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


     

J. Anim Sci. 1974. 38:330-338.
© 1974 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 Squires, E.L.
Right arrow Articles by Ginther, O.J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Squires, E.L.
Right arrow Articles by Ginther, O.J.

Ovarian Changes during the Estrous Cycle and Pregnancy in Mares1

E.L. Squires2, R.H. Douglas2, W.P. Steffenhagen and O.J. Ginther

University of Wisconsin, Madison 53706

Abstract

Pregnant pony mares (weight, 115 to 300 kg) were necropsied on the following days after the end of estrus (number of mares in parentheses): 10 (three), 14 (four), 18 (four), 24 (three), 30 (two), 40 (two), 50 (three), 60 (three), 80 (three), 100 (three), 160 (two) and 220 (one). The primary corpus luteum was marked with India ink on day 2 or 3 in the mares which were necropsied on days 24 to 220. In a second experiment pregnant mares were necropsied and the stage of pregnancy was estimated as follows: 150± 15 days (six mares), 180 ±15 days (four mares), 210±15 days (four mares). The weight of the primary corpus luteum in pregnant mares was significantly less at day 14 than at day 10 and tended (P<10) to be greater at day 18 than at day 14. The primary corpus luteum, based on color, was maintained until day 160 or 180. Secondary corpora lutea began to appear on days 40 to 60 and the numbers increased gradually until day 160. Within mares, the primary corpus luteum and secondary corpora lutea appeared to regress at approximately the same time and only remnants of luteal structures remained by days 180 to 220. Diameter of largest follicle was greatest at day 60 and decreased thereafter as pregnancy advanced reaching smallest diameter by day 160 to 180. There was a gradual decrease in number of large follicles (>10 mm) after, day 60 and the decrease could be accounted for, at least in part, by the increasing number of secondary corpora lutea.

Footnotes

1 From the Department of Veterinary Science, University of Wisconsin, Madison, Wisconsin 53706. Supported by the College of Agricultural and Life Sciences, University of Wisconsin, Madison and by Grant No. 630-0505A from the Ford Foundation and by Public Health Service Training Grant No. 5-T01-HD-00104-08. These data were presented in part at the Midwestern Section of the AMERICAN SOCIETY OF ANIMAL SCIENCE, November 24 and 25, 1972, Chicago, Illinois. Technical assistance was provided by Mr. Robert Elderbrook.

2 Predoctoral Trainees, Endocrinology-Reproductive Physiology Program, University of Wisconsin, Madison.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1974 by the American Society of Animal Science.