Feeding the Senior Horse

When is a horse considered “aged” or a “senior” concerning nutrition? At 15? At 20?  Many nutritional studies on older horses have arbitrarily used 20 years as the threshold for “aged” or “senior.” The NRC 2007 suggests three ways “old age” can be defined, which are listed below.  

  1. Chronologic – number of years from birth
  2. Physiologic – the decline in physiologic functions as the threshold for old age
  3. Demographic – reflects an age-group population within the whole horse population.

Senior Horse

The best way to define this population of horses may be a combination of chronological age and physiological signs of aging. As horses age, they undergo several changes that affect how and what you should feed them. Some physical signs of aging are:

  1. Dental disease or loss of teeth can cause chewing to become difficult and even ineffective. Worn incisors will make it difficult for horses to graze. Worn or damaged molars cause difficulty grinding feed. Worn molars cannot chew hay and the horses have a difficult time swallowing and digesting the hay. Alternative forges like hay cubes and pellets can feed horses with poor teeth. Sugar beet pulp and soybean hulls can also be fed to increase fiber intake. Grains, if fed, should be well processed (extruded, pelleted, micronized, or steam flaked).
  2. The hindgut loses some of its ability to ferment fiber. A reduction in fiber fermentation means that older horses receive less nutrients from forage resulting in higher quality forages being required. Alfalfa hay and good quality grass hays are preferable to stemmy and mature hays with tougher fiber to ferment.
  3. The small intestine loses some function - Older horses find it harder to digest protein in the small intestine. In addition, some older horses with reduced liver and kidney function find it difficult to excrete waste products associated with overeating protein. Therefore, the key to feeding older horses is to use high-quality protein from alfalfa, soybean, and canola without oversupplying their requirements. Aged horses lose body condition and muscle along the topline due to less efficient processing of certain nutrients in the older horse, most notably protein. Commercial senior feeds have improved the amino acid balance to help reverse such changes.
  4. Older horses are prone to Cushing’s Syndrome. Cushing’s horses often lose muscle mass to a higher degree than a normal aging horse. Again, improving the amino acid balance (not just feeding MORE protein) can help reverse the loss of or maintain muscle mass.
  5. One of the most apparent changes in an older horse is loss of mobility. Maintaining these horses in pastures/paddocks where feed and water sources are reasonably close together will help so the old ones do not need to travel long distances. If the senior horse is maintained in a herd, they should be evaluated continuously because most will fall down the pecking order and are more easily bossed around. This results in the aged horse eating less feed.
  6. Loss of body score (body condition or body fat) is related to the above issues. Many older horses require more calories from highly digestible fiber sources like beet pulp, soy hulls, and dehydrated alfalfa meal. In addition, dietary fat helps with weight loss.

The total diet, hay and grain combined (dry matter basis), should contain 12-14% high quality protein, 03. – 0.4% phosphorous, 0.6 – 0.8% calcium and added Vitamin C.

  • Aged healthy horses with a BCS of 5 to 7 require 1.5-2.0% of their BW DM/day of good quality grass or legume mix hay. Typically, no grain is necessary but if desired or needed, choose one with restricted starch/sugar and contains added fat (4-7%). Forage-based pellets or cubes could replace 10 to 50% of the long stem/chopped forages in these horses.
  • Aged, healthy, thin horses with a BCS < 4 should be fed 1.5-2.0% BW DM good to excellent quality grass or grass/legume mix hay. A grain-based concentrate formulated for the aged horse with 12-14% CP and 4 to 7% fat should be fed at 0.5-1.0% BW. Starch and sugar should be minimized if the horse is prone to laminitis or has PPID. Forage-based pellets or cubes can replace 10-50% of the long stem/chopped forages.

Horse with Cushings

Management suggestions

  • If the horse can still eat hay:
    • Use higher fat or heat-processed feed (like extruded or pelleted). Extrusion/heat-processing increases foregut digestibility.
    • Assure adequate intake of all other vitamins and minerals.
    • Offer free-choice vitamin/mineral mix designed for horses eating grass hay.
  • If the horse cannot eat hay (leaves wads of hay by feeder):
    • Feed complete feed with highly digestible fiber. Fiber sources include beet pulp, dehydrated alfalfa meal, and soy hull.
  • Assure high-quality sources of protein, vitamins, and minerals.
  • If the horse cannot chew well, one can make a slurry of complete (or) extruded feed.
  • Feed at least three times a day.
  • Total intake should be 1.5 – 2.0% of the horse’s body weight (15 – 20 lbs. For 1,000 lb. Horse)

Old horses are valuable and have a lifetime of experience under their ‘girth’. We want to do our best to keep them around as long as possible, which requires good veterinary, farrier and dental care. A solid foundation of good nutrition is necessary for maintaining our old friends.

Photos credit: Adobestock