Relative Efficiency of Selection Methods for Improvement of Feed Efficiency

A set of optimum weighting factors was derived such that the resulting linear index may be used to select for the ratio of two component traits. In a population of mice, three selection criteria for improvement of feed efficiency (body weight gain/feed intake) were compared: 1) selection on a linear approximation of the efficiency ratio, 2) selection on body weight gain, and 3) restricted selection index for increased body weight gain with feed intake constant. Direct selection on a lifiear approximation of the efficiency ratio was 10% and 3% more effective than selection on body weight gain and restricted selection index. Selection on linear approximation was preferred over restricted index selection in improving efficiency of feed utilization in laboratory and farm animals.