COMPARISON OF GOMPERTZ, LOGISTIC AND RICHARDS GROWTH MODELS FOR DESCRIBING GROWTH CURVES OF DOMESTIC PIGEON SQUABS (COLUMBA LIVIA) IN MAIDUGURI, BORNO STATE, NIGERIA.

Abstract

This research was carried out to describe the growth patterns of male and female domestic pigeon squabs and determine the most suitable model. Body Weight data from hatch to 30 days of age and 3 nonlinear mathematical functions (Richards, Gompertz, and Logistic) were used to estimate growth patterns of the pigeon squabs. In general, male squabs are significantly (P<0.05) heavier than females at all ages, an indication that there is sexual dimorphism in pigeons at the early ages. The Gompertz recorded highest asymptotic weights (317.25 and 314.87 g) for both male and female squabs while the Richard had the least (311.10 and 303.63 g). However, the asymptotic weights estimated by both Logistics and Richards models were very close for both males (312.89 and 311.10 g) and females (305.45 and 303.63 g). This might imply that both models will have almost the same level of accuracy in predicting the weight of squabs. Comparing the models by Akaike’s Information Criterion (AIC) values and Mean Square Error (MSE) showed that all the models have similar values with Gompertz (9007.4 and 8122.4) had the highest values for males compared to the Richards (9005.5 and 8098.4) and Logistic (9003.6 and 8091.8) models. A similar trend was observed for females. Though, the R2 values (>0.80) showed that Richards model adequately described the growth of pigeon squabs, the results confirmed that the Richards model was more suitable, followed by the Logistic and Gompertz models based on AIC and MSE.