Growth, food conversion, carcass yields and their heritabilities in ducks (anas platyrhynchos)

1. Live weight, food consumption, eviscerated carcass weight, breast muscle mass and ratios of these traits were measured in a strain of ducks of known pedigree. Heritabilities, genetic and phenotypic correlations were estimated for all traits. From the results the following conclusions are drawn.

2. Selection for live weight at market age would be simplest and most effective in improving growth rate and food conversion efficiency though would not necessarily markedly improve carcass lean meat.

3. Selection to increase the proportion of breast muscle (heritability (h ² ): 0.55) should be effective but might depress body weight as a correlated response. The effect on fat content is uncertain.

4. Selection for food conversion efficiency (h² : 0.21) might be expected to increase body weight, but its effect on carcass lean meat (proportion of breast muscle) is uncertain.

5. Selection for breast muscle mass (h ² : 0.41) should improve body weight and food conversion efficiency but its effect on proportion of lean meat is much less certain (rG = 0.45 + 0.17).