Description of lamb growth using random regression on field data

Title
Description of lamb growth using random regression on field data
Publication Date
2004
Author(s)
Fischer, Troy
Van Der Werf, Julius Herman
( author )
OrcID: https://orcid.org/0000-0003-2512-1696
Email: jvanderw@une.edu.au
UNE Id une-id:jvanderw
Banks, Robert
Ball, Alex
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Elsevier BV
Place of publication
Netherlands
DOI
10.1016/j.livprodsci.2004.02.004
UNE publication id
une:2940
Abstract
Random regression has been proposed as an accurate method for evaluation of growth data; however, this method has seldom been applied to data from an extensive industry where few records per animal exist. Consequently, field data containing weights of Poll Dorset sheep from 50 to 500 days of age were analysed fitting a random regression model. This model included quadratic, orthogonal polynomials for direct genetic and environmental effects and maternal environmental effects, a linear polynomial for maternal genetic effects and heterogeneous error variances. Direct heritability estimates increased steadily throughout time and were in agreement with literature estimates taken at specific ages. Some estimates for the highest ages with the least records tended to be overestimated, in particular heritability beyond 450 days. Research to solve this problem may require use of a function other than a polynomial. Variances due to maternal genetic effects were low throughout the trajectory. Covariances between weights of sheep for a considerable range of ages can be modelled adequately using random regression.
Link
Citation
Livestock Production Science, 89(2-3), p. 175-185
ISSN
1872-6070
0301-6226
1871-1413
Start page
175
End page
185

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