Complications may include lung abscess. Some include chemical induced inflammation of the lungs as a subtype, which occurs from acidic but non-infectious stomach contents entering the lungs.

Oropharyngeal dysphagia arises from abnormalities of muscles, nerves or structures of the oral cavity, pharynx, and upper esophageal sphincter.

Schatzki ring congenital disorder of digestive system

A Schatzki ring or Schatzki–Gary ring is a narrowing of the lower esophagus that can cause difficulty swallowing (dysphagia). The narrowing is caused by a ring of mucosal tissue or muscular tissue. A Schatzki ring is a specific type of "esophageal ring", and Schatzki rings are further subdivided into those above the esophagus/stomach junction, and those found at the squamocolumnar junction in the lower esophagus.

Equine nutrition

Equine nutrition is the feeding of horses, ponies, mules, donkeys, and other equines. Correct and balanced nutrition is a critical component of proper horse care.

Beet pulp byproduct of beet processing used as fodder for livestock

Beet pulp is a byproduct from the processing of sugar beet which is used as fodder for horses and other livestock. Beet pulp is the fibrous material left over after the sugar is extracted from sugar beets. It is supplied either as dried flakes or as compressed pellets, but when fed to horses it should always be soaked in water first.

Hard keeper

A hard keeper or poor doer is a horse or other livestock animal that is naturally prone to be thin, will lose weight quickly, and has difficulty gaining weight.

Esophageal food bolus obstruction medical emergency caused by the obstruction of the esophagus by an ingested foreign body

An esophageal food bolus obstruction is a medical emergency caused by the obstruction of the esophagus by an ingested foreign body.

Foreign body aspiration

Foreign body aspiration occurs when a foreign body enters the airways and causes choking. Objects can enter the esophagus through the mouth, or enter the trachea through the mouth or nose.

Equine gastric ulcer syndrome (EGUS) is a common cause of colic and decreased performance in horses. Horses form ulcers in the mucosa of the stomach, leading to pain, decreased appetite, weight loss, and behavioral changes. Treatment generally involves reducing acid production of the stomach and dietary management. Unlike some animals, however, stomach rupture is rare, and the main goal of treating is to reduce pain and improve performance of animals used for showing or racing.

References

  1. ↑ Mississippi State University, CARES programme
  2. ↑ Ralston, SL (June 2005). "Feeding Dentally Challenged Horses". Clinical Techniques in Equine Practice. Elsevier. 4 (2): 117–119. doi:10.1053/j.ctep.2005.04.002.
  3. ↑ Ferraro, GL; Wilson WD; Basile T; Meierhenry BJ (April 2006). "Equine Dentistry: It's Not Just Floating Anymore" (PDF). The Horse Report. Centre for Equine Health, UC Davis School of Veterinary Medicine. 24 (2).[ permanent dead link ]
  4. 1 2 3 4 ""Should You Feed Beet Pulp?" Equus magazine, accessed via equisearch.com June 28, 2010". Archived from the original on May 15, 2009. Retrieved June 28, 2010.
  5. 1 2 3 Warren, Lori K. "Horse Feeding Myths and Misconceptions Archived January 25, 2010, at the Wayback Machine " Horse Industry Section, Alberta Agriculture, Food and Rural Development. Web site accessed June 28, 2010
  6. ↑ Meyer GA, Rashmir-Raven A, Helms RJ, Brashier M (2000). "The effect of oxytocin on contractility of the equine oesophagus: a potential treatment for oesophageal obstruction". Equine Vet. J. 32 (2): 151–5. doi:10.2746/042516400777591660. PMID   10743971.
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