horse not eating - heavy exercise

Question
hello ma'am. how are you? a question for you.

my dad owns a filly at our local racetrack. my groom told me that whenever horses are exercised heavily, they dont eat their feed well for two to three days. may i know why?

Answer
Hello Caine,

Generally, horses who work more end up eating more.  The fact that your filly has decreased dry matter intake can be cause for concern, as it may eventually lead to weight loss and impaired performance.  There may be a few underlying factors at play, but I would start by looking at the filly's water intake and by determining if a high-starch diet is leading to overall fatigue.  Exercising horses have an additional requirement for water lost through rapid respiration and sweating while exercising.  If horses are deprived of water, or can not sufficiently rehydrate after exertion, they will eat less...especially if the feed is dry.  Ensure that the horse has unlimited access to water as soon as she has cooled down after exercise.  That is when horses are the thirstiest and likely to properly rehydrate.  High starch diets can, when a horse is exercising intensely, lend to acute fatigue in horses.  In short, the acid-base balance is tipped in extreme fatigue due in part to heavy starch loads.  Fatigue doesn't just affect the horse in her demeanor, it affects the horse at the cellular level.  This metabolic disturbance can have a deeper effect on metabolism.  Secondary to ensuring adequate water intake, ensure that the horse's diet contains a variety of energy sources that both meet its requirements and maintain a healthy metabolism.

Thanks, Corlena