The 'Not Quite Right' Horse

Steps you and your veterinarian can take to get to the bottom of subtle problems

Wonderful thing about spending time with your horse is that you become familiar with his disposition and attitude through your many interactions, from grooming to feeding to riding. You know how he heads for his favorite spot to roll when you turn him out, how he starts watching the house exactly 25 minutes before dinner, and how he quietly snorts as you lead him in on cool mornings. So, when you peer over the paddock gate in the morning and get a gut feeling that something isn’t quite right, it’s probably a good thing to trust your instincts.

Does your horse appear quieter than normal? Instead of his usual enthusiastic greeting at the gate or stall door, is he withdrawn? Is he typically social but standing by himself in a corner of the field? Or, is he an avid eater who’s left some of his meal behind? These are just a few possible scenarios of not-quite-right horse behavior, says Sarah Reuss, VMD, Dipl. ACVIM, equine technical manager at Boehringer Ingelheim Animal Health, who is based in Duluth, Georgia. Other signs can be musculoskeletal. For instance, when you turned him out after yesterday’s ride, he strode with purpose toward the hay rack but now stands with little weight on one leg, not willing to move.

“Signs such as nasal discharge, being off feed, or reluctance to move may be easily detected,” says Tiffany Hall, DVM, Dipl. ACVIM, ACVECC, of the Equine Medical Center of Ocala, Florida. “However, more subtle signs include changes in behavior, low head carriage and ear position, a dull look to the eyes, and a general lack of interaction.”

Reuss adds that if you carefully assess a horse’s face, you might notice tightening of the muzzle or tension in the eyelids, which are signs on the horse grimace scale used for pain scoring. (See “Is Your Horse Hurting?”)

These are all telltale signs that something isn’t right. Your horse might not vocalize his feelings as a human would, but his body posture and behavior speak volumes. Where do you start to determine what might be wrong?

The 'Not Quite Right' Horse

First Steps

Collecting your horse’s vital signs is a good place to begin. Doing so can provide revealing information, especially if you know your horse’s normal parameters. So, before a problem arises, practice taking basic vital signs (TheHorse.com/VitalSignsTool): temperature, pulse, respiratory rate, mucous membrane color, capillary refill time. Be familiar with how much manure your horse usually ­produces and its consistency, and his water consumption. Then, when he seems a little “off,” you can collect this information and compare it to his normal.

“After gathering vital signs, observe for coughing, nasal discharge, swollen lymph nodes under the jaw and in the throatlatch area, and look for limb and/or abdominal swelling,” adds Reuss. “This information helps your vet know how quickly your horse needs to be seen and informs him or her of any special diagnostic equipment or biosecurity precautions that need to be taken.”

Hall strongly advises against trying to wait it out to see if your horse will improve. “Delays in evaluation could result in higher expense to treat and poorer prognosis for recovery, such as with prolonged colic or pneumonia,” she says.

Reuss recommends doing a little detective work first, then contacting your veterinarian immediately to discuss your findings and help determine the urgency of your horse’s condition.

“A horse that isn’t eating or is passing abnormal (or no) manure can progress very quickly into full-blown colic or colitis (diarrhea-causing inflammation of the colon), either of which can become life-threatening,” she says.

For example, some causes of diarrhea, such as Potomac horse fever (PHF), often start with a low-grade fever and very mild clinical signs. Immediate identification and implementation of appropriate therapy make it easier to thwart the illness, says Reuss. If you don’t recognize the problem and instead allow it to progress for several days, she adds, the horse is at greater risk of the painful hoof disease laminitis or even death. Having a simple conversation with your veterinarian can help you avoid serious consequences.

Information to Share With Your Vet

“Rectal temperature is probably the most important thing to note,” says Reuss. This is especially important if you plan to give a non-steroidal anti-­inflammatory drug (NSAID) such as phenylbutazone (Bute) or flunixin meglumine (Banamine) prior to your veterinarian’s assessment, she adds. Knowing if fever is present helps narrow the list of potential disease causes and also helps inform whether other horses might be at risk.

When your veterinarian arrives, he or she will collect a patient history. “A thorough vaccine history—which vaccines, when given, and who administered—also helps to rule out specific illnesses,” says Reuss. “Advise your vet about travel history, not just of your horse but any other horses on the farm. This informs about the risk for different infectious diseases.”

“Your veterinarian may also ask if new horses have entered the property or if you’ve recently changed feed type or source or if there have been changes to your horse’s daily routine and exercise,” adds Hall. “Make sure to list any medications and all supplements you’ve given to your horse.”

Your veterinarian then conducts a comprehensive physical exam while continuing to gather history. “By asking the right questions and listening for clues in the history, it may be possible to narrow the list of potential causes fairly quickly,” says Reuss.

Hall emphasizes the value of historical information about vital signs or concurrent conditions, such as pituitary pars intermedia dysfunction (PPID, formerly known as equine Cushing’s disease) and equine metabolic syndrome (EMS), gastric ulcer syndrome, or osteoarthritis, to name a few. A comprehensive physical examination often helps the veterinarian localize the issue to a body system: Is it gastrointestinal, respiratory, or neurologic, for example?

