COMPARISON OF THE EFFECTIVENESS OF MULTIPLICATIVE AND ADDITIVE ADJUSTMENT FACTORS IN PREWEANING AVERAGE DAILY GAIN OF BEEF CATTLE

Abstract

Sixteen adjustment procedures were used to correct 16,529 Angus and, 47,293 Hereford preweaning average daily gain records from the l97l-1972 Canadian Federal-Provincial R.ecord of Performance (ROP) Program. Two criteria were defined to determine the appropriateness of additive- or multiplicative-type adjustments and to determine the best of 16 adjustment procedures. Included in the comparisons were the currently used multiplicative ROP age-of-dam factors. Tests for interactions of time with age-of-dam by sex-of-calf by environment subclasses indicated a preference for additive type factors. The best adjustment procedure of those compared for removing age-of-dam effects and interactions of age of dam with sex and environment was the additive simultaneous adjustment for age of dam, sex of calf, and feeding system. Both the scientific and practical implications of this study were considered important.