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


     

J. Anim Sci. 1981. 53:1458-1464.
© 1981 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 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 Allrich, R. D.
Right arrow Articles by Zimmerman, D. R.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Allrich, R. D.
Right arrow Articles by Zimmerman, D. R.

Selection for Increased Rate or Efficiency of Lean Growth in Rats: Correlated Responses in Reproductive Performance1

R. D. Allrich2,3,, C. T. Wang2, G. E. Dickerson4 and Dwane R. Zimmerman2

US Department of Agriculture, Clay Center, NE 68933 and and University of Nebraska, Lincoln 68583

Abstract

Two lines of rats selected for either rate or efficiency of postweaning lean growth and a control line were evaluated to determine whether any differences in reproductive performance had accompanied the genetic improvement in rate or efficiency of lean growth after 14 generations of selection (followed by six generations of relaxed selection). All progeny were reared in litters of nine until weaning at 21 days of age, and in like-sex or unlike-sex pairs thereafter. Like-sex paired females were placed with unrelated males of similar age for mating at approximately 70 days of age, while unlike-sex paired females remained with the original unrelated male until mated or autopsied at 85 days of age. Selection for either rate or efficiency of lean growth increased age at vaginal opening (38.9 and 38.6 vs 36.9 days for controls; P<.01) and weight at vaginal opening (133.1 and 126.6 vs 119.8 g for controls; P<.01) in like-sex paired females; similar findings were made for unlike-sex paired females. Ovulation rate, number of fetuses and pre- and postimplantation losses were not altered by selection. Age at first spontaneous mating did not differ among lines of male rats. Testes weight at 85 days of age were lower (P< .01) for males selected for efficiency of lean growth. The results indicate that there are alterations in reproductive characteristics as a consequence of selection for either rate or efficiency of lean growth in rats.

Footnotes

1 Published as Paper No. 5988, Journal Ser., Nebraska Agr. Exp. Sta. Research was supported in part by USDA Cooperative State Research Service Grant 701-15-42, USDA, SEA, Cooperative Research.

2 Dept. of Anim. Sci.

3 Present address: Roman L. Hruska US Meat Animal Research Center, P.O. Box 166, Clay Center, NE 68933.

4 Roman L. Hruska US Meat Animal Research Center, SEA, AR, Marvel Baker Hall, Univ. of Nebraska, Lincoln 68583.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1981 by the American Society of Animal Science.