Akademik Veri Yönetim Sistemi
II. INTERNATIONAL LIVESTOCK STUDIES CONGRESS, Antalya, Türkiye, 29 - 30 Ekim 2021, ss.15, (Özet Bildiri)
The Effect of Gender, Birth Type and Age of Dam on Growth Curve Parameters in Hair Goats
Abstract
Growth curve parameters, age and weight at point of inflection (IPT and IPW) can be used for selection of livestock animals. In this study, monthly 3858 test day body weight records of 643 hair goat kids up to 150 days of age were used to fit growth curve and estimate growth curve parameters using with Gompertz and Von Bertalanffy models which are the most used non-linear functions. The live weights of kids were divided into three group; age of dam (3, 4, 5, 6, 7 years), sex (female, male) and birth type (single, twin). With respect to goodness of fit, although both models had high R2, Gompertz model was determined the best fit for all factors with higher values of determination coefficient (R2) and adjusted determination coefficient (R2adj) and lower values for Akaike information criteria (AIC), Bayesian information criteria (BIC) and mean square error (MSE). Effect of sex, age of dam and birth type on IPT, IPW and growth curve parameters (A, B and K) were analyzed with General Linear Model (GLM) in SPSS Version 22.0. Sex of kids showed significant differences for parameter K (p<0.001), IPW and parameter A (p<0.01) while birth type showed significant differences for B and K parameters (P<0.001). As for age of dam, no significant differences were found on any of parameters. In conclusion, Gompertz and Von Bertalanffy models can be used for selecting hair goat kids by prediction of their growth curve traits which would provide more efficient breeding strategies in goat farming. With obtained remarkable results, growth curve parameters should be planned considering birth type and sex effects in the selection strategies of hair goat kids.
Keywords: Growth, growth curve, hair goat, non-linear regression, parameter estimation