Longevity…according to TheHorse.com

In barns across America horse owners are talking about their senior horses. They’re posting photos of them on social media platforms and asking questions about their care in online forums. Meanwhile, veterinarians are noticing an increase in senior patients in their practices, and researchers are discovering an upward trend in senior horse population numbers.

With all the old horses out there, it’s important to recognize the financial obligation involved with owning one, because, as horses age, health care needs and their cost can increase depending on what conditions arise. Armed with an understanding of the array of health problems that can crop up and how to monitor for and manage them, owners can mitigate the costs and enjoy their senior horses well into their golden years.

In this article we’ll review senior horse research studies and hear from veterinarians about what conditions these horses face and how husbandry requirements change across their life span.

There is little to add or comment upon here; the scene is simply being set. However, the second paragraph does rankle a bit given the assumption that health problems will arise and need managing; the preference surely would be to avoid provoking these problems in the first place

First things first: What is a senior horse? Mary Rose Paradis, DVM, MS, Dipl. ACVIM, associate professor emerita at Tufts University’s Cummings School of Veterinary Medicine, in North Grafton, Massachusetts, says researchers around the world disagree on the age a horse is considered old.

Various researchers in England and Australia have completed studies with senior horses starting at age 15, while others have used horses age 20 and older.

Paradis has been studying younger horses and comparing their health data to that of older horses, looking for trends in disease progression. In one of her studies she surveyed U.S. owners, asking them when they thought their horses were starting to show signs of aging—the average response was 23. Researchers in England and Australia reported seeing early degenerative changes most frequently around 18 to 19 in some, but not all, study horses.

As a guideline, Paradis suggests considering your horse aging around 18 to 20 years and having your veterinarian get health baselines for future reference.

First things first: indeed, what is a senior horse? As Paradis explains, there is no consensus among researchers with some, but clearly not all, English and Australian studies considering 15 the starting point.

Paradis is said to have been comparing younger and older horse health data but no mention is made of what even she considers –or has studied– as ‘younger’ or ‘older’.

Interesting to note that her survey of owners brought up an average age of 23 while English and Australian research showed frequent degeneration at 18 to 19…but what is missing here is a reference to the management schemes in place. Horse management, that covers everything from weaning, age broken in and work regime to stabling, feeding practices and farriery. All these factors can have an important influence upon the ageing of a horse–and also its life-expectancy.

Paradis herself suggests between 18 and 20… which is like telling a 35 year-old human that he’s past it !

Paradis looked at age demographics in a 2003 study she completed with Margaret Brosnahan, DVM, PhD, Dipl. ACVIM, a clinical assistant professor at Midwestern University, in Glendale, Arizona. They found that the percentage of horses older than 20 in the university’s annual caseload increased from 2.2% in 1989 to 12.5% in 1999—an almost sixfold increase over a decade.

While Paradis studies horses within a hospital setting, the National Animal Health Monitoring System (NAHMS) surveys horse owners, industry stakeholders, and government officials periodically to gain an overview of the horse industry based on responses from farm owners with more than five horses. Paradis says NAHMS results likely underestimate older horse numbers because many retired horses live on smaller farms.

In its 1998 study the NAHMS program unit found that 7.5% of U.S. horses were 20 or older, while in 2015 it found that 11.4% of U.S. horses were 20 or older. Of that 11.4%, 1.5% were 30 or older. This could lead to today’s supposition that horses are living longer.   

It is indeed quite possible, even probable, that horses are living longer. Nevertheless, the figures reported are not clearly analysed. When changing attitudes to horses are taken into consideration, added to the advances in equine medical care and treatment, there is a logic behind this greater life-expectancy

Injured horses are less rapidly sent to the abattoir but rather undergo clinical and or medical treatment. Frequently to their detriment, it must be said, since the aim often is to get the horse ridden again as quickly as possible rather than to effect a proper and complete recovery.

Many common health issues are treatable these days, and, with more and more people indeed treating these issues, the price of treatment is somewhat reduced relatively when compared with a few years ago. Also, fewer people accept simply dumping a horse that is no longer (deemed) capable of working; an increasing number of riding-centre animals and even racehorses is being adopted upon their retirement. In the affluent 90s and 2000s particularly, people were more able to afford to do this; however, we are currently seeing a trend where the reverse is happening with numerous owners experiencing economical uncertainty and an increasing number of horses being put down. Will this show a new trend downwards in the life-expectancy of the horse?

When we think about the top senior horse health problems, we need to consider whether a condition is truly one of only older horses or whether it’s a disease that has worsened over time and appears more prominently in old age.

“I think the biggest health issue is the fact that we hardly ever see one thing in isolation,” says Ann Dwyer, DVM, a private equine practitioner at Genesee Valley Equine Clinic, in Scottsville, New York. “When you are older, every single system in your body has undergone the changes that the years bring.”

