Analysis of feed intake of individually fed beef bulls using random regression models

N. W. Selapa, K. A. Nephawe, A. Maiwashe, D. Norris, J. W. Ngambi

Research output: Contribution to journalArticle

Abstract

To estimate genetic parameters for weekly feed intake (FI) of beef bulls records of FI on Bonsmara bulls (n = 3 012) for 5 years were analyzed using random regression model (RRM). The model included the fixed linear regression of cumulative feed intake on third order orthogonal Legendre polynomials (OLP) of the actual days on test (d 7 to 84 weekly) for starting age group and contemporary group effects. Random regressions on third order OLP were included for additional random effect of weaning-herd-year (WHY) effect and additive genetic effect of the animal and on fourth order for the additional random permanent environmental effect of the animal. The residual effects were assumed to be independently distributed with heterogeneous variance for each measurement period. The first additive geneticeigen function (with 95.6% additive genetic variance contribution) revealed that selection for decreased cumulative FI at any test day would tend to decrease cumulative feed intake throughout the test and vice versa. Random regression model could be used in genetic evaluation of cumulative feed intakes of individually fed beef bulls in South Africa.

Original languageEnglish
Pages (from-to)223-226
Number of pages4
JournalJournal of Applied Animal Research
Volume36
Issue number2
DOIs
Publication statusPublished - Jan 1 2009

Fingerprint

beef bulls
feed intake
South Africa
Weaning
Linear Models
Age Groups
Bonsmara
group effect
testing
residual effects
genetic variance
Red Meat
bulls
animals
weaning
herds

All Science Journal Classification (ASJC) codes

  • Animal Science and Zoology
  • veterinary(all)

Cite this

Selapa, N. W. ; Nephawe, K. A. ; Maiwashe, A. ; Norris, D. ; Ngambi, J. W. / Analysis of feed intake of individually fed beef bulls using random regression models. In: Journal of Applied Animal Research. 2009 ; Vol. 36, No. 2. pp. 223-226.
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Analysis of feed intake of individually fed beef bulls using random regression models. / Selapa, N. W.; Nephawe, K. A.; Maiwashe, A.; Norris, D.; Ngambi, J. W.

In: Journal of Applied Animal Research, Vol. 36, No. 2, 01.01.2009, p. 223-226.

Research output: Contribution to journalArticle

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