{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/70042"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/70042","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Equine Luteinizing Hormone Profile Characteristics: Effects of Sampling Interval, Method of Analysis, Reproductive State, Gonadotropin-Releasing Hormone and Foal Removal","abstract":"Studies in several species have indicated that luteinizing hormone (LH) profile characteristics vary with reproductive state. LH profiles may change rapidly, with pulses often occurring on an hourly or even more frequent basis. Only recently have these transitory changes been examined in mares. The results from the studies in this thesis identified characteristics of the LH profile in pony mares during different reproductive states and as influenced by gonadotropin-releasing hormone (GnRH) and the suckling stimulus, and delineated some appropriate methods for LH pulse analysis.","abstract_html":"Studies in several species have indicated that luteinizing hormone (LH) profile characteristics vary with reproductive state. LH profiles may change rapidly, with pulses often occurring on an hourly or even more frequent basis. Only recently have these transitory changes been examined in mares. The results from the studies in this thesis identified characteristics of the LH profile in pony mares during different reproductive states and as influenced by gonadotropin-releasing hormone (GnRH) and the suckling stimulus, and delineated some appropriate methods for LH pulse analysis.","abstract_has_math":false,"creators":["Sargent, Gayla Fletcher"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Animal Sciences","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-12-15T21:01:06Z","date_published":"2014-12-15T21:01:06Z","updated_at":"2026-07-22T22:26:02Z","subjects":["Biology, Animal Physiology","Biology, Veterinary Science"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8711869"],"render_values":[{"text":"(UMI)AAI8711869","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/70042","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Sargent, Gayla Fletcher"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-15T21:01:06Z","10000-01-01","1987"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Animal Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Biology, Animal Physiology","Biology, Veterinary Science"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/70042","(UMI)AAI8711869"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Studies in several species have indicated that luteinizing hormone (LH) profile characteristics vary with reproductive state. LH profiles may change rapidly, with pulses often occurring on an hourly or even more frequent basis. Only recently have these transitory changes been examined in mares. The results from the studies in this thesis identified characteristics of the LH profile in pony mares during different reproductive states and as influenced by gonadotropin-releasing hormone (GnRH) and the suckling stimulus, and delineated some appropriate methods for LH pulse analysis.","Cyclic and postpartum pony mares were utilized. Blood was collected every 15 or 30 minutes by jugular venipuncture and plasma subsequently assayed for LH concentrations.","Several methods were employed for pulse analysis. A modified Pulsar program (Merriam and Wachter, 1982; Gitzen and Ramirez, 1986) was selected as the most appropriate method for equine LH pulse analysis.","Number of LH peaks and peak frequency increased linearly as sampling interval decreased. Four-hour or greater sampling periods provided adequate data for analysis of LH pulse characteristics requiring multiple peaks.","A 20 (mu)g dose of GnRH induced a LH pulse similar to endogenous patterns. Only maximum LH differed, being greater in GnRH-treated mares.","Estrous mares had more LH peaks and greater frequency than diestrous mares. Other examined pulse characteristics were similar. Both groups exhibited episodic release of LH, as did postpartum mares.","Short-term foal removal had no apparent effect on interval from parturition to subsequent estrus and ovulation.","In summary, equine LH profiles changed as frequently as every 30 to 60 minutes, with pulse frequency being greater during the follicular phase than during either the luteal phase or the early postpartum period. Equine LH pulse characteristics were effected by method of analysis, sampling interval, and sampling period. Endogenous LH pulses could be provoked with injection of low doses of GnRH. Suckling did not appear to modify the pulse characteristics of equine LH.","Made available in DSpace on 2014-12-15T21:01:06Z (GMT). No. of bitstreams: 1 8711869.pdf: 3441581 bytes, checksum: 656a2fd1038025816e822047919b68b6 (MD5) Previous issue date: 1987","Embargo set by: Seth Robbins for item 70208 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","136 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987."]},{"key":"dc:title","label":"Title","values":["Equine Luteinizing Hormone Profile Characteristics: Effects of Sampling Interval, Method of Analysis, Reproductive State, Gonadotropin-Releasing Hormone and Foal Removal"]}]}],"canonical_facts":{"dc:creator":["Sargent, Gayla Fletcher"],"dc:date":["2014-12-15T21:01:06Z","10000-01-01","1987"],"dc:description":["Studies in several species have indicated that luteinizing hormone (LH) profile characteristics vary with reproductive state. LH profiles may change rapidly, with pulses often occurring on an hourly or even more frequent basis. Only recently have these transitory changes been examined in mares. The results from the studies in this thesis identified characteristics of the LH profile in pony mares during different reproductive states and as influenced by gonadotropin-releasing hormone (GnRH) and the suckling stimulus, and delineated some appropriate methods for LH pulse analysis.","Cyclic and postpartum pony mares were utilized. Blood was collected every 15 or 30 minutes by jugular venipuncture and plasma subsequently assayed for LH concentrations.","Several methods were employed for pulse analysis. A modified Pulsar program (Merriam and Wachter, 1982; Gitzen and Ramirez, 1986) was selected as the most appropriate method for equine LH pulse analysis.","Number of LH peaks and peak frequency increased linearly as sampling interval decreased. Four-hour or greater sampling periods provided adequate data for analysis of LH pulse characteristics requiring multiple peaks.","A 20 (mu)g dose of GnRH induced a LH pulse similar to endogenous patterns. Only maximum LH differed, being greater in GnRH-treated mares.","Estrous mares had more LH peaks and greater frequency than diestrous mares. Other examined pulse characteristics were similar. Both groups exhibited episodic release of LH, as did postpartum mares.","Short-term foal removal had no apparent effect on interval from parturition to subsequent estrus and ovulation.","In summary, equine LH profiles changed as frequently as every 30 to 60 minutes, with pulse frequency being greater during the follicular phase than during either the luteal phase or the early postpartum period. Equine LH pulse characteristics were effected by method of analysis, sampling interval, and sampling period. Endogenous LH pulses could be provoked with injection of low doses of GnRH. Suckling did not appear to modify the pulse characteristics of equine LH.","Made available in DSpace on 2014-12-15T21:01:06Z (GMT). No. of bitstreams: 1 8711869.pdf: 3441581 bytes, checksum: 656a2fd1038025816e822047919b68b6 (MD5) Previous issue date: 1987","Embargo set by: Seth Robbins for item 70208 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","136 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987."],"dc:identifier":["http://hdl.handle.net/2142/70042","(UMI)AAI8711869"],"dc:subject":["Biology, Animal Physiology","Biology, Veterinary Science"],"dc:title":["Equine Luteinizing Hormone Profile Characteristics: Effects of Sampling Interval, Method of Analysis, Reproductive State, Gonadotropin-Releasing Hormone and Foal Removal"],"dc:type":["text"],"thesis:degree_discipline":["Animal Sciences"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:02Z"}