Comparison of Non-Linear Models to Describe the Growth Curve of Moghani Sheep

قرباني, زينب and شيخلو, محمدرضا and صفري, رشيد and كريمي, امير Comparison of Non-Linear Models to Describe the Growth Curve of Moghani Sheep. In: 2nd International and 6th National Iranian Congress on Organic vs. Conventional Agriculture, August 2019, Ardabil, Iran.

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Abstract

In this research fitness of nonlinear models of Brody, Von Bertalanffy, Negative exponential, Logistic and Gompertz to describe the growth curve of Moghani sheep breed of Moghan station was studied. For this purpose, data on birth weight, three months, six months, nine months, and one year from 11913 Moghani sheep which were collected at Moghan Research Station located in Ardebil province, Iran, during 1987 to 2017 were used. Each model was fitted separately to body weight records using whole data the nonlinear least square (NLIN) procedure of SAS. The most suitable model was determined by R2 Root MSE, as well as Akaike information criterion (AIC). All used models in the current study fitted the growth data of Moghani sheep well based on different goodness of a fitting criteria. However, the results showed that Logistic growth model with the highest accuracy (R2=0.9768, AIC=31628.11) and the lowest error (MSE=25.41) could describe growth curve better than the other growth models, and was followed by Gompertz, Von Bertalanffy, Brody and Negative exponential growth models, respectively.

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