title: Induction of the ovulatory LH surge in Asian elephants (Elephas maximus): a novel aid in captive breeding management of an endangered species.
abstract: A unique feature of the reproductive physiology of Asian elephants (Elephas maximus) is the occurrence of two LH surges before ovulation, instead of one. An anovulatory LH (anLH) surge, the function of which is unknown, occurs consistently 3 weeks before the ovulatory LH (ovLH) surge that induces ovulation. Thus, the ability to induce an ovLH surge would be useful for scheduling natural mating or artificial insemination. The present study tested the efficacy of a gonadotrophin-releasing hormone agonist (GnRH-Ag) to induce LH surges during the follicular phase of the oestrous cycle, which resulted in varied LH responses, but generally none were as high as previously documented natural surges. Thus, for the ovulation-induction trials, nine females were administered 80 microg GnRH-Ag intravenously at three time periods during the oestrous cycle, namely the anovulatory follicular phase, the ovulatory follicular phase and the luteal phase. During the late anovulatory follicular phase, nine of 10 females (90%) responded with an immediate LH surge followed 15-22 days later by an ovLH surge or a post-ovulatory increase in progestagens. In contrast, despite responding to the GnRH-Ag with an immediate increase in LH, none of the females treated during other periods of the oestrous cycle exhibited subsequent ovLH surges. One cow got pregnant from natural mating following the induced ovLH surge. In conclusion, ovLH induction is possible using a GnRH-Ag, but only during a specific time of the anovulatory follicular phase.
authors.affiliation: Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, 50100, Thailand. thitaram@chiangmai.ac.th
authors.forename: Chatchote
authors.initials: C
authors.lastname: Thitaram
authors.forename: Pornsawan
authors.initials: P
authors.lastname: Pongsopawijit
authors.forename: Saran
authors.initials: S
authors.lastname: Chansitthiwet
authors.forename: Janine L
authors.initials: JL
authors.lastname: Brown
authors.forename: Kannikar
authors.initials: K
authors.lastname: Nimtragul
authors.forename: Khajhonpat
authors.initials: K
authors.lastname: Boonprasert
authors.forename: Pongpon
authors.initials: P
authors.lastname: Homkong
authors.forename: Sittidet
authors.initials: S
authors.lastname: Mahasawangkul
authors.forename: Suvichai
authors.initials: S
authors.lastname: Rojanasthien
authors.forename: Ben
authors.initials: B
authors.lastname: Colenbrander
authors.forename: Gysbert C
authors.initials: GC
authors.lastname: van der Weijden
authors.forename: Frank J C M
authors.initials: FJ
authors.lastname: van Eerdenburg
mesh_terms: D000822:Animal Husbandry / Q000379:methods*; D000818:Animals; D001947:Breeding / Q000379:methods*; D002064:Buserelin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004606:Elephants / Q000097:blood / Q000502:physiology*; D004971:Estrus / Q000502:physiology; D005260:Female; D005498:Follicular Phase / Q000502:physiology; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists; D007986:Luteinizing Hormone / Q000097:blood*; D010060:Ovulation / Q000187:drug effects / Q000502:physiology; D010062:Ovulation Induction / Q000379:methods / Q000662:veterinary*
chemical_list: D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D002064:Buserelin