LONG-TERM ANIMAL RESEARCH IN GENETIC-IMPROVEMENT OF LIVESTOCK AND POULTRY

In animal experimentation, long-term studies have contributed substant ially to our knowledge of genetics in particular, and of nutrition, ph ysiology, and reproduction, to lesser extents. Long-term genetic selec tion experiments have yielded information on selection limits, dissipa tion of genetic variance over time, and created unique lines which may be utilized as consumer demands shift. Costs of long-term experimenta tion are not inordinately high in comparison to other experimentation, if economic animal species are used and returns from animal products are recovered to help finance the experiment. Government finance is, h owever, required for long-term experimentation, as private industry ha s little motivation for this work. The paper outlines recent significa nt contributions of long-term experimentation, and provides guidelines for planning experiments.