If you look in a field of older horses, chances are you'll see some skinny ones, some fat ones, and some that look just right. Every horse ages differently and, thus, their nutritional needs vary.
At the 2012 Kentucky Equine Research (KER) Conference, held May 17-18 in Lexington, Ky., Kathleen Crandell, an equine nutritionist at KER in Versailles, Ky., discussed potential nutritional challenges aged horses face and some options for feeding the different demographics of senior horses.
Challenges for Aged Horses
Aging, Crandell said, is a "highly individual" process, but "horses that are well cared for during their youth and middle ages have a better chance of obtaining a high quality of life as they age." Thus, not all horses will develop challenges, disease, or nutritional deficits at the same time. One study, she said, evaluated the digestive capacity of healthy aged horses compared to healthy adult horses and found no differences.
That said some aged horses face challenges that make it difficult for them to maintain body condition, including:
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Heat and/or Cold Intolerance: Some aged horses have decreased thermoregulatory abilities and, therefore, have a hard time maintaining a healthy body condition in hot or cold temperatures.
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Herd Dynamics: If an aged horse is fed in a group situation, they could easily fall to the bottom of the pecking order, or "lose interest" in trying to fight for his share of the food, Crandell said.
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Physical Problems: A number of physical problems could limit an aged horse's ability to maintain body condition, including lameness (and a related unwillingness to travel to adequate feed sources), arthritis (and a related unwillingness to lower his head and put excess weight on his forehand), increased free radical development, chronic infection, tumors (internal or external), pituitary pars intermedia dysfunction (PPID, or equine Cushing's disease), laminitis, colic (specifically strangulating lipomas and impactions), kidney or liver disease, or dental disorders (more on that in a moment). Consult a veterinarian to ensure an aged horse is not suffering an undiagnosed medical problem; treatment could help improve his ability to maintain weight, Crandell advised.
- Dental Disease: Crandell said that while minor changes in dentition don't typically cause excessive weight loss, more serious dental problems can cause issues. She suggests consulting a veterinarian to confirm dental problems if clinical signs--including weight loss, quidding, choke, bad breath, feed packing, diarrhea, decreased rate of consumption, anorexia, or feces containing excessively long fiber pieces--become evident, as the horse could be experiencing pain associated with periodontal disease, abnormal wear patterns, missing or loose teeth, or infected teeth.
Any one or a combination of these challenges could make it difficult for aged horses to maintain a healthy body condition.
Nutrient Requirements of Aged Horses
Crandell relayed that there are no firm nutrient requirements for aged horses published. While some aged horses have the same nutrient requirements as healthy adult horses on a maintenance diet, those that suffer the effects of disease and/or poor dentition have increased requirements to maintain their body condition.
Water is the most important nutrient for horses, Crandell said, and decreased water intake could lead to colic and dehydration. There are several factors that influence water intake including water temperature, contamination, and unpalatability. To help your aged horse continue consuming adequate amounts of water, Crandell recommends keeping water at a constant temperature (not too hot or too cold); adding one to two gallons of water to the horse's concentrate and forming a mash; or adding one to two ounces of salt to the horse's daily rations.
Although studies have yielded conflicting results about protein requirements in older horses, many researchers believe aged horses might have a higher requirement if they are suffering from health problems. Healthy aged horses likely have the same protein requirements as horses consuming a maintenance diet, she noted.
Energy requirements are highly individualized and are met via the consumption of digestible fiber, starches, sugars, and fats. While some aged horses consume enough energy to maintain weight through forages, others need supplementary grain or concentrate to meet their energy requirements.
Fiber, which comes largely from forage, is an important part of the diet that keeps the horse's digestive tract functioning properly. Crandell said that it can be difficult to ensure aged horses with dental troubles consume enough forage. In these cases, she suggested using hay cubes, hay pellets, or soaked beet pulp as a forage source.
Crandell said that there has been little research completed on aged horses' vitamin and mineral requirements, but suggested that older horses might benefit from supplementation of vitamins E, B, and C to help boost the immune and digestive systems. She also suggested that older horses still in regular work will likely benefit from an electrolyte supplement.
