Comparison of the Growth Curve Models on Live Weights in Terms of Different Environmental Factors in Awassi Lambs

In this study, it was aimed to model the growth curves of Awassi lambs in terms of live weight-age relation-ships and macro environmental factors such as sex, birth type, year, month, and dam age, as well as to de-termine a nonlinear model that explains the growth curves better. For this purpose, Gompertz and Logistics were used. The data set of the study comprised of the 3523 Awassi lambs’ live weights obtained at 10, 20, 30, 50, 60, 90, and 120th days of age. In order to compare both models, the coefficient of adjusted determi-nation (R2adj) and the mean squared error (MSE) were used as the goodness of fit criteria. For the Gompertz and Logistics models, Gompertz model has the lowest MSE in all of macro environmental factors. While the estimated mean and standard errors of the asymptotic weight (A), the constant of integration (B), and growth rate (k) parameters were found respectively as 54.13 ± 0.59, 2.56 ± 0.008, and 0.01 ± 0.0001 for the Gompertz model, they were found respectively as 37.47 ± 0.18, 7.30 ± 0.03 and 0.03 ± 0.0001 for the Lo-gistic model. For the Gompertz and Logistic models, age at inflection point (AIP), weight at inflection point (WIP) and maximal increment (MI) were found to be 5.55, 19.92, 51.00 and 66.26, 18.74, 68.40, respec-tively. In addition, correlations between model parameters (rAB, rAk, rBk) were found as 0.86, -0.98, -0.75 and 0.45, -0.91, -0.08 respectively for the Gompertz and Logistics models.The model that better described the growth of Awassi lambs in terms of MSE, AIP, WIP, MI and rAB, rAk, rBk values were found as the Gompertz growth model.