INTERNAL VALIDATION OF A COMPUTERIZED SYSTEMS-MODEL FOR HEALTH MANAGEMENT DECISION-SUPPORT IN GROWING HOGS

A study was designed to conduct an internal validation of a computeriz ed systems model for health management decision support in growing hog s. Evaluation focused on both the alpha-beta tracker, which was employ ed to predict underlying system variables, and the simulation model it self, which predicted system performance. Both mean absolute predictio n error and Theil's u(2) statistic were calculated Simulation scenario s were designed to highlight specific aspects of the model. In additio n, a case example was developed to demonstrate the model's logical con sistency and its applicability for assessing the economics of health m anagement decisions. Use of the alpha-beta tracker to project data ser ies, including pig deaths and disease prevalence rates at slaughter, w as largely unsuccessful. The model consistently predicted hogs markete d such that 0 < u(2) < 1. Also, decreased disease rates improved both physical and financial performance as expected. Depending on the quart er involved, the maximum bid to achieve a 50% decrease in the prevalen ce rates of pneumonia at slaughter and a 10% decrease in the prevalenc e rates of atrophic rhinitis at slaughter ranged from $0.15 to $0.37 p er hog marketed for one producer. Future validation efforts should emp hasize data quality and the effects of disease on production while see king system application in a commercial production setting.