Performance data from a Polled Hereford
herd selected for improved feed conversion
were used to calculate a variety of genetic parameters. Heritabilities were .14 for weaning
wt, .18 for maternal weaning wt., and .19 for
milk production. The genetic correlations were
–.10 between weaning weight and maternal
weaning weight and 0 between weaning weight
and milk production. However, the genetic
correlation between maternal weaning weight
and milk was . 99, indicating they are essentially
the same trait. Milk EPDs published by most
breed associations are calculate d as the maternal
weaning weight. Our study strongly supports
this method of estimating an animal's genotype
for milk production.
