Abstract
This paper is an analytical survey of the factors to be considered in designing dairy feeding experiments. The problems of choosing experimental subjects, treatments, and response measures, the desirability of estimating experimental errors and the concepts of experimental sensitivity and experimental efficiency are discussed in a general way. Matters of error control and experimental design are discussed in detail, with special reference to dairy experiments. To point up the logical basis of error control, attention is focused on the lactation curve and factors affecting its general trend and shape. Designs for continuous and change-over trials are discussed in terms of controlling the factors affecting the lactation curve. Carry-over effects in change-over trials and ways proposed to surmount them are considered. Some comments to guide researchers in choosing between continuous trials and between different types of change-over designs are made.