Department of Animal Science


Date of this Version



Published in Nebraska Beef Cattle Report 1998, published by Agricultural Research Division, University of Nebraska Cooperative Extension, and Institute of Agriculture and Natural Resources, University of Nebraska–Lincoln.


Estrous synchronization rate and conception and pregnancy rates to AI were evaluated following three estrous synchronization protocols for beef cattle. During 1995 and 1996, heifers and cows (n = 379) received either: 1) melengestrol acetate (MGA) for 18 days plus an injection of progesterone and estradiol in oil 7 days before end of treatment; 2) MGA for 17 days; or 3) two injections of PGF2&#;&#;&#;10 days apart. The greatest pregnancy rates (number conceived/number treated) among both anestrous and estrual females were achieved following treatment with MGA and an injection of progesterone and estradiol.