Special Considerations for the Aged Horse
Dr. Andrew Hoffman and Dr. Philip Johnson
When a horse is in pain most or all the time
Arthritis and Navicular Disease
Pain and function (mobility) are the big issues that determine quality of life. Although certain joints sustain the greatest wear and tear throughout the life of a horse, it is not always these "obvious" sore joints that act up later in life.
Horses with arthritis are generally stiff, especially in the morning after they have lain motionless for a period of time. The problem gets even worse in cold or wet weather. The stiffness worsens over time, and eventually the horse is so painful that he doesn't want to move, and may even groan. Arthritis in the legs is more obvious, in that the horse's mobility has declined, and there is a progressive "crouching" stance or actual limping. However, neck arthritis can also be a big problem, although more subtle. In this case, the horse exhibits difficulty reaching the ground. Pain and loss of function (immobility) add up in the arthritic horse.
There are many options for treating arthritis. For the horse with single joint problems that can be pinpointed, local treatments are available. However, most old horses have multiple joints with arthritis all at once, often in inaccessible regions such as the hip, or neck.
The best option is the judicious use of pain killers or anti-inflammatories. Examples include phenylbutazone, Banamine® (flunixin meglumine) and ketoprofen. Eventually it becomes difficult to get enough of these painkillers into the horse without causing side effects, including loss of appetite, gastric ulcers, weight loss and diarrhea. You should talk to your veterinarian about a schedule of treatments to soften that possibility. Cartilage protective agents should also be considered at this point, for example chondroitin sulfate and polysulfated glucosaminoglycans (PSGAGs), which are available as supplements or injections.
This causes obvious signs of heel pain, and is easily managed early in life with corrective shoeing and oral medications, or in some cases, by surgery ("neurectomy"). The choice to perform neurectomy (to "nerve") an old horse depends on what other problems exist, and must not be done without serious consideration of potential complications.
Orthopedic (arthritis, navicular) problems are untreatable:
When he is completely reliant on pain medications
When he doesn't respond to medications
When he has frequent side effects of the medications (e.g. ulcers, colic) that are unmanageable
When he is reluctant to move, get up, stretch or move about
When he doesn't interact with you or other horses
When he shows aggression
When he shies away from contact
When he starts dropping weight
Economics obviously plays a role here as well, since anti-inflammatory and cartilage protective agents, if used, can be expensive. Determining when arthritis is a consideration for euthanasia is most difficult, because the problems are long-standing, so get another opinion and step back.
Heart Valve Disease
Heart murmurs are a dime a dozen in old horses, but they are mostly benign. However, with the procession of years, the heart valves start to "wear out." The valves most commonly affected include the aortic and mitral valves, because they are under the most stress. They function to control blood flow through and out of the left ventricle, the part of the heart that pumps blood to every place in the body except the lungs.
When these valves become leaky, you can see back flow of blood within the heart on ultrasound, which ultimately causes the heart to fail due to inadequate delivery of blood, and therefore oxygen, to tissues. This is one reason that it is common to detect heart murmurs in old horses, although many are inconsequential and do not require further attention.
An ultrasound examination ("echocardiogram") provides information that will forewarn you if the murmur is serious. If a loud murmur should arise, it should be checked then rechecked at no more than 6 month intervals. If it gets louder or there are signs of poor heart function (poor pulses, lethargy, dark mucous membranes, increasing breathing rate), it should be treated. If the heart is rechecked by ultrasound, the cardiologist can see how fast the problem is progressing, and help you prepare for a downturn in quality of life if that seems imminent.
Symptoms of heart failure include: a horse with a loud murmur that is lethargic, dropping weight, reluctant to move, stocking up, accumulating edema on the belly, disinterested in food, exhibiting frequent restlessness. Also, poor pulses, visible pulses in the neck, bluish or dark mucous membranes, increased breathing effort, or froth from the nostrils are present. These symptoms need to be addressed right away, and may be treatable for a period of time, usually no more than a few days to weeks.
Kidney failure is a problem that most horses face if they live long enough, and it is a major cause of unexplained weight loss. The disease can be recognized by the following symptoms:
Progressive weight loss over weeks to months
Edema formation (legs, belly, under jaw or face)
Pale mucous membranes
Tarter accumulation on the teeth
Increased drinking and soaking the stall with urine.
A urinalysis, ultrasound of the kidney and perhaps a biopsy should be pursued to evaluate the extent of the problem. As you can see, there are many causes of weight loss in the older horse, so a thorough evaluation is necessary in every case.
"Broken wind, COPD" is extremely common in the older horse. Up to 20 percent of horses get heaves, and it can be highly debilitating and even cause sudden death. Fortunately, there are great options for the horse today, including hypo-allergenic hay, pelleted feeds to replace hay (since these horses are ultra-sensitive to mold found in hay), and oral and inhaled medications. If the environment can be managed diligently, and the horse put on medications without side effects, horses rarely die from heaves today. They may, on the other hand, not be used for riding.
One company, Trudell Medical International (London, Ontario) makes an inhaler for horses that allows delivery of steroids or bronchodilators directly to the lung, allowing for control of the disease for years, without side effects. The steroid keeps the airway inflammation (the basis for heaves) in check, and prevents attacks. The bronchodilator markedly reduces the work of breathing. Clenbuterol is an oral bronchodilator that reduces the symptoms of heaves in a high a percentage of cases.
Without any treatment, the breathing problems in these horses worsen, and they can die from either this problem or heart failure. Make certain they are not exposed to hay; if you are diligent, it's possible for them to live a long happy life without attacks of heaves. In some cases, however, even the most diligent environmental management does not prevent heaves, because there are so many things in the environment that cause it.
Horses with heaves that do not respond to medications and being taken off hay, have constant difficult breathing (increased abdominal effort, nasal flaring), are weak, or have progressive weight loss, are candidates for euthanasia.
Of note, unlike people, horses do not appear to be affected by hardening of the arteries, heart attack (MI), stroke, senile dementia or Alzheimer's disease.