Our horses are living longer, healthier lives, thanks to advances in equine medicine and nutrition. Nonetheless, most horse owners ultimately find themselves taking a long, hard look at their aging horses, assessing quality of life, and making difficult decisions about euthanasia. Researchers have examined the top reasons for death and euthanasia in older horses, shedding light for the first time on what medical conditions actually cause death or necessitate euthanasia in aged equines.

"Previous studies have suggested that one of the most common reasons that horse owners choose to have their geriatric horses, which are those over 15 years of age, euthanized is due to ‘old age,’" said Joanne Ireland, BVMS, MRCVS, a research assistant at the University of Liverpool in England.

However, because "old age" is not a specific cause of death, Ireland and colleagues launched this retrospective study–the first examining medical causes of death in senior horses–which involved surveying owners of geriatric horses.

Key findings of the study were:

  • Complete data was collected on 118 horses that had died or were euthanized, of which the majority (94%) were euthanized;
  • The most common reasons for euthanasia were lameness (24%) and colic (21%);
  • An association between an increasing number of owner-reported clinical signs that limited normal daily activities and increased risk of mortality was observed;
  • Veterinary advice was important in owner decision-making regarding euthanasia of cases of colic or other acute illnesses, while poor quality of life was considered an important factor where euthanasia was due to chronic diseases or lameness;
  • Not surprisingly, increasing age was associated with the likelihood to die or be euthanized. (For example, horses more than 30 years old were five times more likely to die or be euthanized than horses between 15 and 19 years of age); and
  • Underweight horses were more likely to die or be euthanized than horses in good body condition.

According to Ireland, "Geriatric horses now represent a substantial portion of the equine population."

For the first time, owners and veterinarians have access to information on the common medical causes of death of senior horses. An understanding of what conditions are commonly fatal to older equines can help owners and veterinarians monitor seniors vigilantly for signs of ailments that might require immediate and accurate treatment.

The study, "Factors associated with mortality of geriatric horses in the United Kingdom," will be published in the September 2011 edition of Preventative Veterinary Medicine. The abstract is available on PubMed.