Health Matters

High on Health

Written by Dr. Justin High on .

We at Quarter Horse News are very happy to announe that Dr. Justin High, D.V.M., will be writing a column for us that will appear in the first print issue of each month, and he will also be blogging on horse health right here at You don't want to miss what this veteran veterinarian has to say!

High is a veterinarian and partner in Reata Equine Hospital in Weatherford, Texas. He graduated vet school from Texas A&M University and completed an internship at The Littleton Equine Medical Center in Denver, Colo. High’s years of practice focuses on the Western performances horse. Send any comments or questions to So help me in welcoming Justin aboard. Here is High on Health!


I don’t know about where you live while you’re reading this, but in Weatherford, Texas, the temperatures have gone from the upper 20’s to the low 70’s and back again several days over the last couple of weeks. As much as I like mild winters, the fluctuations in temperatures are catching up with the horses. Changes from warm to cold can cause many different health issues with your horse. The things we see most are colic and respiratory disease, with the latter being a much more common problem due to all the new 2-year-olds being brought together and started under saddle. The increased concentrations of new horses that may or may not have been vaccinated, mixed with older horses that have been back and forth to the big winter shows, and the normal amount of respiratory bugs that are out there are enough to spike the snot meter in anyone’s barn, but add the 30 most stressful days of a 2-year-old's life on top of that, and there you go.

By far, the most common respiratory bugs that affect horses, especially young ones, this time of year are viral in nature. Flu and rhino viruses are the two bugs that are responsible for the bulk of the sick and snotty horses I see this time of year. I say sick and snotty because the two do not always go together. Meaning some horses have nasal discharge, fever, coughing, etc. and some just have the “snots” with no other symptoms. Granted, some horses do develop the dreaded “S” word this time of year – Strangles – but the viral horses are far more common. Initial symptoms can be similar with fevers over 102.5 degrees, coughing, and slight nasal discharge, and unless physically impossible to do should be isolated from other horses. But, symptoms usually differ between flu/rhino cases and strangles rather quickly. Viral horses will typically have an explosive, non-productive cough with no major lymph node swelling, whereas strangles horses have thicker drainage, wet coughs, and increasingly larger lymph nodes under their throat and jaw line.

For all intents and purposes, horses with fever, coughing and nasal discharge should be handled the same until it is possible, by a veterinary exam, to differentiate the cause(s) of respiratory disease. I prefer to see how the horses are stalled, how many are affected and how long they’ve had trouble before I wade through the physical exams. Taking the time to go through each horse’s physical exam carefully and combining it with a routine CBC (complete blood count) and fibrinogen are the basics in how I sort out sick horses. And sorting out sick horses is much easier said than done. Rarely do I think I get a single source of infection.This time of year, many of the cases I see start as a primary viral upper respiratory infection and can easily wind up with a secondary bacterial, lower respiratory component. Once I have the groundwork done, I will medicate a horse based off what he looks like to get him headed in the right direction as soon as possible. This usually includes medications for fever, immune system stimulants like Zylexis® or Equimmune®, and systemic antibiotics if needed.

Afterward, based on the horse’s temperament, owner’s ability, and medical necessity we will come up with a plan to treat and follow up on the case. But, no amount of medicine can replace the value that comes from administering the right vaccine at the right time. There are several very good vaccines available for flu and rhino virus that are much cheaper than the first round of medications to treat a sick horse. Giving these vaccinations two to three weeks prior to going off to the trainer or show is a minimum to protecting yourself and your horse.



Degenerative Joint Disease

Written by Katie Tims on .

The repetitive, powerful movements expected of horses when holding a cow or sliding to a stop often cause inflammation that can eventually lead to degenerative joint disease or osteoarthritis.

Joints in horses are grouped under three headings: fibrous, cartilaginous and synovial. The fibrous and cartilaginous joints have limited or no movement and are not particularly prone to injury. The third type, the synovial joints, are the ones most affected by trauma. They’re the ones that keep vets busy with the needle.

Synovial joints come in both high- and low-motion versions. The hock, for example, has four separate joints with the lower two having relatively little motion while the two higher joints have a broad range of movement. Synovial joints are characterized by two bones that fit nicely together and are covered on the ends by a soft cushion of articular cartilage. The portion of the cartilage covering the weight-bearing parts of the bone is referred to as the minisus. Synovial fluid floats between the bones, allowing lubricating compounds to keep the cartilage smooth and supple. The synovial membrane holds the fluid in place while the fibrous joint capsule connects the bones and provides stability to the joint. Muscles, ligaments and tendons attach to the bones and maintain strength and structure.

For a horse to move optimally, all parts of the joint must be in perfect working order. The articular cartilage is what allows the leg bones to bend comfortably and uniformly. Unfortunately, the rigorous demands on today’s performance horses often lead to injuries that result in the destructive course of osteoarthritis.

In its simplest form, osteoarthritis is the depletion of the articular cartilage, which includes the meniscus and the cartilage that extends past the weight-bearing parts of the bone. The disease is caused by trauma, excessive use and at least one form of corticosteroids. It can result from just one injury or osteoarthritis might take years to develop. There are no tried-and-true rules for identifying precisely when and why a horse begins to lose cartilage.

There are three classifications of injuries that lead to osteoarthritis: Type 1 includes injury to the supporting ligaments (sprains) and inflammation of the joint capsule (capsulitis) or synovial membrane (synovitis); Type 2 includes severe sprains, intra-articular fractures and meniscal tears; Type 3 is the result of repeated or un-healed injuries that left lingering damage.


