Feeding nutrients beyond those that are necessary to balance the stallions diet have not been show to improve libido.
Recent research has revealed the benefits of supplementing stallions with Omega 3 fatty acids. Docosahexaenoic acid (DHA; an Omega 3 fatty acid) has been shown to significantly increase the number of sperm per ejaculate, increase motility of sperm and decrease dead and abnormal sperm compared to non-supplemented stallions.