Estimativa da idade gestacional por biometria fetal através de exames ultrassonográficos em cadelas (Canis familiaris, Linnaeus, 1758) das raças Bulldog francês, Pug e Shih-tzu

Abstract

Looking at fetal development and size characteristics, ultrasound is useful for estimating date of birth in bitches with multiple or uncertain date of copulations. However, the diversity in breed size can interfere in calculating gestational age through fetal measurements, making it necessary to establish measurement standards and calculations for dogs with the same size and similar breed characteristics. The objective of this study was to use ultrasound to discover which parameters could be used to estimate parturition date in brachycephalic French Bulldog, Pug and Shi-Tzu bitches. Fifteen bitches were examined in total, divided into three groups of five, which copulated with males of the same breed. We used a GE® ultrasound device, LOGIQ E model, with a linear transducer with a frequency between 5,0 and 11,0MHz every seven days from the point where gestation was confirmed until parturition. The following fetal/embrionary parameters were measured: embrionary vesicle, placenta width, biparietal diameter, thoracic diameter, abdominal diameter, umerus length, femur length and heart rate. We studied analysis of variance and simple correlation between age and various measurements, and significance of the coefficients for linear regression and coefficients for determination (R2), using a significance level of p<0,05. The measurements found were not significantly different between breeds in any of the exams. All measurements for the selected parameters, except heart rate, showed a significant (p<0,001) correlation with gestational age. Biparietal diameter had the greatest coefficient for determination (R2= 0,96), and placental width the lowest (R2= 0,54). We conclude that the measurements analyzed in this study can be used to estimate parturition date through equations common to brachycephalic bitches of the breeds considered in this study.