Add like
Add dislike
Add to saved papers

Luteolysis during two stages of the estrous cycle: subsequent endocrine profiles associated with radiotelemetrically detected estrus in heifers.

Our objective was to correlate hormonal changes with the timing and onset of estrus in heifers before and after luteolysis was induced with PGF2 alpha at two stages of the estrous cycle: d 6 to 9 (early; n = 10) or d 14 to 15 (late; n = 10). Blood was collected at intervals of 2 or 12 h to quantify serum concentrations of progesterone, estradiol-17 beta, and LH while heifers were observed visually for estrus and monitored for standing activity by pressure-sensitive, radiotelemetric devices. Although the concentrations of estradiol-17 beta that were associated with the putative appearance of the first dominant follicle declined before luteolysis was induced early in the cycle, some heifers that were given PGF2 alpha were in estrus as early as 35 h. Compared with heifers treated late in the estrous cycle, heifers that were treated early in the cycle produced less progesterone before PGF2 alpha treatment and had greater peak concentrations of estradiol-17 beta at estrus. In addition, heifers that were treated early in the cycle had shorter intervals from PGF2 alpha treatment to estrus, to peak estradiol-17 beta, and to peak LH and to initiation of estrus after the peak in estradiol-17 beta than did heifers treated later in the cycle. The increase in estradiol-17 beta associated with the putative first-wave follicle of the subsequent cycle and the duration of that cycle in early cycle heifers was less than after late cycle luteolysis. Results indicated that greater concentrations of estradiol-17 beta during estrus may be related to the durations of previous cycles and less progesterone exposure before luteolysis. The onset of estrus corresponded closely to, but preceded, the preovulatory LH surge by approximately 3 h.

Full text links

We have located links that may give you full text access.
Can't access the paper?
Try logging in through your university/institutional subscription. For a smoother one-click institutional access experience, please use our mobile app.

For the best experience, use the Read mobile app

Mobile app image

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app

All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.

By using this service, you agree to our terms of use and privacy policy.

Your Privacy Choices Toggle icon

You can now claim free CME credits for this literature searchClaim now

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app