I look at it like this....my local feed store bombards me with choices; weight boosters, senior feeds, joint supplements, feeds with added vitamins. I'm always asking myself which feed is best? What do I get because I have more than 1 horse? I know obviously each horse requires vitamins, minerals and proteins but not every horse needs the same amount of grain so I finally I started using a custom feed blend of Beet Pulp, Soybean meal, crimped oats or barley and a supplement like Lampley's A-Z. This way I can regulate how much vitamin and minerals my guys are getting. When I feel I need to increase protein I just add some flaxseed meal. Sometimes I add hay cubes for variety.