MELENGESTROL ACETATE (addendum)

摘要

Melengestrol acetate (17a-acetoxy-6-methyl-16-methylene-4,6-pregna-diene-3,20-dione; MGA) is a synthetic progestogen that is active after oral administration. It is administered as a feed additive to female beef cattle (heifers) to improve the efficiency of feed conversion, promote growth and suppress estrus. The range of approved doses is 0.25-0.50 mghe ifer daily, and it is fed for the duration of the fattening/ inishing period, usually 90-150 days. MGA has been reviewed previously by the Committeeat its fifty-fourth, fifty-eighth, sixty-second and sixty-sixth meetings (Annex 1, references 146, 157, 169 and 181). An acceptable daily intake (ADI) of 0-0.03 g kg body weight (bw) was established at the fifty-fourth meeting of the Committee.