Length of Test for Sulfur Amino Acid Studies with Laying Hens

PAST experiments conducted to determine the protein or amino acid requirement of laying hens have ranged from three to twelve months in length. The long test period has been considered to be desirable in order to accurately evaluate the protein requirement. The purpose of the study presented herein was to determine the optimum length of an experiment for assessing the sulfur amino acid requirement of laying hens. EXPERIMENTAL PROCEDURE Monthly egg production data from two experiments and egg weight data from one experiment were analyzed. Each experiment was conducted over ten 28-day periods, with data being analyzed at the end of each month. In these analyses the data from the first month was omitted since it was felt that this period was necessary for the hens to adjust to the experimental diets. The data reported by Harms and Damron (1969) concerning the evaluation of the methionine requirement of the laying…