author(s)
Ravindra G Nimase, Yogesh B Kandalkar and Yogesh C Bangar

abstract
The aim of the present study was to determine the most suitable model among six non-linear growth models viz., Brody, Von Bertalanffy, Richards, Logistic, Gompertz and negative exponential, used for describing the growth curve of 215 Magdyal male and female lambs maintained at Department of Animal Husbandry and Dairy Science, Mahatma Phule Krishi Vidyapeeth (MPKV), Rahuri (India) from 2006 to 2014. Non-linear modeling was done by using monthly body weights from birth to 12 months of age in male and female lambs separately. Among the models used, Brody model and Richards model showed close fitting for growth curve with high values of adjusted R² value (> 99%) and least values of root means square error (RMSE), Akaike’s information criterion (AIC) and Bayesian information criterion (BIC). However, due to simple interpretation and high precision, Brody model was considered as most suitable model for growth curve characteristics of Madgyal sheep. The parameter estimates for asymptote weight (A), initial constant to asymptote weight (B) and maturation rate (k) under Brody model for male lambs were 28.35±0.86, 0.85±0.02 and 0.19±0.02, respectively, in case of female lambs, it were 25.23±0.20, 0.85±0.01 and 0.21±0.01, respectively.