GRAZPLAN: Decision support systems for Australian grazing enterprises .2. The animal biology model for feed intake, production and reproduction and the GrazFeed DSS

This paper specifies the animal biology module of a model for simulating grazing systems for ruminants on pasture. The program predicts the intake of energy and protein, allowing for selective grazing and substitution by supplementary feeds, and estimates the use of the diet for maintenance and production, according to current feeding standards. Conception and death rates are predicted from the maturity and condition of the animals. The model is designed to be of general application to any type of sheep or cattle on any pasture. GrazFeed is a discrete package that uses the same procedures for predicting feed intake and productivity within a tactical decision support system. This is designed to help graziers to assess the feeding value of specified pastures and the need for the supplementary feeding of different classes of grazing animals. (C) 1997 Published by Elsevier Science Ltd.