The Senior Horse

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senior horse older horse aging horse laminitis older horse impaction colic older horse cushings older horse ppid older horse dental problems older horse

Common Conditions, Challenges and Pain Recognition

By Equine Guelph

Keeping a horse comfortable into their senior years requires an attentive caretaker backed by a knowledgeable team. It is important to seek the input from your veterinarian and farrier to help maintain the health of an elderly equine and to spot conditions that will need special treatment sooner rather than later. Recognizing changes and not just dismissing them as “old age setting in” is a large part of the responsibility assumed when caring for the senior horse.

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The senior horse will enjoy the company of pasture mates, but stress from herd dynamics can play a role in weight loss. Older horses may need to be fed separately so they don’t have to compete with dominant pasture mates for food and water.

Pain Recognition

As a prey species, horses are predisposed to hide pain so as not to attract the attention of predators. Horses can be very stoic and not show the signs of pain until it becomes severe. Often the first signs of pain are changes in behaviour or attitude, as in the following examples: 

  • A horse that normally greets you at the stall door is now hiding at the back of the stall
  • Rigid posture 
  • Guarding part of their body or reluctance to be handled 
  • Head lowering, squinting eyes, limp ears 
  • Teeth-grinding 
  • Increased flight behaviour 
  • Aggression 
  • More subdued than usual 
  • Decrease in responsiveness 
  • Flaring of nostrils 
  • Looking back at the flank 
  • Restlessness 
  • Stoic or pained expression, dull eyes 
  • Awkward tail carriage or aggressively swishing tail 
  • Decreased performance 
  • Reluctance to perform tasks which have already been mastered 
  • Reluctance to move  
  • Reluctance to drink cold water (indicates oral/dental pain)

Recognizing pain is not always as obvious as the horse thrashing or rolling violently on the ground, or the horse that is limping. The suddenly quiet, withdrawn horse may be suffering from the pain of a stomach ulcer or another non-visible ailment. It is important to resolve sources of pain early on. Chronic pain can cause depression and stress. It can also have a negative impact on appetite, the immune system and tissue healing, and can increase the risk for developing gastric ulceration and colitis (inflammation of the colon).

Be on the lookout every time you groom for lumps, bumps, cuts, heat, or swelling, and pay particular attention if your horse displays sensitivity to touch. Also take note of any decrease in bowel movements as an early warning sign for colic. Knowing the baseline vitals for your horse is important to help you assess health. 

Colic 

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Older horses tend to have a reduced drive to drink, putting them at higher risk of impaction colic. A reluctance to drink cold water may indicate dental pain. Photo: iStock/Eileen Groome

Colic risk does increase in senior horses. Gut motility issues are more common in older horses, which can lead to an increased risk of impaction colic. Other issues in the senior gastro-intestinal tract that elevate the risk of colic include tumours and increased parasite load. Older horses tend to have a reduced drive to drink, and inadequate intake of water is also a risk factor. Difficulty in chewing feed can result in undigested food entering the gut, which can also lead to gas or impaction colic.

Digestion is impaired if a horse is unable to grind food properly. Schedule regular dental checkups with your veterinarian to make sure teeth are aligned with no jagged edges and your senior horse has a balanced surface to effectively grind food. If changes in feed are required due to difficulty in chewing, be sure to make these changes slowly to allow gut bacteria and enzymes to adapt.

Dental Health 

Extra diligence needs to be paid to dental health in the senior horse. The front teeth continually erupt at an angle that increases as they age. Cases of unbalanced chewing surfaces escalate as the horse ages. Horses wear down their teeth as they chew but that wear is not always even. The development of sharp points in the mouth is much more prevalent in the elderly equine and this can result in ulcerations, reluctance to chew food, poor digestion, and a higher incidence of choke. Severely uneven wear can lead to a condition called “wave mouth” where at least two molars are higher than the others, so that when viewed from the side, the grinding surfaces produce a wave-like pattern. Missing or loose teeth can lead to “step mouth” where one tooth grows longer than the others, usually because the corresponding tooth in the opposite jaw is missing or broken and could not wear down its opposite. Step mouth requires regular inspection and care as food can get packed in, leading to dental disease, abscess, or infection.

In very elderly horses, the teeth may lose their rough edges and become entirely smooth, which results in an inability to grind food. Horses with smooth mouth should be fed highly digestible feeds that are easy to eat, such as soaked hay cubes or beet pulp – your veterinarian or equine nutritionist will be able to recommend the best course of management.

