Development of a model to describe the compositional growth and dietary lysine requirements of pigs fed ractopamine.

摘要: The objective of this research was to use recent ractopamine data develop an updated mathematical model describe the daily compositional growth pigs fed ractopamine. Mean increases 18.2, 23.1, and 25.0% for protein accretion were assumed 5, 10, 20 ppm overall gain 40 kg BW during feeding period. relative effect described rapid increase subsequent decrease in as a function or days on test concentration (RC, ppm). reduction ME intake produced by 0.036 x (RC/20) 0.7 multiplied first gain, then increasing 0.078 at ratio fat-free muscle increased 14 16% with ractopamine, depending dietary lysine/essential AA levels. carcass fat empty body lipid when lysine essential requirements met. Daily lean functions intakes. percentage from 6.80 7.15%, concentration. Equations predicting measurements, such longissimus depths weight composition, modified incorporate prediction biases For four concentrations (0, ppm, respectively) 78 110 period, predicted performance levels ADG (1.03, 1.15, 1.16, 1.16 kg/d), gain:feed (kg ADG/kg ADFI; 0.360, 0.401, 0.412, 0.425), dressing (75.1, 76.0, 76.3, 76.4), (48.7, 51.0, 51.5, 52.2), area (38.8, 41.8, 42.5, 43.5 cm 2 ), 10th-rib depth (22.1, 19.8, 19.3, 18.7 mm), (321, 446, 467, 495 g/d), comparable data. allows be added farm specific pig curves. It can used evaluate ways optimize including duration feeding,