Comparison of Growth of Male and Female Kids of Nondescript Goats in a Semi Arid Region of Nigeria

This study compared the use of five different models to describe the growth from birth to 20 weeks of age of kids from both genders of nondescript goats. Fifty nine (59) nondescript kids were weighed weekly at the university of Maiduguri livestock teaching and research farm, Nigeria and the live weights were modeled. Biologically relevant variables were estimated for each kid from the Logistic, Gompertz, Richards, Monomolecular and Weibull models. Models were compared using the following goodness of fit criteria: coefficient of determination (R2), mean square error (MSE), standard deviation (SD) and Akaike information criteria (AIC). In both genders, all nonlinear models fitted the data well, with high R2 ranging from 0.911 to 0.943 and 0.923 to 0.95 for male and female, respectively. In addition, the males had higher asymptotic weight than females while the reverse was observed with regards to maturing rate. Male kids had heavier inflexion weight and higher age than females for all the models. These values were however higher for Logistic than Gompertz model. The monomolecular model had higher R2 and lower MSE, SD and AIC in both male and female kids. It can be concluded that the nonlinear growth models were suitable for estimating live weight as a function of age for both male and female of nondescript kids in Nigeria. However, the best model was the monomolecular based on model parameters and goodness of fit criteria.