Early pregnancy diagnosis and monitoring in the queen using ultrasonography with a 12.5 MHz probe

Abstract

Eleven pregnancies in six queens were monitored daily from day 7 to day 28, corresponding to the end of the embryonic period, using ultrasonography with a 12.5 MHz probe. The first mating was considered as the presumed start of gestation, as has been described to be the case in 92.3% of pregnancies. The embryonic vesicles were identified on day 11, while the embryo appeared on day 15 or 16. The stage of pregnancy could be evaluated approximately by measuring the length of the embryonic vesicle or the crown–rump length of the embryo from days 11 and 17, respectively, up until the end of the embryonic phase of gestation. The visualisation of certain organs could also be used to date gestation; for example, the limbs, neural tube and stomach were visible from days 19, 20 and 26, respectively. The 12.5 MHz probe did not enable the diagnosis of gestation to be performed any earlier than with 7.5 and 10 MHz probes. However, there was a significant difference in comparison with a 5 MHz probe.