•  
  •  
 

Turkish Journal of Veterinary & Animal Sciences

Growth Curve in Akkaraman, Ivesi x Akkaraman and Malya x Akkaraman Lambs

DOI

-

Abstract

Weekly body weights from approximately 10 weeks of age to 19-29 weeks of age were used to study growth curve in Akkaraman, Ivesi x Akkaraman and Malya x Akkaraman lambs. A linear model was fitted to means of body weights using age as independent variable. The linear model provided a good fit with R2 values of 99%, 99.3% and 98.9% for Akkaraman, Ivesi x Akkaraman and Malya x Akkaraman, respectively. Afterthat, a common regression coefficient was calculated as within lambs regression coefficient, which gave R2 values of 95.9%, 97% and 95.8% for Akkaraman, Ivesi x Akkaraman and Malya x Akkaraman lambs, repectively. However, test of homogeneity of regression coffecient verified that there was an evidence of a statistically significant diversity of regression coefficients fitted to each lamb, which means that the growth pattern of all lambs cannot be represented by a common regression equation. Moreover, the data were analyzed considering several measurement on body-weight at each time point. In this way, residual sum of squares was divided into two parts: pure error from repeated measurements and lack of fit sum of squares. This method led to a decline in R2 values, which were 79.1%, 91.7% and 88.4% for Akkaraman, Ivesi x Akkaraman and Malya x Akkaraman lambs, respectively.

Keywords

Linear model, common regression, homogeneity of regression, pure error, lack of fit, lambs

First Page

267

Last Page

275

This document is currently not available here.

Share

COinS