Abstract: Heterogeneity of the residual variances was investigated for test day milk yields of Turkish Holsteins. A third order random regression model including the fixed, random additive genetic, permanent environmental and residual effects were used. Residual Variances (RV) of test day milk yields divided into different classes with 5 schemes as RV1, RV3, RV5, RV7 and RV10. Also, a structural model was fitted to residual variances of milk yields. The residual variances were estimated from 2.19-29.47 kg2 and additive genetic variances were estimated 3.19-10.97 kg2. The heritability estimates ranged from 0.12-0.81. The third order random regression models with RV7 and RV10 schemes were found to be better than others for evaluation of residual variances.
C. Takma and Y. Akbas , 2009. Heterogeneity of Residual Variances of Test Day Milk Yields Estimated by Random Regression Model in Turkish Holsteins. Journal of Animal and Veterinary Advances, 8: 782-787.