SHEEPO VERSION-4.0 - A SHEEP MANAGEMENT PACKAGE

This paper demonstrates the verification and validation of the mathema tical relationships for a summer rainfall version of SheepO (version 4 .0), a Decision Support System that simulates pasture and sheep produc tion. SheepO (version 3.0) was primarily developed for the winter rain fall areas of Southern Australia and over predicted the available past ure in a summer rainfall environment. These differences have led to th e implementation and development of three regional models: water balan ce, digestibility and shoot death. The development phase used producti on data for fine wool Merino wethers (4-5 years old) grazing on a Phal aris/White clover pasture (Armidale, Lat. 30 degrees, 31'S, Alt. 1070 m). The verification of version 4.0 shows the calibration of pasture a nd sheep production at a low (9.9 sheep/ha) stocking rate and the expe rimentation of making one management change to a high stocking rate (1 9.8 sheep/ha). Similarly, validation is shown using an independent dat a set (Glen Innes, Lat. 29 degrees, 42'S, Alt. 1057 m) of fine wool Me rino wethers (8 months old) at low and high stocking rates, respective ly 10 and 15 sheep/ha. SheepO version 4.0 will now assist advisers, pr oducers and researchers in a summer rainfall environment to investigat e the outcome of changes to current management strategies. Copyright ( C) 1996 Elsevier Science Ltd.