title: Fetal age estimation of Hokkaido sika deer (Cervus nippon yesoensis) using ultrasonography during early pregnancy.
abstract: In sika deer, the normal method of estimating fetal age, based on fetal weight, is not applicable during the early pregnancy period. The objective of the present study was to describe the growth and development of sika deer fetuses and to establish a method for fetal age estimation during early pregnancy using ultrasonography. Five captive female Hokkaido sika deer (Cervus nippon yesoensis) were observed for estrus and mated (day 0) with an intact male. At two- or three-day intervals, fetuses were observed by rectal ultrasonographic scans until 59-61 days of gestation. The straight crown-rump length (SCRL), curved crown-rump length (CCRL), head length (HL), trunk depth (TD) and heart rate (HR) of the fetuses were measured. Linear regression equations were computed for each measurement together with fetal age. Analyses were conducted after transformation to a natural logarithm for SCRL and CCRL. All equations were significant (P<0.001), with SCRL becoming measurable earlier (day 20) than the others and yielding the best correlation (Days= -2.08+14.15 LnX: X=SCRL, Ln=natural logarithm). Therefore, we concluded that a precise estimation of fetal age in early gestation is best performed using SCRL measurements.
authors.affiliation: Laboratory of Wildlife Biology, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: Yojiro
authors.initials: Y
authors.lastname: Yanagawa
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Matsuura
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Suzuki
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Saga
authors.forename: Hideto
authors.initials: H
authors.lastname: Okuyama
authors.forename: Daisuke
authors.initials: D
authors.lastname: Fukui
authors.forename: Gen
authors.initials: G
authors.lastname: Bandou
authors.forename: Seiji
authors.initials: S
authors.lastname: Katagiri
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Toshio
authors.initials: T
authors.lastname: Tsubota
mesh_terms: D000818:Animals; D018568:Crown-Rump Length; D003670:Deer / Q000196:embryology*; D005260:Female; D047109:Fetal Development / Q000502:physiology*; D005865:Gestational Age; D016014:Linear Models; D008297:Male; D011247:Pregnancy; D016216:Ultrasonography, Prenatal / Q000662:veterinary*