Seasonal effects on the endocrine pattern of semi-captive female Asian elephants (Elephas maximus): Timing of the anovulatory luteinizing hormone surge determines the length of estrous cycle

Thitaram, C.; Brown, J.L.; Pongsopawijit, P.; Chansitthiwet, S.; Wongkalasin, W.; Daram, P.; Roongsri, R.; Kalmapijit, A.; Mahaasawangkul, S.; Rojansthien, S.; Colenbrander, B.; van der Weijden, G.C.; van Eerdenburg, F.J.C.M.