Feeding the Choke-Prone Horse

To prevent esophageal obstruction, take a page from the scientific journals

Derby, your 15-year-old Thoroughbred, hasn’t finished his grain. A greenish nasal discharge and a large amount of saliva stream from his mouth. He also keeps extending his neck and coughing repeatedly, as if he’s trying to clear his throat. What’s going on here? 

Choke, or esophageal obstruction, occurs when food or foreign materials partially or completely block the esophagus. Choke might not be immediately life-threatening—he can still breathe—but it is distressing, will prevent your horse or pony from eating and drinking, and must be addressed by a veterinarian as soon as possible. In fact, many horses that have choked need to be on antibiotics to prevent or treat aspiration pneumonia, which can be deadly.

In this article, we will discuss which equid groups are at the highest risk for developing feed-related choke and suggest mealtime management techniques to help reduce those risks.

Causes of Choke

Esophageal obstruction occurs most commonly in horses and ponies that consume feed (forage or grain) very quickly without adequate mastication (chewing). In a 2010 article published in the Journal of Veterinary Internal Medicine, Chiavaccini and Hassel reported that causes of esophageal obstruction in horses include:

  • Ingesting inadequately soaked sugar beet pulp;
  • Ingesting apples or carrots;
  • Rapidly ingesting dry fibrous, pelleted, or cubed feedstuffs;
  • Inadequately masticating due to poor dentition; or
  • Swallowing a foreign object. 

Other reported causes include consuming grain or hay while under heavy sedation and not drinking enough water.

Let’s look at reasons these scenarios lead to choke.

Feed

What feed characteristics seem to cause horses to choke? Any sizable food items, such as apples, carrots, or large cubes, if swallowed whole, can easily lodge and get stuck in the esophagus.

Behavior

For an example of behavior-related choke, let’s take a look at a case study of a 5-year-old Thoroughbred gelding that arrived at South Eastern Equine Hospital, in Victoria, Australia, very early one Saturday morning. His owners had found him coughing, with food material and saliva streaming from his nostrils, which are classic signs of choke. The referring veterinarian attempted to relieve the obstruction by passing a tube up the horse’s nose to flush out his esophagus, but the feed material remained stuck and would not move down into the stomach.

More than likely, this horse ingested a large amount of a dry pelleted feed in a very short period. The feed type itself might not be to blame directly; ­aggressive eating behaviors, such as bolting, can cause a horse to choke on any feed. Ingesting large amounts of food, either pellets, sweet feed, or hay, without chewing adequately before swallowing, can result in insufficient saliva production to lubricate the feed. This makes travel down the esophagus into the stomach more difficult. Large group feeding situations increase the likelihood of these aggressive eating behaviors.

Dentition

Again, let’s look at a real-life example of a dentition-related choke case to better understand how it happens. A 30-year-old Quarter Horse mare in Florida arrived at a large animal clinic for choke treatment. The mare’s esophagus had been obstructed for approximately 12 hours and, despite multiple veterinarians’ best efforts on the farm, her condition was not improving.

Whether it’s the young horse with erupting teeth or a senior horse missing molars, poor or abnormal dentition greatly reduces the animal’s ability to break down feed and can lead to choke. If young horses rapidly consume large pellets or cubes intended for mature horses or dry stemmy hay, they’re more likely to choke. Esophageal obstruction tends to be a major concern when caring for older horses; an estimated 95% of horses older than 15 have dental ­abnormalities that preclude proper chewing (Ireland et al., 2012). 

If young or senior horses and ponies experience choke, they might be more likely to suffer other, more serious consequences. In a retrospective survey of 109 choke cases admitted to Colorado State University’s (CSU) Equine Hospital from April 1992 to February 2009, horses younger than 1 experiencing esophageal obstruction were 4.6 times more likely to develop aspiration pneumonia as a result, where food and saliva enter the trachea and cause infection. Horses older than 15 were 3.1 times more likely to develop aspiration pneumonia after choking (Chiavaccini and Hassel, 2010).

Feeding the Choke-Prone Horse

Feeding Choke-Prone Horses

Because, say CSU researchers, horses with a history of chronic obstruction are nine times more likely to develop complications such as aspiration pneumonia and tracheal contamination than unaffected horses, preventive feeding practices are very important for maintaining choke-prone horses’ health. Most choke cases can be directly related to rapid intake of either grain or hay. The first step in choke prevention? Identify high-risk individuals, such as older horses and those that bolt feed. Next, try implementing one or more of the following feeding strategies:

Soak feeds that commonly cause problems prior to feeding.

You can simply mix beet pulp, large cubes, or pelleted feeds with water immediately before mealtime to prevent rapid consumption. Usually, pellets or small cubes will absorb water quickly, within 5 to 10 minutes. Larger cubes and beet pulp need to be soaked for longer periods.

