2026-09-21T11:31:38Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/70023 2023-07-11 col_2142_5131 col_2142_14771 com_2142_5130 com_2142_685 com_2142_397

Pope, Nancy Salka 2014-12-15T21:00:58Z 2014-12-15T21:00:58Z 10000-01-01 1984 1984 An extended study was done to determine reproductive and hormonal parameters in pony mares during the peripartum period over three seasons: winter, summer and fall. Experiments were also conducted on control and hormonally manipulated barren mares during the same three seasons. Blood samples were obtained on a daily and frequent basis from foaling mares prepartum, during parturition and postpartum. Estrous behavior and ovulation parameters were also obtained. Progesterone:estradiol ratios were found to be decreasing at the time of parturition. A surge in LH was found to occur soon after the precipitous decline in progesterone seen at parturition. Androstenedione levels were elevated during parturition. LH pulsatile release on days 1, 4, 7 and 10 postpartum is described. Greater than 90% of mares showed ovulation within 20 days postpartum regardless of season. Treatment of barren mares with 10 daily progesterone injections with PGF(,2)(alpha) on day 7 and hCG on day 2 of estrus following progesterone withdrawal was done. One group received LH/FSH injections in addition to the treatment beginning on day 9 of progesterone and continuing until estrus was detected. In winter, the gonadotropin-treated group showed more ovulations than controls or the group treated without gonadotropins. Seasonal differences in androgen levels during vehicle injections of controls were very evident, possibly a stress-related response. Dexamethasone was shown to decrease testosterone and androstenedione levels in mares without affecting estradiol, progesterone or LH, and to abolish estrous behavior in intact mares during the winter. Made available in DSpace on 2014-12-15T21:00:58Z (GMT). No. of bitstreams: 1 8502269.pdf: 3592222 bytes, checksum: 2fda389503e08c1e65637a3d3ad9b857 (MD5) Previous issue date: 1984 Embargo set by: Seth Robbins for item 70189 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 123 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984. http://hdl.handle.net/2142/70023 (UMI)AAI8502269 Biology, Animal Physiology The Influence of Season on Estrus, Ovulation, and Reproductive Hormone Secretions in Barren and Periparturient Pony Mares (Postpartum, Adrenal, Parturition) text Animal Science Animal Science University of Illinois at Urbana-Champaign Dissertation Ph.D.