Abstract
Estimates were calculated from both adjusted and unadjusted weights of 1,584 cows in 17 representative Virginia Hereford herds. Adjusted weights were adjusted for year, herd, flesh condition, sire of cow, age, days postpartum and the interactions of year × age and year × condition. Variations of this basic model were used to analyze several subsets of the data, however, because the sires of some cows were unknown, there were repeat observations on some cows in two herds, some cows did not wean calves the years weights were taken or because of computer inability to handle the large number of sire groups. Heritability estimates ranged from 0.52±.16 to 1.00±.16. The lowest h2 was obtained from an indirect method (Harvey, 1970 as modified by Bailey et al., 1971) based on the sire component of variance calculated from data set 3 consisting of 854 cows by 210 sires. This low estimate probably resulted from a poor estimate of the sire component of variance. Copyright © 1973. American Society of Animal Science . Copyright 1973 by American Society of Animal Science.