Interrelationship of Body Weight, Egg Weight, and Age at Sexual Maturity

Selection for Body Weight at Eight Weeks of Age

“…Realized genetic correlations (Table 6) were in good agreement with the correlations obtained between three and nine-week weight by Martin et al (1953). The phenotypic correlations were also consistent with those reported by Callenbach (1934) between three and eight-week weight. In addition, Maloney and Gilbreath (1962) through selection for body weight at 12 weeks of age observed a significant difference between high and low lines for body weight at six weeks of age.…”

Influence of Calcium in Laying Rations on Shell Quality and Interior Quality of Eggs

“…Regardless of calcium level in the diet, the egg weight increased from period 1 through period 10. This may be explained on the basis (Callenbach, 1934) that secretory surfaces in the region of the oviduct, where egg components are formed, become larger as the bird reaches its normal body weight. In both experiments, treatment X period interaction was found to be significant (P < 0.01) indicating the influence of dietary calcium on egg weight varied from period to period.…”

The Effect of Selection for Shank Length on Sexual Maturity and Early Egg Weight in Single Comb White Leghorn Pullets

“…Beginning egg weight and age at sexual maturity -0.7 (Lippincott, 1921); 0.3-0.6 (Atwood, 1923); 0.8 (Upp and Thompson, 1927); 0.4-0.6 (Axelsson, 1934); 0.4-0.6 (Callenbach, 1934).…”

“…Age and body weight at sexual maturity-0.5 (Upp and Thompson, 1927); 0.5 (Hays, 1933); 0.5-0.6 (Callenbach, 1934).…”