Dietary total sulfur amino acid requirement for optimal growth performance and carcass characteristics in finishing gilts

Finishing gilts (initially 163 lb) were fed .58% total lysine (.50% apparent digestible) and total sulfur amino acid (TSAA) concentrations of .26,.285, .31, .335, and .36% (.225 to .325% apparent digestible). These values represent TSAA: lysine ratios of 45, 50, 55, 60, and 65%. Results suggest a linear decrease in ADG and ADFI along with poorer F/G with increasing TSAA levels. However, gilts fed .285% TSAA (50% of lysine) had the best ADG and F/G. No effect was observed on any carcass criteria. Based on the results of this study, the TSAA requirement is not greater than .285% total (.25% apparent digestible) or approximately 50% of the lysine requirement.