Longitudinal analysis of body weight and average daily feed intake during the feedlot test period in Angus cattle

Author(s)
Torres-Vazquez, Jose Antonio
Duijvesteijn, Naomi
van der Werf, Julius H J
Clark, Samuel A
Publication Date
2020-05
Abstract
The objectives of this study were to compare different models for analysing body weight (BW) and average daily feed intake (ADFI) data collected during a 70‐day feedlot test period and to explore whether genetic parameters change over time to evaluate the implications of selection response. (Co)variance components were estimated using repeatability and random regression models in 2,071 Angus steers. Models included fixed effects of contemporary group, defined as herd-year-observation_date-age, with additive genetic and permanent environmental components as random effects. Models were assessed based on the log likelihood, Akaike's information criterion and the Bayesian information criterion. For both traits, random regression models (RRMs) presented a better fit, indicating that genetic parameters change over the test period. Using a two-trait RRM, the heritability from day 1 up to day 70 for BW increased from 0.40 to 0.50, while for ADFI, it decreased from 0.44 to 0.33. The genetic correlation increased from 0.53 at day 1 up to 0.79 at day 70. Selection based on an index assuming no change in genetic parameters would yield a 2.78%-3.13% lower selection response compared to an index using parameters estimated with RRMs and assuming these genetic parameters are correct. Results imply that it may be beneficial to implement RRMs to account for the change of parameters across the feedlot period in feed efficiency traits.
Citation
Journal of Animal Breeding and Genetics, 137(3), p. 281-291
ISSN
1439-0388
0931-2668
Pubmed ID
31535413
Link
Publisher
Wiley-Blackwell Verlag GmbH
Title
Longitudinal analysis of body weight and average daily feed intake during the feedlot test period in Angus cattle
Type of document
Journal Article
Entity Type
Publication

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