Please use this identifier to cite or link to this item:
https://hdl.handle.net/1959.11/705
Title: | A Comparison of Methods to Pre-adjust Data for Systematic Environmental Effects in Genetic Evaluation of Sheep | Contributor(s): | Brown, D (author); Reverter, A (author) | Publication Date: | 2002 | Open Access: | Yes | DOI: | 10.1016/S0301-6226(01)00326-8 | Handle Link: | https://hdl.handle.net/1959.11/705 | Abstract: | Sheep performance data are routinely adjusted to account for systematic environmental effects but little attention has been given to the choice between the methods available. This study compares methods to adjust liveweight measurements for individual age (within group regression vs. age intercept) and age of dam (dam age class vs. quadratic polynomial on dam age) and fat and eye muscle depth for liveweight (within group regression vs. quadratic polynomial on weight). Criteria for comparison included: (1) changes in phenotypic variance and heritability estimates; (2) predictive ability of resulting estimated breeding values (EBVs); (3) correlation between adjusted and adjustor variables; and (4) ease of computation. With the exception of dam age adjustment of liveweight, adjustment methods did not influence the phenotypic variance of the trait being adjusted. Increases in the direct heritability were observed for liveweight adjusted using the age intercept, dam age class and quadratic methods, and fat depth using quadratic adjustment for liveweight. Within group regression based adjustments generally resulted in a reduction of direct heritability. Maternal heritability and permanent environment due to dam were unaffected by the adjustment methods utilised. The regression of progeny performance on sire estimated breeding value also indicated that the age intercept produced estimated breeding values that were closer to the expectation than those using the within group regression adjustment. The age intercept and quadratic polynomial methods of adjustment appear to be slightly more appropriate for genetic evaluation purposes. | Publication Type: | Journal Article | Source of Publication: | Livestock Production Science, 75(3), p. 281-291 | Publisher: | Elsevier BV | Place of Publication: | Netherlands | ISSN: | 1872-6070 0301-6226 1871-1413 |
Fields of Research (FoR) 2008: | 070201 Animal Breeding | Peer Reviewed: | Yes | HERDC Category Description: | C1 Refereed Article in a Scholarly Journal |
---|---|
Appears in Collections: | Animal Genetics and Breeding Unit (AGBU) Journal Article |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
open/SOURCE01.pdf | Author final version | 120.93 kB | Adobe PDF Download Adobe | View/Open |
SCOPUSTM
Citations
2
checked on Sep 14, 2024
Page view(s)
1,338
checked on May 26, 2024
Download(s)
336
checked on May 26, 2024
Items in Research UNE are protected by copyright, with all rights reserved, unless otherwise indicated.