Doppler Ultrasonographic Assessment of Maternal and Foetal Blood Flow in Canine Pregnancy and Its Application in the Critical Management of Gestation#

Abstract

Background: Doppler ultrasonographic assessment of maternal and foetal blood flow/perfusion has become an indispensable diagnostic tool in veterinary obstetrics. Periodic Doppler examination of critical canine pregnancies to interpret vascular information such as blood velocity, flow direction/pattern and vascular pathologies would ensure safety of dam and survival chances of conceptuses.Methods: The present study included twenty apparently healthy bitches of different breeds presented at University Veterinary Hospital, Thrissur, Kerala for the management of breeding and pregnancy. Doppler examinations were conducted from fourth week of pregnancy at 10 d interval to evaluate blood flow in uteroplacental artery (UPA), umbilical artery (Uma) and foetal abdominal aorta by measuring pulsatility (PI) and resistive indices (RI). Result: Throughout the study the UPA showed biphasic wave. Up to 40 days of gestation the UPA showed diastolic notch and from 41-50 days it disappeared completely. The PI and RI decreased significantly at 5 per cent level between each 10 d interval. Similarly, the PI and RI of Uma decreased significantly at 5 per cent level between each 10 d interval. The PI of foetal abdominal aorta increased significantly at 5 per cent level from £ 30 d to 31-40 d of gestation and thereafter it decreased significantly up to whelping. During early pregnancy the diastolic wave form was absent for Uma and abdominal aorta although at later stages both these vessels showed biphasic wave forms. The study also included the early diagnosis of two abnormal pregnancies, viz., a complete foetal resorption in a Labrador bitch and an incomplete abortion in a Rottweiler bitch by Doppler ultrasound. The incomplete abortion was critically managed and the bitch whelped five healthy puppies fourteen days from the date of the incomplete abortion of three puppies. Thus, the study demonstrated the potential applicability of Doppler Ultrasound in the management of normal and abnormal pregnancies and predicting survival chances of neonates after whelping.