With the advent of ivermectin-based dewormers in the late seventies, horse owners could control the large strongyle. Migration of this extremely destructive strongyle's larvae up the mesenteric arteries and the ensuing damage was largely responsible for limiting the horse's life to around the 20-year mark. This limit on a horse's life meant we rarely had to deal with geriatric diseases of horses. Since the use of this dewormer, the incidence of life-threatening infarction of the blood supply to the bowel has steadily declined. Horses can now be expected to live well into their 30s or beyond, depending on many factors, including the level of health care. However, with the increase in older horses we are seeing more problems that result in weight loss despite continuing a good diet.

This article discusses diagnosis of common problems that cause weight loss and lists some of the most common problems, lists treatment options, and provides links to articles with detailed information.

A horse greater than 20 yr of age should be considered a geriatric animal. Some problems are recognizable only by history, particularly unexplained behavioral changes like decreased feed intake. Detailed information on these topics should be taken:

• feed amount and quality
• pasture and housing conditions
• past disease problems,
• deworming practices
• changes can be very important:
  • in the environment
  • pasture companions
  • feed and water consumption
  • urination frequency

Many geriatric patients can be safely fed a maintenance ration designed for all horses without modification. In cases where the horse has loss of body condition and no other existing disease, the horse should be fed a very palatable, easily masticated, easily digested, dust-free diet that has a higher protein content (12-16%), maintenance levels of calcium (1%), and slightly elevated P content (0.4 - 0.65%), maintaining a Ca:P ratio of close to 1.5:1.

Older horses may be more sensitive to cold and adverse conditions. Be sure the horse always has shelter to get out of the wind and rain when cold. They may also not compete as aggressively for food, so they should be fed separately from their pasture mates. Older horses may not adapt as rapidly to change, particularly when moved into a new situation. Changes should be made slowly the horse carefully monitored for successfully coping with the new situation.