Current measures of growth patterns are not uniformly applicable to the variety of growth curves for individual goat. Moreover they are either difficult to interpret or are functions of whole growth and therefore inappropriate. In this study, six, robust parametric measure is derived from a perfect fit of fifth order polynomial function of the growth data from birth to 6 months. The curvilinear model (parabolic equation) is appropriate for trend analysis, a major manifestation of which is growth rate, the decrease rate in growth rate and the initial body weight. Data fitted to the model were obtained from a total of 338 pure Aradi, pure Damascus and crossbred kids from of 141 does and 21 sires. The results show that the six order polynomial function for growth has a little more advantage (was no significant) in accuracy but, its more complicated to calculate the parameters than the other one which have three parameters of them with no biological meaning. Therefore, the fitting of quadratic curve to growth pattern of goat data resulted in a simple, precise and robust parametric measure with biological interpretation. The largest growth rate was found in kids born in season 3. The largest (f) initial body weight (birth weight) was found in crossbred kids. The smallest daily decrease in growth rate was found in group 1 following by group 3crossbred (½ pure Aradi + ½ Damascus). |
