Due to advances in nutrition, veterinary medicine and management practices of horse owners, horses like ourselves are living longer. This means that horses are not uncommon to still be around and competing into their late 20 and 30's. Even though they have reached these years they need to be managed differently to other horses due to several considerations. Senior horses are defined as those whom are older than 15 years. However you must judge your horse individually to see if they need the special requirements that elderly horses may require.

SOMETHING TO CHEW ON!

It's been stated that the best feed in the world will do a horse no good if he can't digest it. So what's stopping the older horse from extracting nutrients from his diet? Let's start at the mouth, and work back.

Foremost on the list of suspects is the inevitable decline of the older horse's dental health. As a horse ages, he gradually wears down the grinding surfaces of his teeth--and while the teeth continue to grow throughout his life, often the wear and tear teeth receive outstrip the replacement rate. In addition, his incisors (vital to tearing off grass and forage from the ground) become more sloping over the years, and as they verge on the horizontal, they become far less efficient at biting down and tearing fibrous foodstuffs.

Dental "hooks" on the molars, a problem for all domestic horses throughout their lives, can compound the problem (and are especially likely if your horse has not had the benefit of routine dental checkups). Older horses also can suffer from broken or missing teeth, usually as the result of trauma (although long-term infections of teeth also occur and can have the same result). A broken tooth is not only painful, it can interrupt the normal dental surfaces and make it next to impossible for your horse to chew. The loss of a molar or premolar also can reduce the ability of the horse to chew his feed--and if a molar or premolar is lost, the opposing teeth will grow into the space, creating a condition called "wave mouth", which further complicates matters.

If an incisor or incisors are lost, your horse might not be able to graze efficiently--so don't depend on pasture to help maintain his condition. There always is the possibility of dental abscesses, often caused by a particle of food, or a foreign object picked up while grazing, lodged in the gum.

All of these dental problems can lead to a loss of appetite or poorly chewed food that might fall out of your horse's mouth. The food that does get swallowed often is harder to digest because it is in larger-than-normal chunks that the body might not be able to break down. In very old horses, the teeth can become so worn that they are practically nonexistent; without the essential grinding surfaces, such a horse has no way of taking in forage or grain in the normal way.

Needless to say, the older horse's teeth should be checked at least twice a year, and floated (rasped) as necessary. Your veterinarian or dentist should pay special attention to the molars at the very back of the jaw, where hooks and points often get neglected.

DIGESTIVE EFFICIENCY

Metabolism of the older horse is somewhat slower than a young horse's, and has a more modest energy expenditure which should mean that his maintenance requirement for energy is lower than it was in his early years. Unfortunately, there are other factors at work that cancel out this effect. Studies have demonstrated that the geriatric horse (usually defined as 15 years or older) suffers from decreased digestive efficiency--the gastrointestinal tract becomes less able to process and extract the nutrients from his feed, so many essential dietary ingredients fail to be absorbed and instead pass through the body untouched. The ability to digest fiber is decreased, and studies in other monogastric (one-stomached) animals suggest that horses probably experience a decrease in stomach acid and enzymes as well as decreased motility of the intestinal tract.

Research on horses indicates that the absorption of protein (essential for the repair of bones and soft tissues) and phosphorus (involved in the strength and resilience of bone, as well as a number of maintenance functions at the cellular level) is compromised in older horses, and that as a result, the requirement for both these minerals is increased as a horse gets older. (The decreased protein absorption actually is the result of decreased retention of nitrogen.) Calcium absorption does not appear to be affected, but if you increase the amount of phosphorus in the diet, it's a good idea to increase the amount of calcium in order to maintain that all-important calcium: phosphorus ratio of 1:1 or better. Starch digestion is another area that appears not to be affected by age.

NUTRITION RESEARCH

Studies were performed in the 1980's to detect decreased digestive efficiency in older horses might be, in part, an indicator of what happens to a horse which suffers years of chronic parasite infestation. The first research in this area was done in the early 1980s, using mares in their 20s which through much of their early lives did not have the benefit of advanced deworming drugs such as ivermectin. Today's older horses, which most likely have had the benefit of better parasite prevention programs throughout their lives, are less likely to show extensive parasite damage in the intestinal tract. Therefore might be able to derive more benefit from their diets, for more years, than those research mares foaled in the 1960s.