Feeding Recommendations
Crandell said that the aged horse's diet should measure 1.5-2% of the animal's body weight and contain at least 50% forage, be it pasture, hay, beet pulp, or another alternative forage source. Those horses that need additional energy should be supplemented with grain or concentrate. Each meal should consist of no more than 0.5% of the horse's body weight, she said, so aim to feed several smaller meals throughout the course of the day.
She provided some feeding recommendations for different types of forage and grain aged horses might benefit from:
Pasture: Many older horses can maintain body condition on pasture alone during the growing season, Crandell relayed. Additional forage sources might be needed during the winter or when pasture growth slows. She noted pasture is not ideal for horses that have no front teeth, are too arthritic to drop their necks or move around, and those affected by insulin resistance and/or laminitis.
Baled Hay: The most popular forage source offered to horses, baled hay is only appropriate for horses that are able to properly chew it, Crandell said. Some aged horses might benefit from soaked baled hay, she noted. She also cautioned that horses with kidney disease should consume hay that's low in calcium, and horses with liver disease should be fed a low protein hay.
Haylage: Crandell said haylage--a high-moisture hay that has been compressed and encased in plastic within hours of harvesting and undergone the ensiling process--is great for aged horses with respiratory problems, and its high-moisture content makes it palatable and easy to chew. However, the higher moisture content means that horses need to consume a higher volume to maintain weight as opposed to baled hay.
Chopped Forage: An easy-to-chew alternative that mixes well with concentrate, chopped forage is available in both grass and alfalfa forms and can be fed wet or dry. The ability to feed chopped forage in a bucket results in less waste, Crandell said, but can contribute to feed packing and periodontal disease in some horses.
Hay Cubes: While hay cubes are a less dusty option for horses with respiratory problems, Crandell noted that they can increase choke risk if the layers they contain aren't properly broken up by the horse during mastication. She suggested soaking or covering them with water just prior to feeding to mitigate that risk. She also noted that alfalfa cubes should not be fed to horses with kidney or liver disease, as its high protein and calcium content could be detrimental to their health.
Hay Pellets: Similar to hay cubes, hay pellets can be fed wet or dry and are easier for horses with few to no teeth to digest than some other hay forms. That said, Crandell noted that hay pellets can increase choke risk in these horses, so caution should be used when feeding this type of forage. Again she noted that only grass hay pellets should be fed to horses with kidney or liver disease. She also said to switch to hay pellets gradually so the horse's microbial population can adapt to the very different forage form.
Beet Pulp: Beet pulp is best served soaked for older horses, Crandell said. She noted that beet pulp is should always be combined with hay cubes or hay pellets and not as the sole source of roughage as it does not contain the proper balance of nutrients that is normally found in other forage sources. She also noted that rinsing the forage after soaking and before feeding has been shown to reduce the amount of residual sugar horses consume. She cautioned that soaked beet pulp needs to be kept in an environment with a controlled temperature to prevent spoilage in the summer and freezing in the winter.
Cereal Grains: Some older horses can benefit from consuming cereal grains to increase the amount of calories consumed, Crandell said. These grains are very palatable, she noted, but are low in vitamins and minerals and will not provide enough micronutrients to balance a low quality forage source.
Commercially Prepared Concentrates: Supplemental nutrition is available in several different forms through commercially prepared concentrates, she said. Textured, pelleted, and extruded feeds offer improved digestibility and often have a better vitamin and mineral balance than cereal grains. Crandell also noted that there is a special class of commercially prepared concentrates specifically designed for the needs of older horses. These specialized feeds include roughage for horses that have difficulty chewing other types of forage and typically have a high protein concentration. Senior feeds can be fed wet or dry, but often have higher recommended feeding rates than normal commercial concentrates, she said.
Ration Balancer Pellets: Finally, Crandell touched on ration balancer pellets, which are designed to balance forage-only diets without added calories. These have low feeding rates, she said, and are ideal for overweight or obese horses.
Take-Home Message
Although feeding aged horses might appear a daunting task, Crandell relayed that simply individualizing each animal's diet with the appropriate forage, forage alternatives, and/or concentrates can keep senior horses at a healthy body condition. Consult an equine nutritionist or veterinarian if questions arise while developing an aged horse's feeding plan.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.