There should be no difference than from grazing grass pasture, so as long as the horse is not a chronic founder or has a insulan resistance issue then laminitis is not the issue. However, wheat is not recommended for horses because it carrys a endophyte that can sometimes be toxic to horses. I know one guy who killed 7 of his horses almost instantly by feeding them wheat screenings. I also though know another guy who round baled a alfalfa seeding with a lot of volunteer wheat in it and sold the bales to several horse owners and there was no problem. In general, wheat and rye are not advised for horses. You could have the wheat tested by doing a scissor clip and sending them in.