Improvements in health care and nutrition have increased the life span of horses and their number of useful years, but management decisions about an elderly equine’s well-being remain largely individualized, according to an announcement from Oklahoma State University.
“It is important to remember chronological age may differ from the animal’s physiological age, with some horses exhibiting visible signs of aging or loss of performance earlier than others,” Oklahoma State University Cooperative Extension equine specialist Kris Hiney said. “This can be affected by their previous use, animal genetics or any number of environmental factors.”
Owners should begin to monitor a horse more closely once the animal reaches its late teens, with the goal of minimizing any loss of function or vitality.
“Observe the horse for decreases in weight and body condition; loss of muscle mass, especially over the topline; alterations in fat deposition, and changes in hair coat,” Hiney said. “A careful recordkeeping system of observations should be employed, making sure to include bimonthly observations of the horse’s body condition score, bodyweight and a photographic record of the horse.”
Additional measurements like neck or belly circumference also may assist with detection of disease states, such as insulin resistance.
“It’s easy to miss changes when observing a horse every day,” Hiney said. “As the horse ages further, increase the frequency of recording observations to once a month or even every other week for aged animals.”
Predictable changes with aging horses have much in common with aging people, Hiney said. The immune systems are more easily compromised in older horses versus younger horses. They lose elasticity in their tendons and ligaments. Exercise just does not come as easily as when they were younger. Given the likelihood of immune system impairment, equine owners should consult with a veterinarian about the proper vaccination protocol for each older horse, with a special consideration made for its lifestyle.
“Consider increasing the level of biosecurity for older horses, treating them similar to the very young and avoiding contact with other horses that travel frequently,” said Dr. Dianne McFarlane, equine veterinarian with the Oklahoma State University Center for Veterinary Health Sciences.
In addition, an older horse’s immune system can be sustained by proper feeding of antioxidants such as copper, selenium and vitamin C. Keep in mind that, as a horse’s immune system declines, the animal is less able to withstand parasitic infection.
“Greater fecal egg counts have been observed in both older horses and horses with equine pituitary pars intermedia dysfunction (PPID),” McFarlane said. “More frequent fecal egg count determinations are warranted with these animals to verify the level of parasite load. Be sure to conduct fecal egg counts to coincide with the period of time of typical egg shedding to get the most accurate information.”
Maintaining mobility and comfort for an older horse is a key management consideration, as 50% of horses over the age of 15 experience osteoarthritis. Hiney warned that equine owners can easily overlook the condition and may miss a chance to intervene in a timely manner.
Numbers tell the tale
In a study of management practices, owners of older horses recognized lameness in only 23% of cases, compared to 51% diagnosed by veterinarians. The same study showed that the owners recognized hoof abnormalities only 27% of the time, compared to veterinarians diagnosing the problem 80% of the time.
“Maintaining a consistent level of fitness or exercise will help with mobility,” Hiney said. “Be sure to provide longer warmup and cooldown periods, as the older horse is an aging athlete.”
Therapies for reduced mobility may include local treatment of the joints, physiotherapy, farrier care such as orthopedic shoes, joint supplements, omega-3 fatty acids or anti-inflammatories to keep the horse moving.
“Consider the older horse’s housing requirements,” Hiney said. “The horse should have a comfortable place to lie down from which they can also easily rise and get back upright.”
Hiney and McFarlane recommended that equine owners pay attention to subtle changes in movement or behavior that may indicate that the horse is in pain, such as a horse that becomes reluctant or disobedient when supporting a hoof.
“Many aged horses with painful feet or chronic foot abscesses may have PPID,” McFarlane noted. “Frequent or increased bouts of laminitis or soreness of feet are seen in 30% of equines with PPID. Furthermore, between 20% and 30% of older horses will develop PPID, which is often overlooked in the early stages.”
Classic signs of PPID include failure to completely shed or the presence of patches of longer hairs on the abdomen and legs. Horses may literally change shape as well, with increased fat observed particularly over the crest of the neck, the tailhead and in the mammary region. In addition, horses with PPID may exhibit a loss of muscle mass over the top line and perhaps even develop a potbelly as the disease progresses.
“It’s not unusual for a horse with PPID to exhibit an increased level of thirst and a decreased ability to thermoregulate,” McFarlane said. "PPID is confirmed by a veterinarian through monitoring alterations in hormones.”
McFarlane and Hiney emphasized that there is no reason to automatically consider an older horse as unusable. “Horses just need more attention past a certain age,” Hiney said.