Still, it's fairly clear that the ability to digest fiber is compromised in almost all older horses--and since fiber should make up at least 50% of the overall diet by weight, it's a significant problem. Researchers suspect that the difficulty is two-fold: first, many older horses find it hard to chew forage properly, especially when it is fibrous, long-stem hay instead of succulent, young grass; and second, a less-varied and less-efficient population of microorganisms in the colon might make for a less-thorough job of fiber fermentation and nutrient extraction.

The ability to manufacture or absorb certain vitamins also seems to decrease as horse's age. Researchers suspect that the decrease of gut microflora compromises the ability of the horse to manufacture his own B vitamins (normally produced in abundance) as well as vitamin C (ascorbic acid), which is important for the horse's immune function. A healthy horse manufactures sufficient quantities of his own vitamin C, but many older horses, which suffer from pituitary dysfunction (a common result of the aging process) show low blood levels of C, which might make them vulnerable to viral infections.

Geriatric horses also can suffer from decreased kidney and/or liver function, both of which can have an effect on nutrient utilization. Horses are unique in that they excrete excess dietary calcium in their urine, not in their manure as most other species do-so if kidney function becomes impaired, stones of calcium oxalate can build up in the kidney or bladder. There also is the potential for calcium to build up to dangerous levels in the bloodstream. Horses with kidney failure need to be placed on a low calcium diet (less than 0.45% of the overall ration), and protein and phosphorus also should be reduced (to less than 10%, and less than 0.3%, respectively), contrary to the usual recommendations for older horses.

Horses with liver failure might suffer from jaundice, weight loss, lethargy, loss of appetite, and intolerance for fat and protein in the diet. Severely affected horses also could be irritable and circle aimlessly, or press their heads against objects. In contrast to kidney failure, horses with liver problems need increased sugar in their diets in order to maintain blood glucose levels; their diets should emphasize carbohydrates and de-emphasize protein and fats. Because the liver also is a site of the synthesis of B vitamins (especially niacin) and vitamin C, affected horses should be fed a diet supplemented with elevated levels of vitamins and minerals.

FACTORS TO CONSIDER

Finally, there are a number of psychological factors that can contribute to a senior horse's weight loss or lack or condition. First, older equines are, as a rule, are less aggressive--so if they are fed in a group situation with younger horses, they might be pushed aside and are unable to eat all they should. Second, they tend to suffer more than younger horses from stress factors. Hard work, being floated for long distances, or just being chased around the paddock by a more aggressive paddock mate can take a toll on the aging horse and cause him to lose his appetite (a condition clinically called anorexia). In general, it takes less to make an older horse lose his enthusiasm for his meals; even water that is too cold (causing tooth pain) might be enough.

Extremes of weather can be particularly hard for geriatric horses. Because they thermoregulate poorly in their golden years, they require more food energy in order to maintain their internal temperatures in winter conditions. It is generally recommended that in cold weather, horses on the high side of 15 years be fed about 120% of the National Research Council's recommendations for daily intake.

Some horses need even more than this. Some can go up to about 133% of NRC.

This means that in some instances, you might have to exceed 3.0% of your horse's daily body weight per day in feed to help him maintain his condition in winter. To avoid this supplementation of a concentrate ration will be probably required. Ruging him warmly, and providing a good windbreak or shelter in his paddock also will help. In hot, humid conditions, horses also might lose their appetites, so if necessary, body-clipping and consider giving him a cooling mist with the hose when he is looking particularly uncomfortable. Some studs in warmer climates such as Queensland even rig up irrigation hoses on fence lines that spray cool water on their horses several times a day. A lot of studs supply electrolyte blocks or supplement electrolytes within the feeds they provide to ensure correct levels of electrolytes are supplied to their horse.

Many stress factors can be reduced with some basic management changes, such as putting your older horse in a pasture with others of a similar age, rather than rambunctious youngsters. When you feed him, isolate him in a separate paddock or stable, so that he doesn't have to compete for his meals. Making every effort to keep his appetite good is crucial, because once an older horse gets skinny, it can be a real struggle to put weight back on him.

