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Feeding the Senior Horse

May 2018 by Tania Cubbitt, PhD, & Stephen Duren, PhD, HyGain Feeds, www.hygain.com.au

The nutritional management of the senior horse is challenging as there is no set criteria that defines ‘old age’ or the ‘senior’ horse. The nutrient requirements of senior horses differ from other classes of horses because of the changes in metabolic and digestive efficiency that accompany the aging process. It is not uncommon to hear of individual horses in their upper 20’s or early 30’s. Why are horses living so long? 

Several potential reasons exist, including improved internal parasite control, better nutrition, advances in veterinary care and less strenuous work. As horses become old, their bodies naturally begin to fail, which leaves their owners with the responsibility of providing proper care.

When does a horse become nutritionally senior? 

In general, horses between 18 and 20 years of age are thought to be approaching their senior years. 

However, a better description of senior is when a horse becomes a ‘Nutritional Senior’ or ‘Nutritionally Senior’. 

A nutritionally senior horse is one that can no longer eat their normal diet and maintain proper body condition. 

Nutritionally senior horses typically have one or more of the following conditions: decreased nutrient absorption, persistent dental problems or increased sensitivity to stress. 

A geriatric horse is a condition related to diseases and disorders caused by aging, not by a specific number of years spent on Earth. Understanding these conditions will allow care givers to modify feeding programs to ensure proper nutrition.

Physical signs in the aged horse

  • Loss of weight,
  • Decrease in body condition,
  • Loss of muscle tone and mass over the topline,
  • Sway backed appearance,
  • Chronic diarrhoea and dehydration, reduced mobility and agility,
  • Greying of muzzle and coat,
  • Decrease in coat and hoof quality,
  • Reduced fat deposits above the eyes, 
  • Dental problems.

Digestive and metabolic changes in the senior horse

Decreased Nutrient Absorption: Exposure of horses to intestinal parasites causes scarring of the digestive tract. These scars result in damage to the lining of the intestine, which decreases nutrient absorption. Improvements in de-worming products have delayed and minimised damage from internal parasites, but over a lifetime this damage still occurs. 

To further compound digestion problems, the horse’s digestive tract begins to lose efficiency with advancing age. 

Research studies have shown ‘Nutritionally Senior’ horses require additional protein, phosphorus and certain vitamins. Proper protein intake is particularly important in senior horses. 

Senior horses with inadequate protein intake will break down muscle tissue to provide essential protein for other body functions. Muscle wasting is common in aged horses that are not getting the proper amounts of protein in the diet. In creating feeds for senior horses, the protein content of the diet is similar to that which would be fed to a yearling, rather than that of a mature horse.

Dental Problems: As horses age, their teeth wear down from chewing and grinding their feed. As a tooth wears, additional tooth erupts from the jawbone in a constant cycle. The process continues until the roots holding the teeth in place become short and the tooth is lost. 

Old horses often loose teeth and have difficulty chewing their feed. Horses begin the digestive process in the mouth by reducing the physical size of feed to a suitable size for proper digestion. 

Without proper chewing of feed, the horse will not effectively digest its feed. Old horses will often drop or spill grain from their mouths, or they wad up hay or grass into partially chewed balls and drop them on the ground. Inefficient chewing of feed can lead to digestive upset, weight loss and nutrient deficiency. 

While the loss of teeth cannot be prevented, proper care of the teeth can delay problems. Horses with dental issues must rely on alternate sources of pasture and hay as their ability to chew is limited. 

Forage products, including chaff and fibre nuggets, such as HYGAIN® FIBRESSENTIAL®, can be used as substitute forage sources. Complete feeds, such as HYGAIN ZERO®, that use high fibre by-products, such as lupin and soybean hulls, can be used as a quality forage source. These forage sources are often fed wet or in a ‘mash’ form to minimise issues of choke associated with the inability to properly chew.  

Stress: Old horses are very sensitive to stress, which can come in the form of changes in temperature, changes in housing, dealing with the pecking order imposed by other horses or pain. 

Old horses are particularly sensitive to changes in temperature, predominantly cold temperatures. 

Sensitivity to cold may result from decreased fat cover that acts as insulation to the cold. Sensitivity to cold could also be a result of the senior horse’s inability to chew and take in adequate amounts of fibre. It is the fermentation of fibre in the horse’s hindgut that produces heat to help warm the horse. 

Senior horses are also sensitive to changes in their surroundings. Changing paddocks, stalls or routine tend to cause weight loss in senior horses. Adding horses to, or taking horses out of, a pasture containing an old horse changes the herd dynamics and may send the old horse to the bottom of the pecking order. This can also lead to weight loss since the old horse may not be given adequate access to feed. 

