no idea how much but a friend has had her dressage youngster on this all winter(is on a yeard owned by a D&H sponsored rider so got it before it came on to the open market) and is very happy with it-horse has bulked out and put a shine on his coat.
iv found linseed to be working very well on my TB, but if i suddenly couldnt get it, id try build and glow based on friends results.