title: Real-time ultrasonic biparietal diameter of second trimester Suffolk and Finn sheep fetuses and prediction of gestational age.
abstract: Six Suffolk fetuses of known gestational age were examined every other day from Day 43 to Day 96 of gestation using transabdominal real-time ultrasound. Biparietal diameter (BPD) was measured on symmetrical fetal head images. The relationship between days gestational age (GA) and mean BPD in millimeters is described by the equation: [GA = 22.5 + 1.81 BPD]. Repeated ultrasound examination of 9 Finn ewes between 35 and 95 d of gestation revealed the relationship: [GA = 21.4 + 1.85 BPD]. Biparietal diameters were determined for 56 Suffolk X Hampshire fetuses which ranged from 41 to 77 d of gestation. The predicted fetal age using the Suffolk equation was within 1 d of the recorded age for 22 56 , +/-2 d for 34 56 , and +/-3 d for 44 56 fetuses.
authors.affiliation: Department of Veterinary Clinical Sciences College of Veterinary Medicine The Ohio State University Columbus, OH 43210 USA.
authors.forename: G K
authors.initials: GK
authors.lastname: Haibel
authors.forename: N R
authors.initials: NR
authors.lastname: Perkins