A comparison of statistical techniques for analysis of growth curves

Frequently, experiments are conducted in order to investigate the effects of various treatments on an animal's growth rate. The data from these investigations usually consist of each animal's body weight or accumulative weight gain at specific times during the experiment. The most common statistical techniques for analysis of growth rates (increments in body weight over time) consider only terminal body weights or final accumulative weight gain. In this study, we compare growth rates over the duration of the experiment and use standard simultaneous testing procedures in order to accommodate more than two treatment groups. Results obtained by comparison of regression lines randomization analysis of variance, and repeated measures analysis are presented.