Lacking Energy

My dressage horse seems to tire very quickly during training.
Dressage horses work hard and should be fed a mixture of energy sources for best performance. These include quality digestible fibre and oil for slow release sustained energy output and some starch for fast release available energy. Badminton Dressage Mix has been formulated to supply all these optimal levels and help maintain performance. Dressage horses are also subject to additional stress when travelling and competing, so Badminton have added a digestive enhancer, EquiMatrix, to Dressage Mix, which helps support the horse's immune system during the long competition season.

I have a 3-Day Event horse that seems to lack sparkle. What can I feed him to give him some fizz?
Badminton Competition Mix has been formulated to provide hard working horses with sources of quick release energy. It also contains high levels of vitamins and minerals to help maintain optimum performance. It is also fully guaranteed for competition work.