MGA®

For: Beef Cattle - Available in: United States

MGA® (melengestrol acetate) medicated feed additive is an in-feed product for the suppression of estrus (heat) in heifers confined for slaughter or kept for breeding. In heifers confined for slaughter, MGA can be mixed with feed to increase rate of weight gain and improve feed efficiency.

Indications

For increased rate of weight gain, improved feed efficiency and suppression of estrus in heifers fed in confinement for slaughter, and for suppression of estrus in heifers intended for breeding.

Available as

Feed Additives

For use with

Beef

Pack sizes

50-pound bags

17.5-L Liquid Drum

How It Works

When fed to heifers in confinement, MGA® suppresses estrus and prevents ovulation, which will help improve weight gain and feed efficiency.

What Is It For?

Key Features:

  • Contains melengestrol acetate (MGA) for mixing with nonmedicated feed.
  • MGA® 500 is used in liquid feed. MGA® 200 is used in dry feed.
  • Provides increased rate of weight gain, improved feed efficiency and suppression of estrus in heifers fed for slaughter and for suppression of estrus in heifers intended for breeding.
  • MGA is approved for the following combinations:
    • Bovatec® (lasalocid)
    • Bovatec and tylosin phosphate
    • Bovatec and Aureomycin® (chlortetracycline)
    • Actogain® 45 (ractopamine hydrochloride), monensin and phosphate tylosin
    • Monensin
    • Monensin and tylosin phosphate
    • Oxytetracycline
  • MGA has zero-day withdrawal.
How Effective Is It?

In a study, heifers were fed MGA® or their ration alone from Day 28 to slaughter. Those fed MGA demonstrated:1

  • Increased final body weight by 29 lbs.
  • Increased carcass weight by 19 lbs.
  • 2.4% improvement in feed efficiency
  • Improved quality grade distribution
Safety Information

WARNING: Not for human use.

PRECAUTIONS: Not effective in steers and spayed heifers. Heifers Fed in Confinement for Slaughter: Withdrawal periods of three to five days or more should be avoided to prevent the possibility that the heifers may come into estrus (heat) at loading time. Heifers Intended for Breeding: Do not exceed 24 days of feeding of melengestrol acetate to heifers intended for breeding. A reduced conception rate can be expected if heifers are bred at estruses observed within 1 to 12 days after withdrawal of melengestrol acetate, whereas heifers bred at subsequent observed estruses are expected to have normal conception rates.

Do not use Actogain in animals intended for breeding. Refer to label for complete directions for use, precautions, and warnings.

Do not use Bovatec in calves to be processed for veal. Do not allow horses or other equines access to feeds containing lasalocid, as ingestion may be fatal. Feeding undiluted or mixing errors resulting in excessive concentrations of lasalocid could be fatal to cattle and sheep.

Do not use Aureomycin in calves to be processed for veal.
Caution: Federal law restricts medicated feed containing this veterinary feed directive (VFD) drug (Aureomycin) to use by or on the order of a licensed veterinarian.
A VFD is also required for the feeding of MGA in combination with tylosin or oxytetracycline.
References
1 Perrett T, Wildman BK, Jim GK, et al. Evaluation of the Efficacy and Cost-Effectiveness of Melengestrol Acetate in Feedlot Heifer Calves in Western Canada. Vet Ther. 2008;9(3):223-240.