Feed Senior Horses

By Devan Catalano, Phd / 18 August, 2021

Starting off with a tough question, when is a horse a senior horse? Though this is a commonly asked question, there isn’t a clear-cut definition. Collectively, the equine community typically starts referring to horses as senior when the horse reaches their upper teens (15+), but this will vary from horse to horse. Additionally, as our knowledge of how to care for senior horses increases, their life span has increased. What the equine world considered “senior” 30 years ago could be a horse in her prime today.

Perhaps we need to answer a different question first—what makes a horse a senior horse? Instead of defining senior chronologically, it is better to look at the horse from a physiological approach. Again, while there is no true clear-cut definition, we generally consider a horse to be “senior” when we start noticing changes in their appearance and behavior.

Signs of an aging or “senior” horse:

• Greying hair, typically seen around the nose first (while this doesn’t affect horse health, it is a good indicator to keep an eye out for the following changes)

• Other changes in hair and hoof quality

• Changes in ability to maintain overall weight and condition

• Changes in muscling, often seen first within the topline

• Decreased ability to chew hay and other feed

• Loss of mobility

• Reduced vision or hearing

Factors that impact your horse’s health as they age

These aging characteristics and factors are impacted by breed, genetics, and, most importantly, management of the horse throughout their life. Although research on senior horses is fairly limited, the two proven factors to impact a horse’s health later in life include their dental care history and their deworming history.

Dental Care history

A horse’s teeth continuously erupt, or grow, over time. Horses chew using a side-to-side circular motion that grinds their feed between an upper and lower molar. Any disruption to this motion will create an uneven chewing surface. This is why it is important for horses to receive yearly dental care from an equine dentist or veterinarian trained to float teeth. The dentist will check for any abnormal wear patterns, infections, and other issues that will affect your horse’s ability to chew hay properly. If they find any abnormalities, they will correct it. Like most things in life, it is much easier to resolve a small problem than a large one. By maintaining annual visits, you can prevent major issues down the road.

Here’s a very personal example of why this is so important: almost 20 years ago, I got my first horse—a 20-year-old appendix QH mare. Upon her first dental exam, the dentist noted a very abnormal wear pattern towards the back of her mouth. At some point in her life, part of a lower molar had broken off. Without previous annual visits, the corresponding upper molar had grown unevenly, and they fit together like two puzzle pieces, which is not what you want for a smooth chewing motion. We worked to correct this problem; however, more regular dental care when she was younger could have prevented it.

Deworming history

Even if a horse has good teeth and can chew their feed properly, changes to the digestive tract can create challenges with nutrient absorption. While a study out of Michigan State University showed no differences in nutrient digestion and absorption between middle-aged horses and senior horses, one component of management that affects the GI tract is parasite control. If a horse does not receive proper deworming treatment throughout their life, this will result in changes to the digestive tract surface. The changes to the GI tract may limit your horse’s ability to absorb nutrients effectively, ultimately affecting their overall health.

A word of caution: Before trotting off to deworm your horse, please consider the increasing problem of deworming resistance. Current best management practices recommend doing a fecal egg count (FEC) to determine your horse’s shedding status. Work with your veterinarian to select the right product for your geographic region, your horse’s parasite load, and the current season.

How to feed your senior horse

First step—can your horse properly chew hay? “Quidding” is the most common and obvious sign that a horse cannot chew forage properly. Quids are balls of partially chewed forage that ultimately ends up on the ground.

If your horse can chew hay, you are in good shape! You can continue to feed your horse as you have been. Some changes you can consider are:

• Feed softer hay. Less mature hay will have softer leaves and stems that your aged horse may have an easier time consuming. When I managed a 100-head herd, I
  “cherry picked” the softest flakes from each bale for the senior horses.

• Turn out to pasture when possible. This will encourage more voluntary movement, which keeps the whole system going. While this is helpful for all horses, it is especially helpful for horses that have slowed down due to their age. Fresh pasture grass is going to be easier to chew than hay.

