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


     

J. Anim Sci. 1985. 60:1142-1155.
© 1985 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 Irgang, R.
Right arrow Articles by Robison, O. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Irgang, R.
Right arrow Articles by Robison, O. W.

Selection for Weaning Weight and Postweaning Gain in Hereford Cattle. II. Response to Selection1

R. Irgang2, E. U. Dillard3, M. W. Tess3 and O. W. Robison3

North Carolina State University,3, Raleigh 27695-7621

Abstract

Single trait selection was practiced in three lines of Hereford cattle at two locations. Bulls were selected within sire families for increased weaning weight (WW) in the WW line (WWL), for postweaning gain (PG) in the PG line (PGL) and at random in the control line (CTL). Data include the performance of 2,467 calves produced from 1967 to 1981. Environmental effects were estimated from CTL (method I) and from multiple regression procedures (method II). Phenotypic and environmental time trends were negative for WW and generally were positive for PG. Estimated genetic gains for WW in WWL were 1.07 ± .51 kg/yr in bulls and .62 ± .36 kg/yr in heifers using method I and .50 ± .31 kg/yr in bulls and .10 ± .17 kg/yr in heifers using method II. Corresponding values for PG in PGL were .85 ± .40 and 1.03 ± .24 kg/yr in bulls and .30 ± .28 and .37 ± .12 kg in heifers. Correlated genetic gains for WW in PGL were larger than direct WW gains, whereas genetic gains for PG in WWL were smaller than direct PG gains. From method I, estimates of realized heritability
Figure 1
for WW were .31 ± .18 in bulls and .22 ± .13 in heifers. For PG,
Figure 2
was .31 ± .13 in bulls and .06 ± .12 in heifers. Using method II,
Figure 3
for WW was .09 ± .08 in bulls and .02 ± .07 in heifers. Corresponding values for PG were .29 ± .10 and .11 ± .08. Joint estimates of the realized genetic correlation between WW and PG were .69 ± .18 and .46 ± .31 for methods I and II, respectively. Variation in selection response was evaluated using quasi-replicates. Results of this study indicate that selection for PG improved both WW and PG faster than selection for WW.

Footnotes

1 Paper No. 9417 of the Journal Series of the North Carolina Agr. Res. Service, Raleigh.

2 Present address: Centro Nacional de Pesquisa de Suinos e Aves, EMBRAPA, C.P. D-3, 89.700-Concordia, Santa Catarina, Brazil.

3 Dept. of Anim. Sci.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1985 by the American Society of Animal Science.