J. Anim Sci.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J. Anim Sci. 1987. 65:1495-1499.
© 1987 American Society of Animal Science
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Aaron, D. K.
Right arrow Articles by Parish, N. R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Aaron, D. K.
Right arrow Articles by Parish, N. R.

Genetic Parameter Estimates for Preweaning Growth Traits in Santa Gertrudis Cattle1

D. K. Aaron2, F. A. Thrift2 and N. R. Parish3

University of Kentucky, Lexington 40546-0215 and King Ranch, Inc., Kingsville, TX 78363

Abstract

Genetic parameters were estimated for birth weight and weaning weight from records collected on 1,894 Santa Gertrudis calves (939 bulls, 955 heifers) during the 8-yr period, 1978 through 1985. Variance and covariance components were estimated separately by sex and combined across sexes utilizing mixed-model, least-squares procedures (Henderson's Method 3). The mathematical model assumed for estimating variance and covariance components by sex included effects of year, sire-within-year and age of dam. Also, calf weaning age was included as covariate for birth weight and weaning weight. Estimates were obtained across sexes utilizing the same model, with the addition of effects of sex of calf and the sex-of-calf x age-of-dam interaction. Heritabilities and genetic and phenotypic correlations were estimated using paternal half-sib techniques. The heritability estimate for birth weight for bulls was 1.6 times larger than that for heifers (.38 ± .12 vs .24 ± .10). Conversely, the heritability estimate for weaning weight for heifers was 1.5 times larger than that for bulls (.45 ± .12 vs .30 ± .11). However, based upon their approximate standard errors, neither of these differences was significant. Heritability estimates calculated across sexes were .32 ± .07 and .42 ± .08 for birth weight and weaning weight, respectively. Estimates of genetic and phenotypic correlations of birth weight and weaning weight by sex were .43 ± .21 and .31, respectively, for bulls and .33 ± .22 and .27, respectively, for heifers. Calculated across sexes, the genetic correlation was .40 ± .14 and the phenotypic correlation was .29.

Footnotes

1 Published with approval of Director of Kentucky Agric. Exp. Sta. as Journal Article 87-5-30.

2 Dept. of Anim. Sci., Univ. of Kentucky, Lexington.

3 King Ranch, Inc., Kingsville, TX.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1987 by the American Society of Animal Science.