• Despite proper chewing, you may still need to provide more calories to maintain your horse’s weight than when they were ten. If your horse has a strong appetite, simply feed them more. If they reach a limit on what they will eat but still need to gain weight, try mixing in some alfalfa and/or change to a senior feed that is high in fat. This will be a condense way to provide calories, along with packing a nutritional punch.

Is your horse struggling to chew hay?

Don’t fret! First, what are your horse’s limitations? Can they chew soft, fine hay? What about pasture? Many times, we can extend a horse’s ability to eat long stem forage by being very selective about what we feed them. Did your vet or dentist claim that your horse is done with traditional hay? There are still several options.

• Look into chopped forages. This is the equivalent of cutting up your child’s food for them to make it easier for them to eat it. You can purchase prechopped forage or get creative with a lawn mower or other equipment to “pre-chew” hay for your horse.

• Use forage cubes or pellets. These are both hay in processed forms which vary in particle size. If your horse is able to safely consume hay cubes, this is closest form of forage for them to consume. However, pellets are generally easier to work with than forage cubes. You can feed pellets soaked or dry(depending on your individual horse’s teeth) which is what makes them easier for your horse. You can find various types of grass pellets, grass-alfalfa mix pellets, and all alfalfa pellets. Alfalfa pellets will contain more calories compared to most grass options.

• Use a senior horse feed. Most senior feeds are designed to be “complete feeds.” This means that they contain enough roughage to meet your horse’s fiber needs. While your horse can have a diet that is 100% complete feed, most senior formulas tend to be fairly high in calories. This means that they don’t need as many pounds of a senior feed to maintain their weight as they would from hay or hay pellets. What I often recommend to clients is to provide a combination of a senior feed and hay pellets or cubes. For an average sized horse, that may look like ten pounds of senior and ten pounds of hay cubes, split into multiple meals throughout the day.

What about senior horses with Cushing’s disease or PPID?

Equine Cushing’s disease is the informal name for the disorder pituitary pars intermedia dysfunction, or PPID. PPID leads to an overproduction of hormones including adrenocorticotropic hormone (ACTH). Diagnosis of PPID comes from evaluation of ACTH levels. This disorder, often referred to as the “old horse disease,” is the result of a drop in dopamine, which controls a specific part of the pituitary gland. Lowered dopamine results in an enlarged pituitary gland, which consequently results in increased production of ACTH. Increased ACTH causes overproduction of cortisol, the stress hormone.

Horses are diagnosed with PPID more and more. The reasons behind this increase are twofold. First, as owner education and recognition of symptoms increase, so do the diagnoses. Second, more and more horses are reaching true old age, which, unfortunately, comes with consequences.

Classic symptoms of PPID include:

• Long shaggy hair coat that does not shed easily

• Increased water consumption and subsequent increased urination

• Excessive sweating

• Loss of muscling (especially the topline)

• Loss of energy/Lethargy

• Insulin resistance and laminitic episodes

• Abnormal fat deposition or patchy fat spots

Another key symptom is a suppressed immune system. This may manifest as:

• Being more prone to infections

• Dental issues

• Hoof abscesses

• Slow wound healing

Not all horse with PPID display any or all of these classic symptoms. The more we learn about this disorder, the more we hear about other interesting symptoms like changes in hair color or pattern. The key is knowing your horse and keeping up with routine veterinary work.

How do you manage a horse with Cushing’s?

Pergolide is the only FDA-approved treatment for PPID. The brand Prascend is most commonly used. Pergolide is the only known effective treatment for controlling ACTH levels. Other treatments, including herbal remedies like Chasteberry, can manage symptoms, but they do not actively reduce ACTH levels.

Also, horses with PPID are commonly insulin resistant. For these horses, a low NSC diet is necessary. If that horse needs additional calories beyond hay, look for a grain-free, low NSC feed such as Woody’s Senior or Woody’s Complete. If they do not need additional calories, ensure their daily nutrient requirements are met with Woody’s Ration Balancer. Many researchers theorize oxidative stress is associated with neuron breakdown that can lead to PPID developing. Help protect your horse against oxidative stress by adding in Woody’s Recovery Plus.