Ultrasonographic appearance of the gestational structures throughout accurately timed pregnancy in Korea Jin-do dogs I. Time of initial detection of the fetal and extra-fetal structures

진도개에서 임신일령에 따른 임신구조물의 초음파상 I. 태아 및 태아외구조물의 최초 관찰시기

Serial ultrasonographic examinations were performed on 9 pregnant Korea Jin-do bitches that were the Korean native breed, from days 15 to 60 pregnancy to determine the time of first detection and ultrasonographic appearance of the fetal and extra-fetal structures of pregnancy. Gestational age was timed from the day of ovulation (Day 0), which was estimated to occur when plasma progesterone concentration was first increased above 4.0 ng/ml. Gestational ages at earliest detection of the following fetal and extra-fetal structures were; gestational sac at days 17 to 22; placental layers in the uterine wall at days 20 to 24; zonary placenta at days 25 to 28; yolk sac membrane at days 22 to 24; amnionic membrane at days 27 to 29; embryo initial detection at days 21 to 23; fetal heartbeat at days 21 m 25; bipolar shape embryo at days 25 to 26; fetal movement at days 28 to 31; limb buds at days 31 to 35; anechoic area in head at days 31 to 36; stomach at days 34 to 37; urinary bladder at days 34 to 37; skeleton at days 36 to 38; dorsal sagittal tubular structure in vertebrae at days 36 to 38; lung hyperechoic vs liver at days 37 to 39; liver hypoechoic vs abdomen at days 37 to 40 and kidney at days 43 to 48, respectively.