Written by Hannah Wellman on .

Choke is the word commonly used when a horse has an obstruction of the esophagus. The esophagus is the structure that takes the food from the mouth to the stomach. It has no absorptive properties. Choke is the most common esophageal problem. It can be caused either by something the horse has swallowed getting stuck, or from a mass or constriction of the esophagus itself.

Clinical signs of Choke are more commonly seen soon after eating but may occur at anytime. Horses may show signs related to difficulty swallowing, retching, excess salivation, or evidence of food particles or saliva coming from the nostrils. The esophagus runs down the left side of the neck. In some cases, if the obstruction is in the first half of the esophagus, a bulge may be visible on the lower neck associated with the blockage.

Choke is a veterinary emergency. Do not offer the horse any more food once signs develop. Once the veterinarian arrives they may try to pass a tube to relieve the blockage. If there is too much resistance, due to risk of perforation, other diagnostics may need to be used to evaluate the cause such as endoscopy (a camera that can be passed into the esophagus), X-rays or ultrasound.

The biggest risk factors associated with this problem include esophageal perforation and secondary aspiration pneumonia due to the inhalation of food when retching or coughing. For these reasons, even if it looks like the horse was able to resolve the blockage on itʼs own, a veterinarian should still be consulted.


Written by Hannah Wellman on .

Salmonella is a type of bacteria that can cause disease in the horse. Gastrointestinal disease is the most common presentation, especially in the adult horse. There are over 2,500 different subtypes of Salmonella classified, though there are several main groups that are routinely present in horses.

When a horse is suffering from disease related to Salmonella, we call it Salmonellosis. The most common clinical sign is diarrhea. Salmonella is also thought to play a role in some impactions and generalized enteritis conditions. Horses with Salmonellosis often display colic signs. This often precedes the onset of diarrhea. Horses may develop endotoxemia in severe cases.

We diagnose Salmonellosis based on fecal culture and/or advanced laboratory tests called ELISA and PCR. Not all horses that culture positive have clinical signs of disease, which has suggested there may be a carrier state. Also, horses that are highly suspicious of the disease do not always culture positive.

Treatment of Salmonellosis is based largely on supportive care as the disease appears self-limiting. Fluid therapy is very important. Anti-inflammatories and antidiarrhial agents are often used, too. The use of antibiotics is determined on a case-by-case basis.

Salmonellosis is contagious so any horse suspected of having the disease should be isolated and a veterinarian should be called immediately. Strict hygiene should be in place to avoid contamination of the environment.

Many hospitals have biosecurity protocols in place to constantly monitor for Salmonella. The environment (diagnostic areas, stalls etc) are monitored and all hospitalized horses are constantly tested for the disease. This, combined with glove and boot protocols and isolation of all suspected cases, assists in the prevention of disease spread.


Written by Hannah Wellman on .

Endotoxemia is produced when a certain class of bacteria multiply or die. They are called gram-negative bacteria. These bacteria are present in the normal horse. There is a large population gram-negative bacteria in the intestinal tract. The mucosal surface of the healthy equine intestine acts as a protective barrier against this toxin. However, if this barrier is disrupted, the toxin can leak into the bloodstream of the horse causing systemic disease. Processes that can damage the mucosal barrier include infection, inflammation, trauma or reduced circulation to the area.

Not all endotoxin comes from the gut. Horses with gram-negative infections in other areas like the uterus or lungs may also become endotoxemic. Horses may initially show signs related to the underlying cause of the endotoxemia. If the gut is involved they may colic. They may be dull and depressed. They usually have a significant change in their gum color, often a bright pink or purplish color and you may see a line running just above their teeth (“toxic line”). Horses may sweat, have a high heart rate, have cold extremities and develop edema. Horses that suffer from endotoxemia are at a higher risk for developing laminitis.

Endotoxemia is a veterinary emergency. Blood work is often done to determine the severity of the disease process. These cases generally require hospitalization and aggressive management. Once stabilized the veterinarian will search for the underlying cause. Supportive therapy is key, along with treatment of the initiating cause and preventative measures to reduce side effects like laminitis and organ damage. Endotoxemia can be fatal, even with advanced veterinary care.


Written by Hannah Wellman on .

Strangles is caused by a bacteria called Streptococcus equi (S. equi). It is a highly contagious disease seen throughout the United States and internationally. Many people associate the disease with swelling under the chin area, which is caused by infection of the surrounding lymph nodes. Horses affected commonly also show a marked fever and develop a nasal discharge which may start clear and become yellowish. They may also develop a cough, become inappetent and are often dull and depressed.

The bacteria which causes Strangles enters a horse through the mucosa in the mouth or nose. It is taken by the body to local lymph nodes where it proliferates causing inflammation and infection. These lymph nodes become swollen and painful, and often rupture, draining through the skin or into the gutteral pouches. In severe cases these lymph nodes may become so swollen that they decrease the horseʼs ability to breathe. Diagnosis is often made based on history and clinical signs. Definitive diagnosis is made by collection and culture of a discharge sample or nasal swab by your veterinarian. It is important to confirm that the horse has Strangles as it determines management and quarantine strategies.

Treatment is centered around supportive care. The most important feature is aggressive strategies to limit the spread to other horses in the area. It is important to be honest with your veterinarian about horse movement and management so that they can assist you to contain the disease while treating those that have developed clinical signs.

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