B-mode ultrasound and ecobiometric parameters to assess embryonic and fetal development and estimate gestational age in goats.

The aim of this study was to monitor maternal-fetal ecobiometric parameters during physiological pregnancy in goats using ultrasound to predict gestational age by establishing mathematical equations. Twenty-five Saanen goats were included in the study. Assessments were performed weekly from the 21st day of pregnancy until parturition. The abdominal, thoracic, biparietal, and eye socket diameters; distance from the neck to snout; crown-rump, humerus, radius-ulna, metacarpal, femur, tibia, metatarsal, and placentome lengths; kidney height and length; and heart area were measured. Heart rate was obtained using the pulsed Doppler mode. The variables were correlated with gestational age using Spearman's test, and the adjustment of these variables to simple and multiple regression models was done to determine the mathematical formulas for calculating the gestational age. The highest obtained coefficients of determination (R2) were for humerus length (96.2), heart area (95.6), and distance from the neck to the snout (95.3). Only the placentome length and fetal heart rate presented low determination coefficients (R2 = 54.3, R2 = 45.0). The results indicated significant correlations between measures of maternal-fetal structures and gestational age, and can be used as reference values for detection of abnormalities during fetal development.

Maternal and fetal ultrasonographic characteristics, vulvar temperature, and vaginal mucous impedance as variables associated with the onset of parturition in term and induced pre-term ewes.

The aim of this study was to assess and compare ultrasonographic characteristics of maternal and fetal structures, vulvar temperatures, and vaginal mucous impedance in pregnant ewes in the term parturition group (TPG, n = 15) and induced pre-term parturition group (IPPG; n = 15). All the measurements were taken every 12 h throughout the last gestational week. Maternal and fetal structures and the fetal heart rate (HR) were assessed using ultrasonography. The vulvar temperature and vaginal mucous impedance were determined using a non-contact infrared thermometer, and an electronic estrous detector, respectively. The vulvar temperature was less in the TPG and greater in the IPPG; the end-diastolic velocities (EDVs) of the arteries of the placentome and uterus gradually increased before parturition in the IPPG (P = 0.02, P = 0.02 and P = 0.009, respectively). The placentome shear wave velocity (SWV) was greater in the ewes of the IPPG than TPG 48, 36, and 0 h before parturition (P = 0.001). The following variables were associated with the onset of parturition within the next 12 h in the ewes of the IPPG: resistance index (< 0.54) and EDV (> 0.34 cm/s) of the uterine artery; and vulvar temperature (> 37.3 °C). A fetal kidney SWV of < 1.31 m/s was associated with the onset of parturition in the next 12 h in all the ewes. Results indicate vulvar temperature and certain maternal and fetal factors detected using ultrasonograpy may aid in determining fetal maturity and/or the time of parturition in ewes.

Placental ARFI elastography and biometry evaluation in bitches.

Placental rigidity and biometry of twelve pregnant bitches were evaluated using B-mode and Acoustic Radiation Force Impulse (ARFI) ultrasonography, performed once daily, from day 15 of gestation until parturition. Specific software (Virtual Touch Tissue Quantification® VTTQ and Virtual Touch Tissue Imaging Quantification® VTTIQ) were used. Values for results for variables were correlated and regression models related to gestational day were used to make evaluations. Maternal-fetal placental thickness increased to day 63 (P < 0.0001; R² = 0.91); maternal placental thickness increased until day 40 (P = 0.0340; R² = 0.54); and fetal placental thickness increased to day 50 (P < 0.0001; R² = 0.83) of gestation. Shear wave velocity (SWV) of the dorsal (P < 0.0010) was greater than lateral, which in turn was greater (P = 0.020) than the ventral area. The SWV of the dorsal area as determined using VTTQ, decreased from day 21-35 and increased to day 56 of gestation (P = 0.0291; R² = 0.4021); lateral SWV decreased from day 24-45 and increased until the time of parturition (P < 0.001; R² = 0.6055). The SWV of the dorsal area, as determined using VTTIQ, decreased from day 21-43 and then increased to day 60 of gestation (P = 0.0016; R² = 0.5075); and ventral area SWV increased from day 21-23 and decreased until the time of parturition (P < 0.001; R² = 0.8055). Placental alterations reflect structural and biochemical gestational adaptations and can become useful techniques for obstetrics.

Elastographic and echotextural characteristics of foetal lungs and liver during the final 5 days of intrauterine development in dogs.

Objective was to evaluate the echotexture and characteristics during terminal development of canine foetal respiratory and hepatic systems through elastographic examinations. Fifteen pregnant bitches were evaluated by ultrasonography twice daily, from the 53rd gestational day until whelping, and images obtained from 120 to 0 h before parturition were analysed. Images of foetal lungs and liver were recorded and then used for computer-assisted analyses to determine quantitative attributes. Acoustic Radiation Force Impulse (ARFI) elastographic of internal organs were classified as 'soft' (white areas) or 'hard' (dark areas) and quantitative analyses determined the mean shear wave velocities (SWV) of foetal lungs and liver. After delivery, canine neonates were clinically evaluated, and their health status was monitored weekly until 60 days post-partum. Sonographic parameters over time were compared by ANOVA and Pearson's correlations were used to determine associations between SWVs and echotextural variables. Foetal lungs and liver had a homogeneous echotexture and pulmonary parenchyma appeared hyperechoic when compared with that of the liver. Mean numerical pixel values (NPVs) of lungs decreased from 120 to 24 h and subsequently increased until parturition (P = 0.04). Lungs and liver mean (± SD) SWVs (0.98 ± 0.12 and 0.84 ± 0.11 m/s, respectively) didn't vary (P > 0.05) over time. Fluctuations in pulmonary NPVs indicated there was a pattern corresponding to structural and functional changes that occur during the terminal stage of pre-natal canine development and hence can be a useful diagnostic tool in veterinary. Foetal lung and liver SWVs were relatively consistent and there was no detectable changes during the pre-partum period for this variable or in echotexture.