Relationship between gestational age and transabdominal ultrasonographic measurements of fetus and uterus during the 2nd and 3rd trimester of gestation in cows

ObjectiveThe study was designed to estimate the relationship between gestational age and transabdominal ultrasonographic measurements of fetus and uterus during the 2nd and 3rd trimester of gestation in cows.MethodsSeventeen cows with confirmed conception dates were used. The cows were examined transabdominally in standing position using the 3.5 MHz convex sector transducer of real-time ultrasonography. Measurements of length and height of placentomes, distance between uterine walls, width of trunk and heart, intercostal distance and width of umbilical cord were obtained from the ultrasonographic images by using the screen caliper software.ResultsMeasurements at <90 and >250 d of gestation were for placentomes length (17.87 ± 2.26) and (75.92 ± 7.76) mm, height of placentomes (13.37 ± 1.12) and (36.50 ± 3.92) mm, distance between uterine walls (71.45 ± 10.68) and (144.63 ± 7.29) mm, and width of umbilical cord (7.80 ± 0.42) and (16.41 ± 0.41) mm, width of trunk (35.67 ± 7.11) and (146.50 ± 5.34) mm, width of heart (15.10 ± 5.50) and (74.57 ± 4.20) mm, and intercostal distance (3.85 ± 0.49) and (21.79 ± 0.48) mm, respectively. All the measurements were highly significantly correlated with gestational age (P < 0.01). The measurements showing the highest correlation with gestational age were the width of heart (r = 0.977), width of trunk (r = 0.965), and intercostal distance (r = 0.952), while the remaining measurements shown the least correlation with gestational age; distance between uterine walls (r = 0.887), width of umbilical cord (r = 0.882), placentomes length (r = 0.880), and placentomes height (r = 0.788).ConclusionTransabdominal ultrasonography is a practical and reliable method for obtaining the fetal and uterine measurements during the 2nd and 3rd trimesters of gestation. The correlation coefficients between gestational age and fetal measurements (width of trunk and heart and intercostal distance) were higher than those of uterine measurements, and the highest correlation was between heart width and gestational age in cows.