Early pregnancy diagnosis and fetal viability in bitches through B-MODE real time ultrasonography

Ultrasound examinations were performed on two groups of crossbred bitches aged 2-6 years in order to establish the proper time for early pregnancy diagnosis and the assessment of certain parameters determining fetal viability. Group I was made up of 5 bitches days 17, 21, 22, 23 and 24 days after mating (PB) respectively and 3 bitches with 25 days PB (a total of 8 bitches). Group II was made up of 6 bitches with more that 35 days PB. For ultrasound diagnosis a PieMedical ultrasound scanner with a mini-convex 5.0-7.5 MHz transducer was utilized. The research was carried out at the University Veterinary Polyclinic, Faculty of Veterinary Sciences, University of Zulia. A distended uterus with anechoic content was evident in the bitch assessed at 17 days post-breeding; in this case the pregnancy was confirmed on day 25 PB. In the bitches initially examined between days 21 and 25 post-breeding, spherical anechoic structures (embryonic vesicles) each surrounded by a hypoechoic wall (placental tissue) and containing an embryo, were observed. The cardiac activity of those embryos could be measured when bitches were evaluated on day 25 post-breeding. In 5 of the bitches examined on day 35 PB and thereafter, cardiac activity and fetal movements were related to fetal viability. In one of these bitches, fetuses with positive cardiac activity and lack of movement were observed during the 10-minute evaluation. All puppies of that bitch were dead at birth 7 days post-evaluation. It is concluded that the 21-to-25 day post-breeding period is the adequate moment to give an accurate early pregnancy diagnosis in canine females through ultra-sonography. The use of global ultrasound examination comprising presence of heart beat, cardiac frequency and fetal movements, as well as subsequent evaluation on, day 35 PB, and posterior monitoring of fetal viability is highly recommended.