NUTRIENT REQUIREMENTS FOR CANADIAN YORKSHIRE SWINE: V. A STUDY OF THE LYSINE AND PROTEIN REQUIREMENTS OF FINISHING PIGS WEIGHING FROM 100 TO 200 LB

Abstract

Ninety-six pigs (48 barrows, 48 gilts) were allotted according to sex and previous ration to three linear-programmed finisher rations: (1) 13% protein and 0.55% lysine, (2) 13% protein and 0.67% lysine, and (3) 16% protein and 0.67% lysine. Growth rates, digestibility coefficients for energy and protein, feed consumption, and carcass data were obtained.In terms of growth rates and efficiency of energy utilization 16% protein rations were superior to 13%, but increasing lysine from 0.55 to 0.67% with 13% protein rations was as effective as increasing the protein level. However when cross-sectional area of longissimus dorsi muscle and back fat deposition were considered, increasing the protein level was more effective than extra lysine in promoting a high lean:fat ratio.Evidence of an inverse relationship was observed between rate of gain during the growing period and rate of gain during the finishing period, particularly in barrows.