I started both boys on a single ounce; no sense in rocking the boat too much. Speedy likes anything I feed him and never has an adverse reaction. Izzy's the one that I need to watch. When I rode him yesterday morning, after a single ounce of Nutra-Flax, he seemed fine, and was maybe even a bit behind my leg. He got another ounce yesterday, so today's ride should offer more data.
Given that Izzy did well on flaxseed oil, I can't imagine the ground version will be any different. While Cool Calories didn't work for him, I am hopeful that the Nutra-Flax will give him those extra calories he needs without turning him into a rocket.