JDS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Journal of Dairy Science Vol. 69 No. 9 2370-2378
© 1986 by American Dairy Science Association ®
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 Smothers, C. D.
Right arrow Articles by Owen, J. R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Smothers, C. D.
Right arrow Articles by Owen, J. R.

Correlated Response in Feed Efficiency Accompanying Selection for Milk Yield in Jerseys

C. D. Smothers1, B. R. Bell2, D. O. Richardson2, B. F. Hollon3, E. D. Moore4 and J. R. Owen4

Agricultural Research Service, US Department of Agriculture, Lewisburg, TN 37091
University of Tennessee, Knoxville 37901-1071

ABSTRACT

Gross feed efficiency (milk energy output divided by energy consumed) was measured in 232 Jersey cows resulting from direct selection for milk yield and a control line of 121 daughters of 20 Jersey bulls taken randomly from commercial artificial insemination sampling programs in 1967. Data were collected between 1971 and 1982 from primiparous cows in middle to late lactation in 21 feeding trials of 28 d. Cows were fed hay and silage ad libitum plus grain according to production at the rate of 1 kg grain/3 kg milk. Models for least squares analyses included trial, line, days in milk, and either body weight change (model 1) or energy balance (model 2), estimated as the difference between energy requirements and actual energy intake. Body weight change was an insignificant source of variation, and gross feed efficiency did not differ between genetic lines using model 1. Significant line differences in gross efficiency were obtained after adjusting for energy balance; however, problems of multi-collinearity invalidates meaningful inference. Results indicate genetic lines of Jerseys did not differ in gross feed efficiency when fed according to yield and suggest selection has not affected efficiency of direct conversion of nutrients into milk.

FOOTNOTES

1 Dairy Experiment Station, Lewisburg, TN.

2 Department of Animal Science, University of Tennessee, Knoxville, TN 37901.

3 Retired, Agricultural Research Service, US Department of Agriculture.

4 Agricultural Research Service, US Department of Agriculture, Dairy Experiment Station, Lewisburg, TN 37091.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1986 by the American Dairy Science Association ®.