Early Pregnancy Diagnosis by the Ultrasonographical Device and Observation of Fetal Growth in Cynomolgus Monkeys (Macaca fascicularis)

Usefulness of the ultrasongraphical device (USD) for early diagnosis of pregnancy and for observation of fetal growth was examined in the cynomolgus monkey (Macaca fas-cicularis) . Firstly, 50 females, each of which was mated for 24 hours in an individual cage, were used. They were diagnosed for pregnancy by the use of USD 15 to 29 days and 35 days after mating. Then, 20 of them were judged to be pregnant. The early pregnancy diagnosis was based on the detection of gestational sac (GS) in the uterus. The GS was detected 20.0±1.8 days of tes mating. The duration from the day on which GS was first detected to the day on which the heart beat of embryo (HBE) was detected averaged 5.6±1.5 days. In 17 of these 20 pregnancies, GS was detected 17 to 23 days after mating. As regards the remaining three pregnant cases, GS and HBE were simultaneously detected on the 28 th day of pregnancy in two cases, and on the 35 th day in one case. Secondly, 225 females who were mated by the routine 3 day-mating system were used. Pregnancy diagnosis by USD was conducted on the 21 st, 28th and 35 th day after mating. Ninety-six of the 225 females were judged to be pregnant. In 33 (34.1%) of the 96 pregnant cases, GS was detected on the 21 st day of pregnancy. In 57 females (59.4%), GS was detected on the 28 th day of pregnancy, and in the re-maining 6 (6.2%) cases GS was detected on the 35 th day. Furthermore, it was able to judge conditions of fetal growth by measuring the size of GS and biparietal diameter. In conclusion, USD is a useful means for the early diagnosis of pregnancy and the observation of conditions of fetal growth in the cynomolgus monkey.