Annual dental exams are recommended for all horses and should be performed twice a year for elderly horses. Foul odours coming from the mouth, nasal discharge, loose incisors, broken teeth, red or inflamed gums, quidding (chewing then dropping balled-up lumps of food), weight loss, not finishing feed, and resistance to the bridle are all reasons to call the vet and have the teeth checked. If you notice your horse is no longer chewing in a regular circular pattern, this can be an indicator of sharp points and uneven wear, which also warrants a vet appointment for dental care.

Maintaining good dental health into old age is probably one of the single best ways to encourage longevity. It is far more difficult to address and fix a chronic dental issue once the horse has reached later age.

Weight Loss 

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For the senior horse that is losing weight, several factors should be investigated including parasite load, infection, dental care, and diet. Photo: Stukenbrock/Wikimedia Commons

The senior horse that is dropping pounds requires a closer look. Rule out factors that can cause weight loss, such as parasite burden, tumours and infections. Dental care may need to be addressed if the horse is not grinding its food properly. If the enamel is soft, or teeth are missing or worn, changes from coarse feeds to softer food may be needed. Easy-to-digest supplements may include vegetable oil. Discuss with your veterinarian or equine nutritionist the best methods to satisfy your senior’s dietary needs. Stay on the lookout for quidding as this indicates a dental problem.

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This older Trakehner stallion would benefit from an increase in feed and a blanket to help him stay warm and maintain body condition over the winter. Photo: Canstock/DragoNika

Winters can begin to take a tougher toll on the senior horse. The energy required for a horse to thermoregulate in the cold is often underestimated. The senior may require an increase in feed and a blanket to help stay warm. Checking body condition score should be part of every senior horse’s weekly routine. Old age is no excuse for an overly thin equine – body condition score should be between four and seven. Discuss with your veterinarian or equine nutritionist the best methods to satisfy your senior’s dietary needs and make any dietary changes slowly.

Arthritis 

The older horse commonly has an accumulation of wear and tear plus past injuries. Sixty percent of all equine lameness is due to arthritis, and the common causes are: 

  • Physical injury – which triggers inflammation.
  • Everyday wear and tear – repetitive and excessive force on a joint may wear down the supporting tissues of the joints.
  • Concussive forces – weight-bearing joints, such as the knee, hock, fetlock, pastern, and coffin joints, are more prone to be arthritic since they endure the majority of the concussive forces. Maintaining correct hoof balance is important as a poorly balanced hoof can further overload joints.
  • Poor conformation – which may cause abnormal forces, placing additional strain on joints.
  • Other injuries – a joint fracture or a bacterial infection (septic arthritis) will stimulate an inflammatory response that damages the joint surfaces.

Not all horses exhibit lameness at the onset of arthritis.  Early diagnosis is the key in managing the progression of arthritis and joint disease. Owners should not delay in calling the vet if heat, swelling, pain, or loss of function is detected. 

Laminitis 

Laminitis has many different causes and is not limited to the horse or pony that eats an overabundance of rich grass (often when given unrestricted access to rich spring pastures). It can develop from eating poisonous plants, overconsumption of grain, retaining the placenta after foaling, a disease that spikes a prolonged high temperature, the metabolic changes associated with equine metabolic syndrome (EMS), or trauma from repeated concussive forces (road founder).

Laminitis can occur in any breed, at any age; however, overweight horses and those with metabolic syndromes (more frequent in older horses) do have a higher risk of laminitis.  Laminitis is also a common sign of pituitary pars intermedia dysfunction (PPID) in the older horse. The best defence against laminitis is to prevent the aforementioned causes from occurring. 

Horses suffering laminitis will usually be reluctant to move and often stand with their front feet well out in front of them, rocking back on their heels seeking relief from the pain. They can appear as if they are walking on eggshells. The hoof will be hot to touch. In severe cases, the laminae weakens to the point where the coffin bone may rotate and/or sink.

Stall rest, cold therapy, corrective shoeing, pain management, and anti-inflammatory therapy are some of the many treatments your veterinarian may use to try and treat laminitis. The severity of the laminitis and the length of time it persists will be factors in determining how soon, or if, the horse will be able to return to its previous level of activity.

The first step in preventing recurring laminitis is to find the cause. Managing laminitis requires a plan with both veterinarian and farrier working together with regular assessments. 