“As part of a thorough examination, your vet will observe your horse’s behavior and stance because some ­conditions, such as laminitis, have very classic presentations,” says Hall. “A stethoscope is used to evaluate for cardiac abnormalities, such as an arrhythmia or murmur, or abnormal respiratory noise in the lungs, including wheezes, crackles, or tracheal mucus. In addition, listening to the abdomen with a stethoscope assesses for changes to gastrointestinal sounds that indicate gas colic, lack of intestinal activity, or the presence of sand.

“A thorough examination also includes palpation of limbs and digital pulses, as well as assessment of hydration of the gums and looking at the eyes,” she continues. The veterinarian feels for a digital pulse on either the inner or outer side of the fetlock, and he or she can get a good idea of the horse’s overall hydration status by checking the gums for saliva. Additionally, “in some cases a rectal exam (transrectal palpation) of the abdomen is an important diagnostic procedure.”

Based on this compilation of clinical findings, your veterinarian will make recommendations for further evaluation with additional diagnostics, some of which he or she can do right there at the farm and others that might require a trip to the clinic.

Diagnostic Testing Options

You veterinarian has a variety of tests to choose from, depending on his or her observations so far. “Baseline bloodwork includes a complete blood count (CBC) and chemistry panel,” says Hall. “The CBC tells how the immune system is responding and provides insight as to the presence of an infectious condition. It measures numbers of red blood cells, white blood cells, and platelets to help differentiate if the horse is experiencing an infectious and/or inflammatory disease. Biochemistry evaluates the status of various organ system functions to help guide therapy.”

Serum amyloid A (SAA) and fibrinogen blood testing also yield information about inflammation and possible infection. All this information from bloodwork doesn’t necessarily localize the process to an organ system or specific area of the body, but it does provide important information, says Reuss. 

Hall concurs. “Recommended diagnostics are selected not only to help determine a diagnosis, but also to rule out many conditions,” she says. “It can be frustrating at times for test results to be within a ‘normal’ range, but even normal results help a veterinarian’s diagnostic evaluation of your horse.”

Reviewing all these bloodwork results might help your veterinarian determine if he or she needs to perform diagnostics to further narrow the possibilities or has enough rationale to start a specific ­treatment.

Hall explains that some veterinarians are board-certified and specialize in specific areas of veterinary medicine, “just as MDs who go through residency and board-certification,” she notes. Sometimes, it is valuable to obtain input from such specialists.

She and Reuss both are diplomates in the American College of Veterinary Internal Medicine (ACVIM), for instance, and Hall is also a diplomate in the American College of Veterinary Emergency and Critical Care (ACVECC).

Imaging can be very helpful once you and your veterinarian have identified a source of the problem.

“For example,” Reuss says, “a suspect problem with the respiratory tract makes use of thoracic ultrasound and/or endoscopy of the airway to confirm a diagnosis. For a problem with the gastrointestinal tract, ultrasound of the abdomen and/or endoscopic exam of the stomach (gastroscopy) helps with diagnosis. Gastroscopy is frequently performed in horses that aren’t quite right and maybe have some performance limitations, often due to gastric ulcer syndrome.”

Both endoscopy and gastroscopy involve passing a thin tube and camera through the horse’s nostrils to see the airways or stomach.

Beyond basic bloodwork and imaging, “specific samples are relevant to test if a horse has an evident infection,” says Reuss. “For example, fever and diarrhea inform the importance of testing manure and blood for Salmonella, Potomac horse fever (in which case you’re looking for Neorickettsia risticii), equine coronavirus (different from what’s causing the human coronavirus pandemic). For a horse with respiratory signs of infection, blood is collected and a nasal swab obtained to test for viruses such as influenza or herpes and for bacterial infection caused by strangles (Streptococcus equi).

“Bacterial culture and antibiotic sensitivity testing are appropriate to perform on mucopurulent (containing mucus and pus) nasal discharge or an aspirated sample from swollen lymph nodes,” she continues. “Respiratory signs associated with no fever but the horse shows exercise intolerance may be more indicative of asthma. Then, a bronchoalveolar lavage technique samples cells from the lower respiratory tract to confirm or rule out this possibility based on results of cytology (microscopic examination of sampled cells).”

Your veterinarian might also consider certain diagnoses based on where you live. Tick-borne Lyme disease, for instance, is of concern in certain geographical areas such as the Northeast.

“Unfortunately, there is limited accuracy of blood testing for Lyme—many horses have been exposed (to the causative bacterium) and may have elevated antibody titers but don’t necessarily have active disease; this makes it an overly diagnosed syndrome,” says Reuss. “The same also holds true for equine protozoal myeloencephalitis (EPM, for which the causative protozoa are found throughout the United States). Diagnostic testing for these two diseases is done only in horses demonstrating specific clinical signs and once other diseases have been ruled out.”

Take-Home Message

Remember: Your horse is unable to speak for himself, and your veterinarian often acts as a detective in determining what might be causing him to seem not quite right.

“Your veterinarian wants to team with you to provide the best possible care and return your horse to full health—­sometimes this necessitates repeat visits and follow-up to rule out common things first,” says Hall. “Sometimes it means treating symptoms without a specific diagnosis, and sometimes there is a need to refer to a specialist to get to the bottom of the problem. Besides working together to promote your horse’s health through preventive care, what is most important is that communication between owner and veterinarian remains open when illness does occur.”