power fuel and weight gain

I have a shorthorn steer I taped at around 975 pounds last week. My county fair is in 2 and a half weeks. 900 is our min weight but I'm concerned about any weight lost with stress. He's been a really slow and poor grower the whole time I've had him. I've been trying hard to push him with what I can, but recently saw the supplement power fuel. Would there be any point in feeding that with the amount of time I have left? If not are there any suggestions to get as much weight on him as possible by then? Thank you!