Establishment of a new equation to estimate gestational age in female dogs

• Published in: Reproduction in domestic animals 2023-11, Vol.58 (11), p.1576-1582
• Main Authors: Pollis, Elza S. C., Padilha, Felipe G. F., Campos, Isabela S., Bartz, Camila, Silva, Franciele B. F., Pinna, Aline E., Leite, Juliana da Silva, Ferreira, Ana M. R.
• Format: Article
• Language: English
• Subjects: Age; Dogs; Evaluation; Females; Fetuses; Gestation; Gestational age; Mathematical models; Placenta; Pregnancy; Regression models; Statistical analysis; Statistical models; Thickness; Ultrasonic imaging; Ultrasound
• ISSN: 0936-6768; 1439-0531
• DOI: 10.1111/rda.14473

The objectives of this study were to propose a statistical model to predict the behaviour of the thickness of the uteroplacental junction as a function of the gestation period in female dogs and to determine the relationship between the thickness of the placenta and gestational age in healthy female dogs whose pregnancies had elapsed without maternal‐fetal alterations. Eight Border Collie female dogs were selected, aged 3–6 (4.48 ± 0.89) and weighing 16–22 kg (19.06 ± 1.9 kg). Female dogs with gestational ages from 20 to 62 days were examined weekly using B‐mode ultrasonography. Ultrasound measurements of the uteroplacental junction were organized into four distinct groups: GT1 (27–36 days of gestation), GT2 (37–46 days of gestation), GT3 (47–56 days of gestation) and GT4 (57–62 days of gestation). Based on multiple linear regression, a statistical model was proposed to predict the behaviour of the thickness of the uteroplacental junction ( y ) as a function of the length of gestation ( x ) in female dogs, where b0 is the intercept (linear coefficient) and bp is the slope of the predictors. The analysis relating GT, age and weight could predict placental thickness and resulted in a statistically significant model [ F (1,28) = 153,736; p