A recent study indicated that diet can have an effect on your horse’s behavior. A graduate student at Virginia Tech performed a study on the horses in the university’s riding program.  The study involved using different levels of fat and starch and determining behavior.  The Horse publication indicates that in the study 20 riding horses were split into five groups of four horses. Each group received a different starch-to-fat ratio in their diet ranging from 7.1% to 14.3% starch.  All horses were fed twice daily for the 21-day duration of the study, housed in individual stalls and ridden in the university’s riding program, which consisted of beginner to advanced equitation (riding) and hunter/jumper.  All riders and instructors were blinded to the diet so they did not know which horses were being fed which diets.  The horse’s behavior was evaluated while being caught, led and groomed as well as while being ridden.  Reaction to leg aids, relaxation and submission were also noted. Blood samples were taken before and after the 21-day trial. 

Results indicated that the different diets had no significant effect on the horse’s body weight or condition score, and this was expected as all diets were balanced for body weight and body condition score.  However, horses on high-starch low-fat diets had higher behavior reactivity scores from both instructors and riders.  Horses on low-starch diets became better behaved over time and those on high-starch diets were less well behaved.  You may have always heard that high-grain diets make horses hotter and more difficult to handle, and although most nutritionists say this is not the case, this study seems to indicate that horses on high-starch diets are more difficult to handle as these diets have a negative effect on behavior.