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Impact of preovulatory estradiol concentrations on mechanisms affecting fertility in cattle

Bridges, Glen Allen
http://rave.ohiolink.edu/etdc/view?acc_num=osu1190049332

Abstract Details

2007, Doctor of Philosophy, Ohio State University, Animal Science.
The effects of lesser concentrations of estradiol prior to ovulation on embryonic development and uterine characteristics at various times during early gestation in cattle were investigated. The first experiment examined the effect of reducing the interval of proestrus prior to inducing the ovulation of follicles of similar diameter on circulating hormone concentrations. Reducing the interval of proestrus decreased concentrations of estradiol prior to ovulation establishing this animal model as a method to manipulate preovulatory estradiol concentrations in animals with ovulatory follicles of similar diameter. This animal model was used to study characteristics of the uterus or embryo that might explain the reduction in fertility associated with suboptimal concentrations of estradiol prior to ovulation. In a second study, cows with reduced preovulatory estradiol concentrations had increased mRNA for oxytocin receptor, estradiol receptor beta, and cyclooxygenase-2 on day 5 of the estrous cycle compared to cows with elevated preovulatory estradiol concentrations. In cows with lesser estradiol concentrations, altered uterine gene expression on day 5 may indicate alterations in uterine function that could contribute to embryonic death later in pregnancy. In the next study, the impact of duration of exposure to elevated estradiol concentrations during proestrus on embryonic development on d 6 of gestation was investigated. Results suggested that reducing estradiol prior to ovulation does not influence early embryonic development. Across treatments however, peak estradiol concentrations were correlated to total number of nuclei per embryo. Lastly, conceptus and uterine characteristics on day 15.5 of gestation were compared between heifers with normal and deficient preovulatory estradiol concentrations. No differences in conceptus size and viability between heifers with differing preovulatory estradiol concentrations were observed. However, heifers with lesser preovulatory estradiol had reduced mRNA for estradiol receptor alpha in the uterine endometrium, nuclear progesterone receptor in the deep glandular epithelium, and amount of secreted phosphoprotein 1 in the uterus. These differences may represent functional changes occurring within the uterus that results in eventual embryonic mortality. Collectively, these experiments indicated that deficient preovulatory estradiol causes changes in the uterus during early gestation and suggests that embryonic mortality occurs after maternal recognition of pregnancy in estradiol deficient animals.
Michael Day (Advisor)
272 p.
Agriculture, General
Cattle; Fertility; Estradiol; Uterus

Recommended Citations

Citations

  • Bridges, G. A. (2007). Impact of preovulatory estradiol concentrations on mechanisms affecting fertility in cattle [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1190049332

    APA Style (7th edition)

  • Bridges, Glen. Impact of preovulatory estradiol concentrations on mechanisms affecting fertility in cattle. 2007. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1190049332.

    MLA Style (8th edition)

  • Bridges, Glen. "Impact of preovulatory estradiol concentrations on mechanisms affecting fertility in cattle." Doctoral dissertation, Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1190049332

    Chicago Manual of Style (17th edition)

osu1190049332
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© 2007, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.