Federal Register Correction: In 21 CFR, Parts 500 to 599, revised as of 4/1/11, on page 490, in Sec. 558.500, (e)(1)(i) FDA reinstates it as follows; Sec. 558.500 Ractopamine in grams/ton 4.5 to 9 For increased rate of weight gain, improved feed efficiency, and increased carcass leanness in finishing swine, weighing not less than 150 lbs, fed a complete ration containing at least 16% crude protein for the last 45 to 90 lbs of gain prior to slaughter. To view this correction, click here.