University of California

Responses of feedlot heifers to MGA feeding and Synovex-h implanting


C. A. Perry
D. Addis
H. Strong
R. G. Loy
A. W. Brant
T. M. Little

Authors Affiliations

C. A. Perry is Livestock Farm Advisors, Los Angeles; D. Addis is Livestock Farm Advisors, Los Angeles Riverside counties, respectively; H. Strong is Extension Animal Husbandman, Emeritus; R. G. Loy was Assistant Professor, Department of Animal Husbandry University of California, Davis; A. W. Brant is Extension Food Technologist University of California, Davis; T. M. Little is Biometrician, Agricultural Extension Service, U. C., Riverside.

Publication Information

Hilgardia 22(4):10-12. DOI:10.3733/ca.v022n04p10. April 1968.

PDF of full article, Cite this article


Synovex-H has consistently stimulated daily gain and improved feed efficiency of feedlot heifers. However, this hormone does not inhibit the estrus cycle in heifers (which is responsible for excessive animal activity restricting feedlot performance during periods of hot weather). Melengestrol acetate (MGA), a new, synthetic high-potency hormone compound had previously been reported to increase feeding performance when added to the daily ration—and in the two tests reported here, also effectively controlled estrus. Both MGA and Synovex-H significantly increased daily gain and improved feed efficiency over the control animals. The MGA-fed heifers shrank less in transit than either the Synovex-H or control groups, although dressing percentage was about the same for all groups. Tenderness and fat content of rib and bottom round steak were not affected. The size of the rib eye from the MGA-fed heifers was slightly smaller than from the control or Synovex-H groups.

Perry C, Addis D, Strong H, Loy R, Brant A, Little T. 1968. Responses of feedlot heifers to MGA feeding and Synovex-h implanting. Hilgardia 22(4):10-12. DOI:10.3733/ca.v022n04p10
Webmaster Email: wsuckow@ucanr.edu