Paradis says older horses are usually seen for veterinary care because of the gastrointestinal, musculoskeletal, and respiratory systems.

The comments are essentially clear and well argued. We do indeed need to consider whether the horse has seen a recent onset of a disease or whether it is a slow degeneration more marked with age; life itself wears the body. Nevertheless, the last sentence can be seen as somewhat superfluous (or could be better explained). A major part of veterinary care for horses of any age is related to musculoskeletal problems, often due to questionable management and/or riding practices. For the other disorders, there is a clear logic in these reasons [for seeking veterinary care]: the horses are (considered) older and thus work less or not at all. They may be less likely to have the acute traumas associated with the active worked horse but they have probably suffered from mismanagement for a much greater length of time and are now paying for it.

Paradis says the disease most commonly associated with old age in the horse is pituitary pars intermedia dysfunction (PPID), commonly known as equine Cushing’s disease. While horses as young as 5-7 can have PPID, she says a large percentage of senior horses develop it, as risk increases with age. This incurable but treatable disorder of the pituitary gland’s pars intermedia is characterized by excessive hair coat, delayed shedding, muscle wasting, abnormal fat distribution, laminitis, recurrent infections, and more.

PPID (equine Cushing’s disease) is indeed a disease associated primarily with the older horse. What is not discussed is why PPID is notable in the senior horse and why the risk –supposedly– increases with age. There is only talk of treatment (there is no cure) but none of prevention.

Dwyer sees many musculoskeletal conditions in older horses, usually from a combination of arthritis and soft tissue diseases such as tendonitis or desmitis (tendon or ligament inflammation, respectively).

Musculoskeletal problems were the second-most-common problem reported in the Brosnahan study. Of the horses seen by university veterinarians for lameness, 37.5% had the hoof disease laminitis (mostly secondary to PPID, she says), while 55% had lameness classified as degenerative disease.

Paradis says some older horses might experience progressive degeneration of the suspensory ligaments (which attach at the top/back of the cannon bone, split two-thirds of the way down the cannon, and attached to the sesamoids) in the hind limbs or be predisposed to osteochondral disease caused by stiff and brittle cartilage.

While it is true that little can be done for a genetic predisposition towards certain diseases, such as brittle cartilage and possibly desmitis, there is much that can be done to prevent the (early) onset of many conditions. Arthritis and tendinitis [sic], for example, although not entirely avoidable, are very frequently a combined result of working practices and farriery.

“Colic is always a big fear for the (owner of the) older horse,” says Paradis, who says 44% of small intestine problems found in her senior horse research were due to lipomas.

Dwyer sees many of these strangulating fatty tumors, which wrap around the small intestine and cut off circulation or cause an obstruction. She calls pedunculated lipomas (benign fatty masses originating from the mesentery, a membrane that supplies blood to the intestines and connects them to the body walls) one of the two most common life-threatening or -ending emergencies she sees in older horses. The other is severe arthritis in the spine or other skeletal region, which can prevent a horse from rising.

Colic is a big fear for ANY horse owner…any horse of any age can have gastrointestinal problems (colic is a non-medical umbrella term for any problem of the digestive system). Like musculoskeletal issues, it is not always avoidable but is often related to management and working practices.

In 2012 British researchers found that 95% of horses over 15 years of age have dental abnormalities; however, owners surveyed in that study reported that only 10% of the horses had dental disease.

These conditions include a smooth mouth (where the teeth are worn down to root level), wave mouth (unven wearing of the cheek teeth), step mouth (where one tooth is missing and the opposing tooth is overgrown), hooks (sharp points), shear mouth (malocclusion—when the jaws and teeth don’t align—producing marked enamel pointing), and equine odontoclastic tooth resorption and hypercementosis (EOTRH).

Dwyer says she’s concerned about the rise of EOTRH, which is a painful disease of the incisor and canine teeth. It often requires surgical extraction of multiple teeth to restore a horse’s comfort.

Paradis says dental disease probably plays a large role in the incidence of large colon impaction and esophageal choke in older horses. Dental issues often prevent horses from chewing and digesting feed properly, which can lead to these and other conditions, along with weight loss.

Again little surprise here. Although the actual demographics are not mentioned, despite their likely having a profound effect on the overall results, it can be reasonably postulated that the majority of horses surveyed is going to be those kept under traditional conditions and following traditional regimes. Once again, there is no mention of causes and, even more disturbingly, no mention of prevention.

Two ocular conditions that are part of the eye’s normal aging process are cataracts and senile retinopathy (age-related retina damage), says Fernando Malalana, DVM, Dipl. ECEIM, FHEA, MRCVS, RCVS, European specialist in equine internal medicine at the University of Liverpool Equine Hospital, in England. However, other eye conditions relate to a lifetime of accumulated damage from ongoing inflammation inside the eye, he says. Some can be halted if owners pick up on signs early and seek proper treatment. Other conditions, such as recurrent uveitis or glaucoma, might progress to the point horses need long-term medication and/or surgery.

