|
|
||||||||
1 DLO-Institute for Animal Science and Health, Box 65, 8200 AB Lelystad, The Netherlands
2 Dutch Cattle Syndicate, Box 454, 6800 AL Arnhem, The Netherlands
3 DLO-Agricultural Mathematics Group, Box 100, 6700 AC Wageningen, The Netherlands
A method is presented to estimate breeding values that corrects for phenotypic heterogeneous variances within herd-year. Heritabilities are assumed to be homogeneous. A multiplicative mixed model is used that simultaneously estimates breeding values and heterogeneity factors. Information on the other herd-years within a herd is used to improve the accuracy of the estimation of variances within herd-year by applying an autoregressive model to the herd-year variances. Estimates for the phenotypic heterogeneous variances account for differences among breed and genetic groups, relationships between animals, and reductions in variance from selection. This type of estimate avoids selection that favors animals from inferior breeds and genetic groups, from herds with closely related animals, and from later parities. The method is computationally feasible for the large data files used in the dairy industry. Computation time is about twice that needed without correction for heterogeneity.
When applied to the Dutch national dairy data, the mean difference between the parent average and the EBV of progeny-tested bulls was reduced by 38% when heterogeneous variances were considered. Also, the variance of EBV minus parent average was reduced by 18%. The coefficient of variation of the heterogeneous variances was approximately 0.32. Variances hardly differed over the years within a herd (i.e., were homogeneous within herds). The latter suggests a simplified model with variances estimated within herds.
Key Words: heterogeneous variances mixed linear models breeding value estimation
Submitted on July 27, 1995
Accepted on October 26, 1995
This article has been cited by other articles:
![]() |
H. Nakaoka, A. Narita, T. Ibi, Y. Sasae, T. Miyake, T. Yamada, and Y. Sasaki Effectiveness of adjusting for heterogeneity of variance in genetic evaluation of Japanese Black cattle J Anim Sci, October 1, 2007; 85(10): 2429 - 2436. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Gengler, G. R. Wiggans, L. L. M. Thornton, J. R. Wright, and T. Druet Accounting for heterogeneous variances in multitrait evaluation of Jersey type traits. J Dairy Sci, August 1, 2006; 89(8): 3143 - 3151. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. J. Windig, M. P. L. Calus, B. Beerda, and R. F. Veerkamp Genetic Correlations Between Milk Production and Health and Fertility Depending on Herd Environment J Dairy Sci, May 1, 2006; 89(5): 1765 - 1775. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. L. Powell and H. D. Norman Major advances in genetic evaluation techniques. J Dairy Sci, April 1, 2006; 89(4): 1337 - 1348. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Gengler, G. R. Wiggans, and A. Gillon Adjustment for Heterogeneous Covariance due to Herd Milk Yield by Transformation of Test-Day Random Regressions J Dairy Sci, August 1, 2005; 88(8): 2981 - 2990. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Mark Applied Genetic Evaluations for Production and Functional Traits in Dairy Cattle J Dairy Sci, August 1, 2004; 87(8): 2641 - 2652. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. F. Fikse Comparison of Performance Records and National Breeding Values as Input into International Genetic Evaluation J Dairy Sci, August 1, 2004; 87(8): 2709 - 2719. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Gengler, G. R. Wiggans, and A. Gillon Estimated Heterogeneity of Phenotypic Variance of Test-Day Yield with a Structural Variance Model J Dairy Sci, June 1, 2004; 87(6): 1908 - 1916. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. P. L. Calus and R. F. Veerkamp Estimation of Environmental Sensitivity of Genetic Merit for Milk Production Traits Using a Random Regression Model J Dairy Sci, November 1, 2003; 86(11): 3756 - 3764. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. P. L. Calus, A. F. Groen, and G. de Jong Genotype x Environment Interaction for Protein Yield in Dutch Dairy Cattle as Quantified by Different Models J Dairy Sci, November 1, 2002; 85(11): 3115 - 3123. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |