title: Effect of age and time of day on the timing of the surge in luteinizing hormone, behavioural oestrus and mating in red deer hinds (Cervus elaphus).
abstract: The oestrous cycles of fourteen red deer hinds (six yearling; eight more than 2 years old) were synchronized during the early breeding season by removal of a progesterone-containing intravaginal device and blood samples were taken at intervals of 3 h commencing 13 or 25 h later and continued for 54 h. The controlled internal drug release devices (CIDRs) were removed at 08:00 h (group 1; three yearlings and four adults) or 12 h later at 20:00 h (group 2; three yearlings and four adults). There was no significant effect of time of removal of CIDR on the interval to the onset of oestrus (group 1, 34.5 +/- 4.05 h; group 2, 42.14 +/- 7.8 h) on the time of peak concentration (group 1, 41.81 +/- 5.69 h; group 2, 41.71 +/- 7.81 h) or on duration of the luteinizing hormone (LH) surge (group 1, 15.00 +/- 0.95 h; group 2, 14.57 +/- 0.78 h). The six yearling animals exhibited oestrus and LH surge significantly later than the adults (55 +/- 4.2 versus 32 +/- 6.3 h for the LH surge for yearling and adult females, respectively). In a further experiment, 20 hinds were synchronized during the breeding season by removal of CIDR at two times of day 12 h apart and placed with a stag. Mating took place at a mean time of 42.1 +/- 2.4 h and 37.0 +/- 1.3 h later in the two groups. There was no significant effect of time of removal of CIDR upon time to onset of oestrus.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Institute of Zoology, Zoological Society of London, UK.
authors.forename: C M
authors.initials: CM
authors.lastname: Argo
authors.forename: A S
authors.initials: AS
authors.lastname: Loudon
mesh_terms: D000367:Age Factors; D000818:Animals; D002940:Circadian Rhythm; D003670:Deer / Q000502:physiology*; D004971:Estrus / Q000097:blood / Q000502:physiology*; D004973:Estrus Synchronization; D005260:Female; D007986:Luteinizing Hormone / Q000097:blood*; D012726:Sexual Behavior, Animal
chemical_list: D007986:Luteinizing Hormone