Behavior of horses is affected by soy lecithin and corn oil in the diet.

To test the hypothesis that dietary fats may improve tractability of horses, the effects of four total mixed diets on behavior were compared. The control diet (CON) contained chopped hay, corn, oats, beet pulp, molasses and a mineral mix; the three test diets contained an additional 10% (by weight) corn oil (CO), soy lecithin-corn oil (SL-CO), or soy lecithin-soy oil (SL-SO). Eight horses were fed each diet in random order for four 3-wk periods. Behavior was observed during the last week of each feeding period. Spontaneous activity was evaluated using a pedometer and was less in horses fed SL-CO than in controls (P = .022). Reactivity was evaluated as responses to pressure, loud noise, and sudden visual stimuli. Compared with results for control horses, reactivity was less in horses fed SL-CO during the visual stimulus test (P = .036), in horses fed CO in the noise test, the pressure test, and the visual stimulus test (P = .093, .108, and .116 respectively), and in horses fed SL-SO during the visual stimulus test (P = .108). These results provide the first quantitative evidence that dietary fats reduce the activity and reactivity of horses.