Early pregnancy diagnosis and embryonic and fetal development using real time B mode ultrasound in goats

Abstract

Real time B mode ultrasound scanning was used for the diagnosis of early pregnancy and monitoring of embryonic and fetal development in goats. Estrus in 8 cyclic cross-bred does was synchronized using a single injection of PGF2α followed by mating with a buck. All the does were subjected to weekly transrectal (from day 14 of mating) and transabdominal ultrasonography (from day 28) up to the 4th month of gestation and once during the 5th month of gestation. Of the 8 animals, 6 does were confirmed pregnant. The embryonic vesicle was detected on day 21 and day 28 and the embryo proper on day 28, day 35 using the transrectal and transabdominal methods, respectively. Heart beat was observed as early as day 21 of gestation and it was recordable by day 28 using the transrectal approach. However, via transabdominal scanning the detection and recording of the heart beat was possible only on day 35 of gestation. Singles and twins were differentiated on day 35 and day 42 by the transrectal and transabdominal approaches, respectively. Placentomes as a circular ‘C’ shape structure was detectable on day 42 with an average diameter of 0.97 cm, using the rectal probe. Using the abdominal probe, placentomes were detectable on day 50 (average diameter of 1 cm of gestation). Skeletal structures such as the skull, rib cage and vertebral column were first viewed on day 56 in both approaches. A significant ( P < 0.001) high correlation ( r = 0.99) was recorded between the gestational age and head, thoracic and placentome parameters. It may concluded that the earliest identification of an embryonic vesicle (day 21) by transrectal scanning and confirmation of its viability by fetal heart beat (day 28) were the most reliable ultrasonographic features for early pregnancy diagnosis in goats. Transabdominal ultrasonographic measurements of placentome, head and thoracic diameter may be of use in the assessment of fetal age.