Relationship between fetal biometric assessment by ultrasonography and neonatal lamb vitality, birth weight and growth

Abstract

Ultrasonographic examination of pregnant ewes can enable the identification of perinatal abnormalities and establish prenatal assistance responsible for minimizing morbidity and perinatal mortality. Therefore, we aimed to evaluate the feasibility of a fetal biometric analysis by ultrasonography to predict neonatal vitality and lamb growth during the first month of life. A longitudinal study was conducted with 13 healthy ewes, subjected to ultrasonographic examination every 15 days from 60 th day of pregnancy until lambing, evaluating thoracic diameter, abdominal diameter, biparietal diameter, humerus, femur and placentome length. At birth, 22 lambs were assessed through Apgar score at 5 minutes and after 1 hour. Measurement of body weight was also carried out immediately at birth and weekly during 30 days after birth. Thoracic diameter showed a significant increase between 91-105 days and 121-135 days. Conversely, abdominal diameter had a progressive growth until 106-120 days, and then, a steady development was observed. Biparietal diameter showed progressive growth only towards days 91 and 105. For the humerus length, we verified a significant increase between 106-120 days and 121-135 days, remaining unaltered onwards; while femur length continued to grow until lambing. The linear regression analysis between birth weight and biparietal diameter at 60-75 days was high (R 2 =0.96; P<0.0001; coefficient of variability of 3.3%). In conclusion, ultrasonographic analysis of fetal biparietal diameter at mid-pregnancy can be used as a predictor of lamb weight at birth. Moreover, assessment of femur length at final pregnancy can be employed for fetal and neonatal development estimation.

Assessment of Correlation of Pregnancy Parameters And Fetal Age for Ewes

“…The length of femur in cattle had moderate correlation (R 2 =0.64) with gestation age (Bunyaga, 2017). However, in sheep femur bone continue to grow until lambing, while humerus length significantly increased between 106 and 120 days and remain at same size onward (Vannucchi et al, 2019). Similar observations were recorded in the current study, humerus and forelimb lengths significantly increased in mid gestation and remain unaltered in late stage of pregnancy, whereas tibia and hind limbs, increased in the last gestational group.…”

Assessment of dopperfluxometric indices of maternal-fetal structures in pregnant ewes

“…To predict the vitality of lambs by means of fetal eco-biometry, Vannucchi et al (2019) affirm that there is a relationship between it and lambs' body weight at birth. They also point the importance of biometry to diagnose normal pregnancies.…”

Clinical, ultrasonographic, and postmortem findings in sheep and goats with urinary tract disorders

“…In small ruminants, USG is commonly used at the farm level for gynecological and obstetrical purposes [ 10 ]. USG also has been used to diagnose thoracic [ 11 ], hepatic [ 12 ], and abdominal [ 13 ] afflictions.…”