FEED BEEF - MGA in MFA Beef Feeds

   MGA in MFA Beef Feeds

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    What is MGA?

MGA is the abbreviation for the compound melengestrol acetate.

    What Is It For?

The compound is a feed additive labeled for increased rate of weight gain, improved feed efficiency and suppression of estrus (heat) in heifers fed for slaughter. In addition, with special instructions, the compound can be utilized in a program to synchronize heat in heifers for a tighter breeding schedule.

It is classified as practically non-toxic and it has a wide margin of safety in cattle and other species when used at recommended doses.

    How Does It Work?

MGA improves performance by the natural steroid effects of its progesterone-like structure, and by suppressing estrus activity that can be detrimental to feedlot performance.

    How Much Do Heifers Need to Receive Its Benefits?

MGA should be thoroughly mixed in the supplement of feedlot heifers to provide 0.3 to 0.5 mg of melengestrol acetate per head per day.

For estrus synchronization programs, constant daily intakes of 0.45 to 0.5 mg per head per day for 14 days give a high degree of estrus suppression. Feeding 4 lbs. Cattle Charge Estrus Control Ration per head per day will provide .5 mg MGA/hd/day.

    What Else Can I Feed with MGA?

MGA may be legally fed in the following combinations:

  • MGA + Rumensin

  • MGA + Rumensin + Tylan

  • MGA + Rumensin + Optiflex

  • MGA + Rumensin + Tylan + Optiflex

  • MGA + Bovatec

  • MGA + Bovatec + Tylan

  • MGA + Tylan

  • MGA + Terranycin

  • MGA + Zilmax

  • MGA + Rumensin + Zilmax

  • MGA + Rumensin + Tylan + Zilmax

Each combination has specifically approved levels related to other official and legal claims.

    Are There Safety Cautions to Observe?

This product is only for use in heifers being fed for slaughter and is not effective in spayed heifers or steers.

There is no required withdrawal period for MGA prior to slaughter. Withdrawal periods of three to five days or more should be avoided to prevent the possibility that the heifers may come into estrus at loading time.

For more detailed information, contact an MFA veterinarian.

You can also contact Janice Spears at for more information.

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