Dwyer estimates that 1-2% of her practice population loses vision in one or both eyes at some point. “By the time you get to an old horse population, you’re going to see a lot of blind or partially blind older horses,” she says. “But now a lot more people are maintaining blind horses, and many of those horses still have productive lives.”

No particular comment here. There is always going to be a chance of ocular degeneration with age and this is generally unavoidable. However, it would have been worth noting in the article that Appaloosa horses carry a genetic deviation which can often lead to the (early) onset of equine recurring uveitis (ERU) –sometimes known as  recurrent iridocyclitis or moon blindness.

Paradis says it’s important for veterinarians to auscultate (listen with a stethoscope) the heart because older horses can develop heart murmurs if the aortic valve becomes leaky with age.

Dwyer also says it’s extremely common to find heart murmurs in aged horses but, in her experience, it’s rare for them to be of clinical concern. However, if she observes clinical signs such as a cough, unusual swelling, or exercise intolerance in these horses, she refers them to an equine cardiologist for a workup.

Leaky valves, whether in humans, horses, cats or cars, are a sign of advancing years. As the article states, there is little issue here but in occasional cases it can be of greater concern. Nevertheless, an overworked heart is also more likely to show earlier signs of problems. And this is something that can be prevented or at least slowed down.

When Paradis studied respiratory issues among horses of all ages, she found no difference in their pulmonary function or in lung fluid cytology (microscopic examination of sampled cells), meaning respiratory issues in older horses are not a result of aging lungs.

“If your older horse is having breathing problems, it’s probably due to disease, not just because he is old,” she says. “If you have an older horse with a cough or increased respiratory rate, it’s probably because they have inflammatory airway disease (IAD, a mild condition usually seen in younger equine athletes), and you can treat that. Whereas if it was an aging change, as the lungs started to get worse, there would be nothing you could do.”

Dwyer adds that heaves (now known as equine asthma, a more severe, chronic condition than IAD) might become worse in affected horses as they age.

While the ageing of lungs does not present a problem, it is clear that there are diseases which can. And as with many diseases, they are often preventable –or at least, avoidable– by simple management expedients. But again, no mention…

Dwyer says cancer is rarer in horses than in dogs or people. However, she says melanomas that began in middle age (around 14-15 years old) might multiply or expand, causing obstructions that create serious issues such as hindered defecation. In addition, she sees squamous cell carcinomas of the penis in older males. 

‘Rarer…than in dogs or people’ but no mention of the clinically known fact that grey horses are more likely to develop melanomas than other colours.

There may be environmental factors at play here but unlike most other diseases, there is little we can do to prevent the onset of cancer. No further comment.

The recommendation by Dwyer is somewhat laughable. For a start, ‘designing diets to maintain proper weight’ is a nonsense. It is principally because of ‘designed diets’ that horses have so many problems.

Paradis’ contention that ‘you need to think about the training’ if you are going to compete with a senior is also a proved nonsense. As explained by Patrick Galloux in an IFCE web conference in February 2019, the horse –even if it has done little or nothing in 5 months– is capable of giving almost full capacity very rapidly, even at 25 years of age. If it cannot, then we should be examining its management…

The ‘weekend warrior’ comment sums it all up, actually. This is the life of many horses, of all ages.

An interesting point regarding medication is that Brosnahan reported 6% of young horses on medication…that is actually a lot. Maybe we should be asking why so many young horses; it could also explain part of the 25% of older horses. But again, just when do we consider we are medicating an ‘older’ horse, and what are we treating?

There may –possibly– be some advantage in giving joint supplements such as MSM but their efficacy is not always clear. However, the main question here is why 66% feel the need to supplement vitamins and minerals? And were they doing this before they considered their horse to be older? Many people feed supplements because they are duped into believing they are necessary –often by other owners who in their turn have been duped…– without any proper understanding.

Agreed, manual therapies can help. They can help the younger horse too, especially given the general living and working conditions often encountered.

With correct management, expenses should little change as the horse ages. Senior feeds do indeed cost more – but, as with all commercial feeds, are completely unnecessary. If your farrier costs decrease, they will most likely be compensated for by the medication needed to treat the disorders resulting from having been shod. And oral care will only increase noticeably if the horse has not seen a dentist while being mismanaged most of its younger life.

Dwyer sums up her senior horse care advice with the main thing she says owners need to think about: “If you are going to keep your horse into old age, be aware that old age can go well into the 30s,” she says. “No one can predict which issues that particular horse is going to have, but every geriatric horse is going to have some issues. Whatever those issues are, they will bring some expense over and above the normal husbandry costs.”

‘…old age can go well into the 30s’. In a healthy horse it should go well into the 30s. ‘No one can predict which issues that particular horse is going to have…’; no they can’t, but they can do their best to avoid these issues occurring in the first place.