The growth curve parameters of Japanese quail (Coturnix coturnix japonica) help in developing breeding strategies by modifying the management practices and can be useful in pre-selection of the birds as it provides prediction of future growth at any age. The study was conducted on fortnightly body weights of 681 black and 565 white plumage Japanese Quails. Four growth curve models viz. Gompertz, Von Bertalanffy, Richard’s and Logistic functions were fitted to the body weights for estimation of the curve parameters and identification of the best function based on root mean squares error (RMSE) values. The parameter estimates viz. asymptotic (mature) weight, scaling parameter, maturing rate and shape parameter were ranging from 189.34-217.20, 0.92-15.86, 0.35-0.68 and 0.55-0.73, respectively. The RMSE values were 3.12, 4.50, 1.77 and 2.21 g for overall data; 3.48, 4.62, 2.14 and 2.28 g for male quails; 3.58, 5.00, 2.48 and 2.97 g for female ones; 3.83, 4.88, 3.03 and 3.27 g for black quails; and 3.08, 4.63, 2.65 and 1.87 g for white quails; respectively using these functions. Richards function was the best fit for overall, male, female and black categories of observations whereas Logistic function had the better fit for white quails than Richards function.

Highlights

• Four growth curve functions were fitted to the fortnightly body weights in black and white strains of Japanese quails.
• Richards function had the best fit for different classifications followed by Logistic function based on RMSE values.