Comparison of linear and non-linear models to predict the growth curve of dromedary camels

The present study aimed to determine the best mathematical model to describe the growth curve of dromedary camels. For this purpose, the data recorded between 1990 and 2018 in the National Research and Development Station on Dromedary Camel located in Bafgh, Yazd province, were used. The records included the body weight of 747 dromedary camels at different ages (from birth to 14 months of age). To determine the best model describing the growth curve of dromedary camels, eight different mathematical models including linear, quadratic, cubic, Gompertz, Brody, logistic, monomolecular, and von Bertalanfy were compared. The age of camels was included in the model as an independent variable and the weight of camels as a dependent variable. The criteria for comparing the performance of the models were having the highest value of the corrected coefficient of determination (R2 adj) or the lowest values of Akaike information criterion (AIC) and the mean square error (MSE). Based on the results of this study, the accuracy of linear, quadratic, and cubic equations in describing the growth curve of dromedary camels was significantly lower than that of Gompertz, logistic, monomolecular, von Bertalanfy and Brody models. The results of the present study showed that the weight of dromedary camels could be predicted precisely up to weaning age (200 days), However, after weaning, due to the effect of different environmental conditions on the growth of camels and a sudden change in feed type, the increase in camel weight does not have a linear relationship with their age, and it is better to use other parameters such as biometric measurements to accurately estimate camel weight.