Evaluation of an Updated Model to Describe the Compositional Growth of Pigs Fed Paylean

Pork producers have the goal to efficiently produce lean, quality pork to compete with alternative animal products. The implementation of lean value carcass pricing systems has led to the selection of pigs with increased lean growth rates, increased carcass lean percentages, and improved lean feed conversion. Health, nutrition, and facility management strategies have been implemented to increase commercially achievable lean growth rates. Paylean (ractopamine hydrochloride by Elanco) is a feed additive that has the potential to further increase the rate and efficiency of muscle tissue growth. Paylean has been approved to be fed at levels of 4.5 to 18 grams per ton (5-20 ppm) from 150 to 240 lbs live weight (last 90 lbs of live weight gain prior to market). Numerous Paylean research trials were conducted for 1987 to 1991. Because genetic selection has changed the pigs, the response to Paylean may have changed. The objective of this research was to utilize new Paylean research data and develop an updated daily growth model to describe the daily compositional growth of pigs fed alternative levels of Paylean. Future research can utilize this model to evaluate alternative nutrition, management, and marketing strategies.