Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 15, 2002
Publication Date: July 20, 2002
Citation: BRIDGES, T.C., BROWN BRANDL, T.M., TURNER, L.W., NIENABER, J.A. MODELING THE CHANGING GENETICS OF SWINE GROWTH. APPLIED ENGINEERING IN AGRICULTURE 18(4):497-502. 2002. Interpretive Summary: The genetic improvement in lean tissue growth of swine affects the accuracy of swine models. It is necessary to modify swine models such as NCPIG to make them representative and useful. This paper describes modifications to the NCPIG model and the results. Three example modifications are presented to show the importance of the type of data needed to make meaningful corrections. Accurate growth data alone are not enough to make good economic predictions.
Technical Abstract: The NCPIG swine simulation model was calibrated to model the growth of a more recent BT (Yorkshire, American Landrace cross) high lean growth genetic line developed at the Meat Animal Research Center (MARC) in Clay Center, Nebraska. Body weights measured in a growth experiment at MARC were used to calibrate the computer model. The simulated findings for the BT line were compared to the model results of the older BF genetic line (contemporary cross of Chester White, British Landrace, Yorkshire and British Large White) used to develop the model and those observed for both genetic types in the growth experiment. The BT genetic line grew faster, had larger daily gains and similar feed to gain ratios to the BF barrows. Three different simulated genotypes (BT1, BT2, BT3) were developed and compared to the observed animals. Each simulated BT genotype closely predicted the average body weights of the observed animals. But economic comparisons in a production situation showed vastly different results. Th production statistics of average feed intake, 10th rib back fat and the fat free lean index along with average body weight were used to determine that BT3 was the better choice in representing the observed animals.