by: Marcia King

Click this link for the original article in its entirety: TheHorse.com

Whether you consider a horse to be old at 18 or 25, at some point, senior horses are going to start showing clinical signs of aging–moving more slowly or stiffly, becoming unthrifty, developing a dull coat, or displaying subtle or obvious signs of a disease process. Here are some of the common problems you could encounter in your aged friend and what you should know about those topics to help him through those golden years.

In today’s Part 3 we will cover the following topics:

– Eye Problems

– Hoof Changes

– Reproductive Function

– Respiratory Factors

– Weight Loss

– Take-Home Message

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Eye Problems

“Any older animal will eventually develop age-related ocular disease,” says Ursula M. Dietrich, DrMedVet, Dipl. ACVO, ECVO, assistant professor in the department of small animal medicine and surgery at the College of Veterinary Medicine, University of Georgia. “This is due to the biologic clock ticking and decline of the cells’ regeneration capacity, but it is not known if the aging process may also be influenced by environment, nutrition, care, etc. Treatment of some ocular diseases in horses can be costly and difficult, and they may take many weeks to heal.”

In horses, the most commonly seen eye disorders are nucleus sclerosis, corneal problems, and vitreous/retina changes. Cataracts, on the other hand, may be age-related, but are most commonly seen with chronic uveitis (moon blindness) in the horse.

Nucleus sclerosis occurs when lens fibers, which grow throughout life, become more densely packed within the center of the lens. “This gives the lens a less clear appearance and a little bit of a bluish sheen,” says Dietrich. “However, the animal is still able to see. There is no therapy indicated.”

“Cataract unrelated to other ocular disease is less frequently observed in horses than it is dogs,” explains Dietrich. “However, secondary cataract due to chronic inflammation (e.g., equine recurrent uveitis) is more commonly diagnosed. The longer the inflammation persists in the eye, the more likely is the development of a cataract.”

Cataract surgery can be done if the cataracts are primary (unrelated to other ocular disease)–usually in very young horses. If the cataracts are secondary to inflammation, surgery is not advised, as inflammation can worsen with the surgery.

Corneal edema occurs when cell layers that protect the cornea on the inside and outside become less efficient. This allows fluid to get into the cornea, Dietrich says, causing corneal edema (fluid accumulation). Chronic inflammation inside the eye can also cause corneal edema. Clinical signs are usually a bluish-whitish haze in the cornea that can affect part or all of the cornea.

“If the edema becomes chronic, corneal ulcers could occur,” Dietrich warns. Edema due to age-related degeneration cannot be resolved, but prophylactic treatment is warranted to help prevent an ulcer formation.

Corneal ulcers in horses are caused by age-related changes, trauma, or other conditions. Those ulcers can become secondarily infected with bacteria or fungus. “Corneal ulceration is usually a very painful disease,” says Dietrich. “The horse is squinting, tearing, and the conjunctiva is usually very red.” Prognosis is best in superficial ulcers that are treated quickly. However, age-related ulcers might take a long time to heal and can recur. Deeper or unresolved ulcers can result in perforation of the cornea and loss of the eye.

Treat ulcers with topical antibiotics and anti-fungals to prevent secondary infection. “If the ulcer is deep, surgery such as a conjunctival flap may be necessary to give mechanical support and promote healing,” says Dietrich.

Vitreous/retina changes occur with aging. As the horse gets older, vitreous (the gel that fills the eyeball between the lens and the retina) liquefies and horses start to have “floaters” or loose fibers in the eye. “It is difficult to objectively say how much this affects horse vision,” Dietrich says. “Very severe vitreous degeneration will certainly affect vision; in some cases horses are spooking or refusing to jump.”

Hoof Changes

Aging horses often experience slowed hoof growth, a more boxy hoof shape, or flares, says Henry Heymering, Certified Journeyman Farrier, Registered Master Farrier, and president of the Guild of Professional Farriers. “Sidebones, ringbone, and arthritis tend to make the hoof boxy. Various aches and pains can cause flares–for example, hip and/or pelvis pain will cause flares to the insides of the front feet (particularly common in older broodmares), while shoulder tightness or soreness can cause flares to the outsides of front feet. Treating these hoof conditions isn’t necessarily a problem–most everything can be managed with care.”

