CHALLENGE 5: BOLSTER IMMUNITY

Scientists suspect that like their human counterparts senior horses experience decreased immunity to some diseases as they age. In some cases this may make them more likely to contract a disease or they may be harder hit if they do. In fact, research has shown that senior horses who become sick as a result of West Nile virus infection are more likely to die than are younger horses.

Researchers are looking into the effects of aging on immune function, and studies are under way to determine whether senior horses may benefit from vaccines formulated with new adjuvants (drug modifiers that stimulate response to a vaccine antigen), or from protocols that call for increasing the frequency of vaccination.

Until we know more, your best defense is to work closely with your veterinarian to tailor a vaccination program based on your horse’s geographic location and risk of exposure. Be sure to let your veterinarian know of any changes in your horse’s routine, such as a move to a new barn, or if he will be exposed to horses who travel.