Comparison of growth curves of weight selected populations of turkeys, quail, and chickens

The pattern of growth from hatch to sexual maturity was measured in quail, chicken, and turkey females using the Gompertz equation. Quails and chickens were selected for high or low immature BW and turkeys were selected for high BW. Quail and turkey species also included their respective randombred control populations. The chicken species included an F2 of the selected lines. Thus, there were considerable differences in BW not only among species but between lines within species. Differences were evident at hatch as hatch weights relative to asymptotic BW were greater for quail than chickens and turkeys. Age and BW traits associated with point of inflection (POI) were variable. Species differences appeared to be influenced by the selection scheme applied to the populations. Slope at POI was greatest in quail and the same for turkeys and chickens. Age at 90% of the asymptotic BW was generally greatest for chickens, intermediate for turkeys and lowest for quails. Selection age in relation to age at POI may contribute to the timing and magnitude of growth response observed.