Feed hay before grain.

Feed hay before grain, or mix chaff or chopped hay in with the horse’s grain meal to slow consumption and encourage adequate chewing.

Slow grain consumption by altering the feed bucket.

Add potato-sized or larger smooth stones or blocks or even bocce-sized balls into the feed tub, suggest researchers at North Carolina State University. This team observed longer mealtimes when they placed a waffle-type plate at the bottom of the bucket (Kutzner-­Mulligan et al., 2013).

Researchers have also found that specialized feed tubs made to reduce consumption speed can extend feed consumption. In a study out of Texas A&M University, horses offered a ­pelleted feed in a feeder with molded cups on the bottom spent more time eating and dropped less feed than horses fed out of a rubber feed tub with no insert (Carter et al., 2012).

Feeding Choke-Prone Horses: Small-Hole Haynets

Use small-hole haynets to control the rate of hay consumption.

This not only prevents horses from taking large bites but also helps reduce feeding aggression. Feeding hay out of medium nets (those with 4.4-cm openings) and small nets (with 3.2-cm openings) reduced hay consumption rate and increased consumption time over feeding off the floor or from large (with 15.2-cm openings) nets (Glunk et al., 2014). At the Swiss Federal Institute of Technology, researchers observed less aggressive behavior when they fed hay in slow-feed haynets (TheHorse.com/149434).

When feeding in groups, offer smaller, more frequent meals or separate horses and ponies by barriers or distance.

Belgian researchers looking at feed aggression found that group-housed horses showed fewer aggressive ­behaviors (which, again, can cause horses to eat faster) when fed six times vs. three times per day (TheHorse.com/116567). In the aforementioned Swiss study, horses exhibited the fewest aggressive behaviors when hay was spaced at least 1 to 1.5 meters (3.2 to 4.9 feet) apart or when a physical barrier separated the horses.

Feeding the Choke-Prone Horse: Grazing Muzzles

Use a grazing muzzle when feeding.

Grazing muzzles have been proven to be an effective method for reducing pasture intake. Grazing muzzles significantly reduced ponies’ pasture consumption by about 85% compared to ponies not wearing muzzles (Longland et al., 2011). Another research group evaluated grazing muzzles as a way to slow pelleted feed consumption.

“The purpose of this work was to investigate safe and easy methods to slow consumption in horses that are very aggressive eaters,” says Erin Perry, PhD, assistant professor at Southern Illinois University, in Carbondale.

Perry’s team measured how quickly muzzled and nonmuzzled horses consumed 5 pounds of a commercial pelleted feed over 10 minutes. “We were able to reduce the rate of intake by using commonly available grazing muzzles,” she says. “For horses that are prone to choke because of aggressive eating, this may provide a method for getting them to slow down and chew their dinner—just like our mothers used to ask us to do.”

Post-Choke Meals

If, despite preventive approaches, your horse has a choke episode, it’s important to feed him properly afterward. “Typically I like to ‘rest’ the esophagus for a period of 12 hours or so if there was inflammation present at the site of obstruction (i.e., a long-standing choke),” says Diana Hassel, DVM, PhD, Dipl. ACVS, ACVECC, associate professor of equine emergency surgery and critical care at Colorado State University. “During this time I will put a horse in a rubber mat stall without bedding and only offer water if the obstruction has been relieved.”

When introducing food, Hassel and others recommend making a slurry of pelleted feed (such as a complete senior feed) or hay pellets by soaking them in a large amount of water for at least an hour until they reach a liquid consistency. After a few days of slurries, Hassel reduces the amount of water gradually until the horse or pony can eat completely dry food—usually within a week or so, depending on the severity of the injury.

Veterinarians at South Eastern Equine Hospital report that when damage occurs to the esophagus wall, this structure tends to contract as it heals and form strictures that narrow the tube. These can predispose the horse to choking again in the future, so make sure you have your veterinarian release an obstruction quickly and promptly.

The recommended diet for the hospital’s 5-year-old Thoroughbred patient post-choke consisted of a gruel or mash. His veterinarians say any complete pelleted feed that can be soaked enough to make a soft mash is appropriate until inflammation subsides, typically within three to five days. Stay clear of abrasive feeds until the esophagus heals ­completely.

Wrapping It Up

Esophageal obstruction can result from ingesting any feed or foreign material. Rapid or aggressive intake is the most common cause. Identify horses at a higher risk for choke, such as older horses with dental problems, and manage them carefully. Techniques to slow consumption rate and reduce aggressive feeding behaviors can help minimize choke risk, including soaking hay or grain, adding to or adjusting feed buckets, and using grazing muzzles.