U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska


Date of this Version


Document Type



Published in Beef Research Program Progress Report (1982) No. 1: 16-17


Historically, beef cattle record of performance programs have by necessity expressed variation as deviations or ratios from herd means because differences between herds are believed to be large primarily because of environment. To the extent differences between herds are genetic, this procedure underestimates or overestimates breeding values of individuals relative to breed average depending on whether they are produced in herds of above or below average genetic merit for a breed. We conducted this study in cooperation with the American Angus Association and the American Polled Hereford Association, and designed it to separate and evaluate the relative importance of between-herd and within-herd sources of genetic variation for birth, growth and carcass characteristics.