You might not have heard the word “immunosenescence,” but if you’re caring for an older horse, you’re dealing with it daily. It seems that aging isn’t just a matter of time marching on for the horse as a whole; the immune system itself is also aging biologically via this process.

As horses age, their systemic immunity declines, which can contribute or lead to increased prevalence of cancer, autoimmune and chronic diseases, poor response to vaccination, and increased susceptibility to common infectious diseases.

Amanda A. Adams PhD, a researcher at the University of Kentucky Gluck Equine Research Center, in Lexington, spoke on the topic at the 2016 American Association of Equine Practitioners convention, held Dec. 3-7 in Orlando, Florida. She explained research findings regarding how aging horses respond to vaccinations, inflammation, and parasites.

Another term you might not have heard is “inflamm-aging,” or chronic, low-grade inflammation that occurs with age. We normally think of inflammation as being acute, for instance, as with a swollen ankle. With treatment, that acute inflammation resolves in days, and the swelling subsides