Due to degenerative joint disease or other lameness problems, older equines can have trouble tolerating farrier exams and hoof work. “Joints don’t bend so well,” Heymering states. “Horses can’t flex as far or stand as long with one foot up. The farrier may have to shoe the horse without putting the hoof between his legs, and by working on each hoof a little at a time instead of completing each hoof in turn.”

For these situations, Cruz suggests administering anti-inflammatories and analgesics a few days prior to farrier work.

Reproductive Function

The most common reproductive problems seen in older mares involve intrauterine cysts and problems with uterine defense/clearance mechanisms. Older stallions frequently experience reduced semen motility.

Intrauterine cysts occur inside the horns of the uterus, explains Hope. “Smaller cysts can look like pregnancies at early stages, while bigger cysts interfere with the mare becoming pregnant simply by occupying space.” There are no clinical signs; cysts are detected via ultrasound.

Treatment consists of puncturing the cysts or removing them with a laser. Although affected mares usually form more cysts within a few years, removal does extend the period of fertility. “Remove the cysts a couple of months prior to breeding to give the uterus a chance to recover,” Hope advises.

Inefficient uterine defense mechanisms and poor uterine clearance hinder mare fertility. When either mechanism fails, debris, bacteria, and fluid accumulate in the uterus, hindering pregnancy. Uterine discharge suggests a problem, with ultrasound and culture confirming the diagnosis.

To treat, the veterinarian flushes the uterus to rid the mare of as much bacteria as possible and uses appropriate antibiotics. “Some bacteria don’t present a lot of problems, but some bacteria can be very stubborn, somewhat resistant to some antibiotics, and more difficult to clear up,” Hope says. It can take a month to restore the uterine environment, so treatment should be done at least one month prior to breeding.

Reduced motility of sperm can be age-related. “Oftentimes, aged stallions do not have a good concentration of semen,” Hope says. There is no treatment, although reducing the number of breedings per day helps preserve better concentration.

Arthritis can take its toll on any stallion. The physical strength required to mount a mare on a regular basis is great, and stallions with large books that have to mount mares several times a day will eventually begin to show wear and tear. Joint injections and anti-inflammatories can help make stallions more comfortable, as can mounting a dummy or learning to be collected from the ground.

Respiratory Factors

Recurrent airway obstruction (RAO) or heaves (chronic obstructive pulmonary disease) is a common pulmonary problem in middle-aged to older horses. The cause of RAO is believed to be due to a hypersensitivity reaction to hay and dust, says Beard. “Clinical signs of RAO (during an episode) include a chronic cough, dilated nostrils, increased effort to expire (breathe out), and in some cases a nasal discharge.”

Management consists of reducing exposure to mold or dust by keeping horses outside, wetting down hay, and/or eliminating hay completely (switch to complete pelleted feeds). “In moderate to severe episodes, glucocorticoids and bronchodilators may be beneficial,” Beard says. “Use only when necessary, as glucocorticoids can result in immunosuppression, laminitis, and adrenal suppression, while bronchodilator drugs lose effectiveness if used for more than a few days.”

Prognosis depends on the ability of the owner to change the environment, and the severity of the disease.

Weight Loss

Weight loss in older horses occurs for several reasons, including underlying disease, bad dentition, and impaired ability to absorb nutrients; it’s imperative to identify the cause of weight loss in order to initiate proper treatment. Treatment and prognosis depend on underlying cause. A good, well-balanced diet can help, Hope states. (See page 95 for more information on feeding older horses.)

Take-Home Message

It’s an unhappy fact of life that sooner or later disease, injury, or euthanasia will claim your horse’s life. But by scheduling regular wellness exams with your veterinarian, practicing good management, monitoring physical and behavioral changes, and initiating prompt veterinary attention when changes occur, you can optimize the quality and quantity of your aged equine’s life.