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When is a horse considered a "senior"?

When it comes to seniors, one of the most commonly asked questions is, “At what age is my horse a senior?” The answer, of course, depends on the horse. Horses, like people, age as individuals, and there is no hard and fast rule about when a horse is officially a senior citizen. The National Research Council (2007) suggests that while 20 years is an estimate of what is considered old age, there is considerable individual variation. A combination of chronological age (age in years) and physiological characteristics are best used for determining whether a horse is a senior (NRC 2007). However, many horses have some signs of aging around 20 years. Some of those changes may be visible, such as grey hair around the face or loss of muscle tone, while others may not be so obvious, such as hormonal changes or changes in the immune system.


 

As horses age, they typically fall into one of four categories:

  1. Young at Heart – generally healthy
  2. Aged with a tendency to gain weight/obese
  3. Aged with a tendency to lose weight/underweight
  4. Geriatric – other health problems involved

 

Still, one may notice that it is harder for a horse to work or compete at a certain level than it used to be. It may take longer to warm up for work, and it’s harder to cool down afterwards.

Aging is usually associated with changes in strength, body composition and general physiological function, but how much of these changes occur is very much dependent on the individual (Ralston and Harris, 2013). We do know that older horses have a harder time regulating body temperature (McKeever, et al., 2010), and are more easily affected by extreme temperatures (hot or cold). Exercise capacity decreased, recovery time increases (Betros et al., 2002) and there is a natural change in the endocrine system (Malinowski et al., 2006) that can be mitigated to some extent by maintaining a light training program (Liburt et al., 2014). Recent research has also suggested that a decrease in microbial diversity in the hindgut may occur as a result of age (Dougal et al., 2014). Again, some of these changes are easily observable while others are not.

We love our seniors, no doubt. The 2015 USDA APHIS survey put the population of horses over the age of 20 years at 11.5% of the equine population, up from 7.4% in 1998. We know more about how horses age, and how to better care for them. One of the most important things we can do as guardians of our animals is to know what is normal and what is not. Note changes, work with a veterinarian to maintain regular healthcare, and adjust exercise regimens as necessary (according to ability and ambient temperature). Diet need not change unless there is a reason, for example, weight gain/loss or endocrine disease. I’ll leave you with this recommendation: Know Your Horse! Keep track of weight, changes in behavior, movement and attitude. Maintain open lines of communication with your veterinarian, and of course your friendly BUCKEYE™ Nutrition professional nutritionists! We’re here to guide your horse’s nutrition through every stage of life, so ask us when you need help.

The old adage, “Use it or lose it” holds very true for horses as well as their human caretakers – having a job, even if low level, helps keep the body moving, and the mind stimulated. Make accommodations for any changes a horse experiences, but don’t count them out just because the years add up!


References:

Betros, C.L., McKeever, K.H., Kearns, CF., Malinowski, K. 2002. Effects of ageing and training on maximal heart rate and VO2max. Equine Veterinary Journal. 34(S34):100-105.

 

Dougal, K., de la Guente, G., Harris, P.A., Girdwood, S.E., Pinloche, E., Geor, R.J., Ninelsen, B.D., Schott, H.C., Elzinga, S., Newbold, C.J. 2014. Characterisation of the faecal bacterial community in adult and elderly horses fed a high fibre, high oil or high starch diet using 454 pyrosequencing. PLoS One 9(20:e87424.

 

Liburt, N.R., McKeever, K.H., Malinowski, K., Smarsh, D.N., Geor, R.J. 2013. Response of the hypothalamic-pituitary-adrenal axis to stimulation tests before and after exercise training in old and young Standardbred mares. Journal of Animal Science. 91(11):5208-5219.

 

Malinowski, K., Shock, E.J., Rochelle, P., Kearns, C.R., Guirnalda, P.D., McKeever, K.H. 2006. Plasma beta-endorphin, cortisol and immune responses to acute exercise are altered by age and exercise training in horses. Equine Veterinary Journal Suppl. 36:267-273.

 

McKeever, K.H., Eaton, T.L., Geiser, S., Kearns, C.F., Lehnhard, R.A. 2010. Age related decreases in thermoregulation and cardiovascular function in horses. Equine Veterinary Journal. Nov (38):220-227.

 

National Research Council (NRC). 2007. Unique aspects of equine nutrition. In: Nutrient Requirements of Horses, 6th Ed. National Academies Press, Washington, DC. pp. 235-267.

 

Ralston, S. and Harris, P. 2013. Nutritional consideration for aged horses. In: Equine Applied and Clinical Nutrition. Geor, R.J., Harris, P.A and Coenen, M., Eds. Saunders Elsevier, London. pp. 289 -303.

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