Pituitary Pars Intermedia Dysfunction (PPID) or Cushing’s Disease

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A long, curly hair coat that does not shed normally is the classic symptom of PPID or Cushing’s disease. Photo: Abujoy/Wikimedia Commons

Horses and ponies with PPID suffer an increase in cortisol levels. Excess cortisol is produced by the adrenal gland because the part of the brain that controls the adrenal gland (the pituitary gland) is not functioning properly. High cortisol levels increase blood sugar (glucose) levels and suppress the immune system. This hormonal disease often goes unnoticed as signs are slow to develop and are often mistaken as normal in the aging process. The disease typically occurs in older equids, but has been diagnosed in horses and ponies as young as ten.   While all ages, genders, and breeds are susceptible to developing PPID, ponies and some breeds of horses (specifically Latin-blooded horses such as Paso Finos, Peruvian Pasos, Spanish Mustangs, Arabs, and Morgans) seem to develop PPID more frequently.

Horses and ponies with PPID will often develop a pot-belly appearance. You may notice other changes in body conformation.  Common signs of PPID include formation of fat pads on top of the neck, tail head, and above and around the eyes. Horses with PPID also tend to lose muscle.

Look for abnormal hair coat including patches of long hair on the legs, wavy hair on the neck, changes in coat colour or shedding patterns, and unusual whisker growth.

Up to 70 percent of horses seen for laminitis have been found to have PPID. It is often treated without identifying the underlying cause.

More early warning signs for PPID include decreased athletic performance, change in attitude/lethargy, and delayed shedding of hair coat.

In more advanced stages of PPID the signs can include lethargy, depression, generalized hypertrichosis (long shaggy hair coat), loss of seasonal coat shedding, skeletal muscle loss, rounded abdomen, abnormal sweating (increased or decreased), excessive thirst, excessive passage of urine, chronic or recurrent infections (i.e., sole abscess, ulcers, etc.), laminitis, absent reproductive cycle/infertility, and hyperglycemia (high glucose levels in the blood).

Early diagnosis is important. Contact your veterinarian if you notice any of the above signs in your older horse. After a complete examination, if your veterinarian suspects PPID, he or she may recommend following up with some blood tests to check for the disease. The most common tests to diagnose equine PPID include measuring resting (basal) ACTH (adrenocorticotrophic hormone) and fasting insulin level. Studies have indicated success managing the clinical signs of PPID with the drug pergolide mesylate. It acts on the pituitary to ultimately decrease circulating ACTH and other hormone levels. Daily treatment is needed to improve the horse’s quality of life by reducing disease signs and the risk of other illnesses. Your veterinarian will be able to advise if pergolide mesylate is a treatment option for your horse.

As of yet there is no cure for PPID but there are ways to help control the signs and improve the health of the horse by working closely with your veterinarian. Horses with PPID also require extra diligence by providing regular hoof and dental care, and body clipping. Making sure changes in diet occur slowly and effectively, and treating any infections will help promote health in the horse with PPID. Dietary restrictions, which should be discussed with your veterinarian, may include decreased starch/carbohydrate feed, low protein forage (no alfalfa), limited fresh grass especially in the spring, and restricted sugar intake (no molasses feeds or treats).

Early diagnosis provides the best opportunity to manage PPID and minimize the progression of symptoms that can be career and life limiting.

Equine Metabolic Syndrome (EMS) 

There is a fair bit of confusion in the horse world over mixing up PPID and EMS as they share many of the same clinical signs.  Horses with PPID may also have some of the features of EMS, but horses with EMS only rarely have PPID.

Equine Metabolic Syndrome had many previous names – peripheral Cushing’s syndrome, pseudo-Cushing’s syndrome, hypothyroidism, and insulin resistance syndrome.

Both PPID and EMS require working with your veterinarian, planning regular checkups for blood work, dental care, regular hoof care, and special attention to dietary needs. Performing diagnostics is necessary to conclude which disorder you are dealing with and determine the best treatment options.   Horses with EMS do not display hypertrichosis (excessive hair growth) or delayed shedding. EMS tends to be seen in horses over five years of age, where PPID cases are more common in horses over 15. It is possible for horses with EMS to develop PPID. Working with a veterinarian for accurate diagnosis is critical in determining future management. Laminitis and obesity are often the first clues in identifying both disorders.   

Reprinted with the kind permission of Equine Guelph.

Main Photo: Photo: Shutterstock/Wolf Avni

This article was originally published in the September/October 2016 issue of Canadian Horse Journal.

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