Finally, old horses may have old injuries or arthritis that causes them to be in constant pain. Horses that experience pain will suffer from loss of appetite and drop in body condition. To alleviate the weight loss associated with stress, senior horses should be provided adequate shelter, waterproof blankets and be kept with a consistent group of horses in familiar surroundings. 

Senior horses should also be fed a high quality, senior horse feed to facilitate maintenance of body weight. 

Overweight: Not all older horses are hard keepers. Some will hold their weight easily and may actually become too heavy since they are not exercised as often or as intensely as their younger counterparts. These horses may begin to accumulate fat at a rate that may be detrimental to their health. 

Horses that become too heavy may stress their bones and joints, and aggravate any existing lameness conditions, such as arthritis and navicular syndrome. Therefore, it is important to ensure the horse is meeting all of their nutritional requirements without gaining an excessive amount of weight. 

Allowing ample turnout time for horses that are not in a routine riding program will provide them with some exercise, and allow them to maintain muscle tone and a healthy body condition.

Disease: Senior and geriatric horses are subject to many age related diseases. 

Chronic infections, liver or kidney failure, anaemia, Cushings Disease and respiratory problems are but a few disease conditions that affect old horses. 

Each of these diseases requires veterinary treatment and nutritional support. The nutrition support provided depends on the specific disease, but proper nutrition is a key to recovery and strengthening of the immune system. Further, proper nutrition will go a long way to helping prevent many of the health conditions that plague old horses. 

Osteoarthritis is the most common cause of joint discomfort in old horses. Osteoarthritis is a progressive and permanent degeneration of the articular surfaces of the joint caused by inflammation. Healthy articular cartilage provides a smooth, slippery surface that allows free movement and contributes to the shock-absorbing properties of the joint. As osteoarthritis sets in, articular cartilage becomes compromised, due to inflammation caused by wear and tear, disrupting the normally smooth surface and resulting in stiffness and discomfort. 

Hyaluronic acid is an integral component of both synovial fluid and cartilage in healthy joints. Glucosamine is the building block of cartilage formation, and helps to rehabilitate cartilage and reduce the progression of osteoarthritis. 

HYGAIN®’s joint supplement, FLEXION®, contains the highly absorbable Glucosamine HCL along with Methylsulfonylmethane (MSM), Vitamin C and critical minerals, aiding the nourishment of joints, cartilage and connective tissue.

A senior horse’s diet requirements

When it has been determined a horse is indeed ‘nutritionally senior’, each horse must be evaluated and fed as an individual. The main goal when feeding a senior horse should be to maintain an optimal body condition, with the shoulders and neck blending smoothly into the body, the ribs not visually distinguishable, but easily felt and a flat back (no crease or ridge).

The most important component in the diet for senior horses is forage (hay/pasture). Many old horses maintain good body condition on pasture, but lose condition when forced to rely on hay. 

Weight loss associated with being fed hay is likely the result of the inability of the old horse to properly chew. Replacing the baled hay with hay that has been ground, and compressed into a pellet or nugget will aid digestion. 

Soaking these pellets or nuggets will further soften the product and enhance consumption. Senior horses also require additional energy, protein, vitamins and minerals to maintain good health. 

Energy requirements: Generally, senior horses in good body condition are less active than their younger counterparts and only have maintenance energy requirements. However, if the horse has difficulty maintaining body weight then a higher caloric diet is needed. 

Energy dense calorie sources, such as HYGAIN® RBO® Equine Performance Oil® and HYGAIN TRU GAIN®, an extruded high fat supplement are ideal for weight gain. Full feeds, such as HYGAIN® SENIOR® or HYGAIN TRU CARE®, are advisable as they provide conditioning energy from quality sources, such as highly digestible fibre, micronised barley and HYGAIN RBO®. 

Protein requirements: Older horses in good body condition have protein requirements that are similar to those of horses at maintenance. Horses that are underweight or have lost muscle mass require higher quality proteins and increased quantity. Both HYGAIN® SENIOR® AND HYGAIN TRU CARE® provide high quality protein sources in adequate amounts.

Mineral requirements: Limited research has been conducted on senior horse vitamin and mineral requirements, but older horses would potentially benefit from supplementation of vitamins E, B, and C to help boost the immune and digestive function. Yea Sacc®1026 is a live yeast culture that increases the digestibility of the fibre, phosphorus and calcium, and is included in HYGAIN TRU CARE® and HYGAIN® EQUINE SENIOR® for its benefits. 

Summary

The main point to remember when developing feeding programs for senior horses is these animals should be treated as individual cases and the diet optimised for their specific needs. With proper care and optimal nutrition, we can improve the quality of life of our senior horses, and also extend their lives even further.