FOOD FOR THOUGHT

There are three primary considerations when you design a diet for your older horse,-ease of chewing, improved digestibility of nutrients, and increased palatability. As your horse's ability to chew and digest fibrous, stemmy hay declines, it's increasingly important to provide him with good-quality pasture (just because it's green doesn't mean it's of good quality--many pastures are largely indigestible weeds!). You also need to provide more easily chewed and digested forms of fiber. Instead of stemmy, mature, 100% grass hay, opt for a higher-quality, softer, and less mature mixed hay with a fairly high legume content (up to 60% or so) , for example clover hay. Your aging equine will find it much easier to chew.

As a test, grab a handful of the hay and squeeze hard--if the hay hurts your hand, it's likely too tough and fibrous. It may be helpful if you spray the hay with water to soften the hay to make it more appealing to him. For most older horses, it's still a good idea to avoid straight lucerne hay, while soft and very palatable, it has an excessively high protein content (up to 25% or so) and is very low in phosphorus. (If your horse has a liver or kidney dysfunction, it's particularly important to avoid high-protein legume hays; instead, choose a grass hay that is immature and thus still fairly soft).

Other forms of fibre's such as Sugar beet pulp and Soy Hulls are fermentable fibres that yield more energy than common fibres sources such as hay and chaff. Generally they are mixed in prepared feeds specifically designed for senior horses. The ease of digestion and chewing of these fibres is a bonus for older horses.

There might come a day when even high-quality, soft hay is too much of a chore for your older equine. In this case, you might have to do some of the chewing for him, so to speak. Chaff is a good start,-you can chop it yourself, or buy it already chopped in bagged form. The worse the condition of your horse's teeth, the more attention you will need to give to his feeding program. If his teeth are rapidly becoming too decayed, feeds high in fat and moderate moistures can be used. A mash (pre chewed) also can be a good way to keep the condition on your horse as well as supply some water in his diet as well.

What about grain? The decreased efficiency of the digestive tract means that most horses will need the help of a little grain to help maintain their condition in their senior years. Processed feeds such as Micronized rations are more readily digested, so in a sense they are "pre-chewed.". Since Micronized feed are individually cooked they maintain their mineral integrity, thus enabling the elderly horse to utilize the minerals available to him.

Feeds with added fat also are an excellent choice for older horses, except for those with liver dysfunction. Fat, in the form of vegetable oils or rice bran, is extremely digestible and can help immeasurably in the task of keeping an older horse's ribs covered, since it contains almost 2 1/2 times more energy, weight for weight, than carbohydrates (grains). Adding fat is an excellent way to increase the energy density of your horse's diet without increasing its volume by more than a few grams.

You can top-dress vegetable oil to a level of up to two cups per day (spread over several meals a day), or choose to buy a feed that is formulated with extra fats (look for a feed tag that lists a crude fat level of at least 5%, and preferably up to 8%).

Most quality feed companies are formulating rations specifically for the senior equine. These are formulated with energy, protein, vitamin and mineral levels all taken into consideration. They tend to be softer to enable consumption by horses with poor teeth. Some even have digestive aids such as Yea Sacc 1026. A live yeast culture, which aids in the digestion of nutrients. These rations added with chaff or soft hay are the safest way to feed you elderly equine. Why?, because the ration has been scientifically balanced for your horse to obtain all the essential nutrients required to keep him in prime condition.

Finally a few check points in formulating your older horse ration:

• Maintain and regularly check teeth
• Feed soft leafy roughages (pasture, hay chaff)
• Do not exceed 1% calcium levels
• Keep balance of Ca:P ratio
• Look for feed designed especially for senior horses eg (HYGAIN EQUINE SENIOR)
• If feeding a formulated feed, choose one that is processed for increased digestion such as Micronizing which contains correct mineral levels
• Take advantages of Live Yeast Cultures

Be willing to experiment to find out what your older horse likes, and what he finds easy to eat. A finicky appetite comes with the territory. And of course, make sure your horse always has access to unlimited amounts of fresh water, since no dehydrated horse maintains a good appetite. In the winter add an extra rug to keep him warmer, which will reduce his energy requirements. Cater to his dwindling interest in food by offering small meals, more often. With a little extra TLC on the nutritional front, most senior horses can continue to lead healthy and productive lives for many years to come.

For more information on feeding the senior horse please contact Hy Gain Feeds on 1300 HYGAIN (494246) or email us.