title: Estrous cycle based on blood progesterone profiles and changes in vulvar appearance of Malayan tapirs (Tapirus indicus).
abstract: The progesterone (P(4)) profiles and macroscopic vulvar changes of female Malayan tapirs were investigated in order to understand their fundamental reproductive physiology and to search for visual indicators of estrus. Blood was collected once or twice a week from seven female Malayan tapirs kept at four zoos. Serum or plasma P(4) concentrations were determined by radioimmunoassay. The P(4) concentrations changed cyclically throughout the years, and a total of 56 cycles was confirmed in the seven females. The length of the estrous cycle based on the P(4) profiles was 43.6+/-2.0 days; however, this mean includes great variation in length, from 21 to 84 days. Mucous discharge from the vulva and vulvar swelling were seen when the P(4) concentrations were low before the beginning of a rise in most cases. In conclusion, captive female Malayan tapirs have variations of approximately 1 to 3 months in estrous cycle length, and visual changes in the vulva are helpful in estimating estrus in female Malayan tapirs.
authors.affiliation: Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kusuda
authors.forename: Masakazu
authors.initials: M
authors.lastname: Ikoma
authors.forename: Koki
authors.initials: K
authors.lastname: Morikaku
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Koizumi
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Kawaguchi
authors.forename: Kuniyasu
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Kirito
authors.initials: K
authors.lastname: Matsui
authors.forename: Akira
authors.initials: A
authors.lastname: Nakamura
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hashikawa
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Miya
authors.initials: M
authors.lastname: Ueda
authors.forename: Mikako
authors.initials: M
authors.lastname: Kaneko
authors.forename: Takako
authors.initials: T
authors.lastname: Akikawa
authors.forename: Sachiko
authors.initials: S
authors.lastname: Shibagaki
authors.forename: Osamu
authors.initials: O
authors.lastname: Doi
mesh_terms: D000818:Animals; D001947:Breeding; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D008296:Malaysia; D010527:Perissodactyla; D011374:Progesterone / Q000097:blood*; D014844:Vulva / Q000033:anatomy & histology / Q000502:physiology*
chemical_list: D011374:Progesterone