Metabolism and Nutrition VI: Feed Additives

cross was made between the 4 selected quail populations. Growth and yield was measured on 4 replicate pens for each cross, with each pen containing a minimum of 20 birds. Growth and yield for all crosses were evaluated at each of the 4 selection ages: days 10, 17, 28, and 40. Of particular interest in this study is the change in both reciprocal and heterotic effects over time. In this study it was observed that reciprocal and heterotic effects did change over time. In both cases nonadditive genetic variation seems to play a much greater role prior to rather than post point of inflection (POI). In general, the utilization of a line selected at or prior to POI is advantageous as it maximizes growth potential due to the effects of nonadditive variation. This advantage was apparent for both growth and yield parameters in this study. It is interesting to note that the crosses that resulted in the most heterosis were those that included a line selected at POI and a second line selected for late body weight.