Determining the Optimal Threonine:Lysine Ratio for the 25 to 50 LB Pig

Kansas State University Swine Research. A 21-day growth trial was conducted to determine the threonine:l ysine ratio necessary to optimize growth per formance of the 25 to 50 lb pig reared in a high-health, segregated earlyweaning (SEW) system. T en experimental diets, including two levels of lysine (.75% and 1.10% apparent digestible lysine) and five apparent digestible threonine:lysine ratios (40, 47.5, 55, 62.5, and 70%), were used in a 2 5 factorial arrangement. Growth performance was improved by feeding 1.10% rather than .75% digestible lysine. Also, results indicated that the apparent digestible threonine requirement for the SEW-reared, 25 to 50 lb pig is approximately 55% of digestible lysine.