Animal Science Department


Date of this Version



Published in 3rd World Congress on Genetics Applied to Livestock Production, edited by Gordon E. Dickerson and Rodger K. Johnson, 4 vols. (Lincoln: University of Nebraska Institute of Agriculture and Natural Resources, 1986). Copyright © 1986 Board of Regents University of Nebraska.


In a CSIRO Sheep Heterosis Experiment, 387 F1 ewes were mated to either purebred, F1 or F2 rams for studying the effect of male heterosis on several lamb production traits and to investigate pro rata retention of male heterosis based on the dominance hypothesis. Evidence was found to demonstrate the occurrence of a moderate effect due to the F1 rams (versus the purebreds) and the dominance hypothesis appeared adequate to account for the pro rata retention i.e. at 50%, of heterosis in the F2 rams.