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


     

Journal of Dairy Science Vol. 72 No. 11 2928-2935
© 1989 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 Ringuet, H.
Right arrow Articles by Brazeau, P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ringuet, H.
Right arrow Articles by Brazeau, P.

Effect of Human Somatotropin-Releasing Factor and Photoperiods on Carcass Parameters and Mammary Gland Development of Dairy Heifers1

H. Ringuet3, D. Petitclerc2, M. T. Sorensen4, P. Gaudreau5, G. Pelletier, J. Morisset3, Y. Couture6 and P. Brazeau5

Agriculture Canada Research Station, Lennoxville, Quebec, Canada J1M 1Z3

ABSTRACT

Forty-eight heifers (3 mo old) were subjected for 35 wk to twice daily s.c. injections of saline or human somatotropin-releasing factor (5 µg· kg–1 BW) and photoperiod of 8 h (short day) or 16 h (long day) of light daily according to a 2 x 2 factorial design. There was no treatment effect on slaughter weight, withers height, and carcass length. Somatotropin-releasing factor increased thymus weight, metacarpal length, and protein content of the carcass but decreased carcass fat content. Long day photoperiod increased chest girth, pituitary weight, and carcass yield. Effects of somatotropin-releasing factor and photoperiod were not additive on volume of mammary parenchymal tissue; there was also a treatment interaction on liver and lung weights. However, extraparenchymal mammary tissue was decreased by human somatotropin-releasing factor and short day photoperiod. In conclusion, use of somatotropin-releasing factor and photoperiod treatments affected carcass parameters and composition and mammary growth.

FOOTNOTES

1 Lennoxville Research Station Contribution Number 265.

2 Reprint requests.

3 Department of Biology, Sherbrooke University, Sherbrooke, Quebec J1K 1Z3.

4 National Institute of Animal Science, Research Center Foulum, PO Box 39, DK-8833, Denmark.

5 Neuroendocrinology Laboratory, Notre Dame Hospital, Montreal.

6 University of Montreal, Veterinary School, St. Hyacinthe, Quebec.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1989 by the American Dairy Science Association ®.