title: Ultrasonographic evaluation of equine fetal growth throughout gestation in normal mares using a convex transducer.
abstract: It has not been common to perform regular ultrasound examination of the fetus in equine practice, due to the increasing volume of the uterus caused by fetal development. The convex three-dimensional transducer is bulb-shaped and is able to observe wide areas. In addition, its operation is simple, making it easy to create appropriate angles for various indices using a transrectal approach. The aim of this study was to measure Thoroughbred fetal growth indices throughout gestation using a convex transducer and to clarify the detectable period of some indices for clinical use. We demonstrated changes in fetal indices, such as crown rump length (CRL), fetal heart rate (FHR), fetal eye and kidney and the combined thickness of uterus and placenta (CTUP). CTUP increased from 30 weeks of gestation, and FHR peaked at 8 weeks and then decreased to term. CRL could be observed until 13 weeks due to its wide angle, longer than in previous reports. Fetal eye and kidney could be observed from 10 and 28 weeks, respectively, and these increased with pregnancy progress. The present results showed the advantage of transrectal examination using a convex transducer for evaluation of normal fetal development. Although ultrasonographic examination in mid- to late-gestation is not common in equine reproductive practice, our comprehensive results would be a useful basis for equine pregnancy examination.
authors.affiliation: Equine Science Division, Hidaka Training and Research Center, Japan Racing Association, 535-13 Nishicha, Urakawa-cho, Urakawa-gun, Hokkaido 057-0171, Japan.
authors.forename: Harutaka
authors.initials: H
authors.lastname: Murase
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Endo
authors.forename: Takeru
authors.initials: T
authors.lastname: Tsuchiya
authors.forename: Yasumitsu
authors.initials: Y
authors.lastname: Kotoyori
authors.forename: Mitsumori
authors.initials: M
authors.lastname: Shikichi
authors.forename: Katsumi
authors.initials: K
authors.lastname: Ito
authors.forename: Fumio
authors.initials: F
authors.lastname: Sato
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nambo
mesh_terms: D000818:Animals; D004622:Embryo, Mammalian / Q000000981:diagnostic imaging*; D005260:Female; D006736:Horses / Q000196:embryology* / Q000502:physiology*; D011247:Pregnancy; D014159:Transducers / Q000662:veterinary*; D016216:Ultrasonography, Prenatal / Q000662:veterinary*