Regression of Abdominal Fat in Broilers on Abdominal Fat in Spent Parents on Severe Feed Restriction

A commercial meat-type female line was maintained on the restricted feeding program recommended by the breeder to 5 months of age. Sixty-five pullets were then placed in individual cages and fed throughout laying to 14 months of age at the rate of 12.75 kg of feed per 100 hens per day. Egg production was measured per hen between 7 and 9 months of age. A total of 418 male and 359 female pedigreed progeny were produced by artificially inseminating the hens using semen from a commercial meat-type male line. The male broilers averaged .98 ± .02 abdominal fat percentage body weight with a coefficient of variation of 50%. The female broilers averaged 1.25 ± .03 abdominal fat percentage body weight with a coefficient of variation of 48%. Heritability estimates for abdominal fat percentage body weight of broilers were .72 ± .21 for males and .23 ± .20 for females. Genetic correlations between body weight and abdominal fat weight in broilers were .23 for males and .64 for females, but there was essentially no genetic correlation between body weight and abdominal fat percentage body weight, which was 0 for males and −.12 for females. The spent dams and sires were sacrificed at 14 months of age. The dams averaged 2.43 ± .20 abdominal fat percentage body weight with a coefficient of variation of 63%. The sires had no abdominal fat. The regression of abdominal fat percentage body weight of daughters at 8 weeks of age on percentage abdominal fat in dams at 14 months age was −.071 + .042 and for sons on dams was −.03 ± .035.