Genetic Variation and Covariation in Broiler Body Weight and Breast Width

BODY weight has been a trait of primary interest to broiler strain breeders for a number of years. In addition, considerable attention has been paid to body conformation as measured by breast plumpness, angle, or some other measuring device. Heritability estimates of broiler body weight are generally considered to be in the range where individual selection is most efficient in improving this trait, but little information is available on the heritability of breast angle. Similarly, little is known about the interrelationship of these two traits. Although many studies have shown that body conformation is heritable (see Jull, 1952, for a review of these studies), only one study to date has reported heritability estimates of this trait. Lerner, Asmundson and Cruden (1947) calculated a heritability estimate for breast width at 12 weeks of age of 0.2. They also found a slight positive genetic correlation between breast width and body weight in …