COMPARISON OF NON-LINEAR FUNCTIONS FOR DESCRIBING THE GROWTH OF DAIRY HEIFERS IN NORTHERN NEW SOUTH WALES

In 1993 a survey was undertaken on the North Coast of N.S.W. to determine the relationship between liveweight and age of 3,490 heifers from 25 to 962 days of age. Five non-linear functions were used to explain the relationship between liveweight (W) and age with a set of parameters that were biologically interpretable (Perotto et al. 1992). The data were fitted using TABLECURVE 3.0 cc) (Jandel Scientific 1992; see Table 1). The percentage deviations between average observed and predicted values from 25 to 962 days of age for each function are shown in Table 2.