Year: 2021 | Month: April | Volume 11 | Issue 2

Gestational Age Estimation and Validation using Ultrasonic Measurements of Fetal Biparietal Diameter and Occipito Nasal Length in Nellore Brown Ewes

Kancharla Jyothi Guelal Sudha Kosaraju Mouli Krishna Annayappa Sahadev Muniyappa Narayana Swamy Suguna Rao Manepanda Appaiah Kshama
DOI:10.30954/2277-940X.02.2021.14

Abstract:

Gestational age estimation in small ruminants helps in nutritional management of pregnant ewes and optimizes the lamb survival. Nellore Brown ewes (n = 20) were subjected to short day estrus synchronization protocol and weekly once transabdominal ultrasonography from day 8 onwards until parturition. The biparietal diameter and occipito nasal length of fetal head measured from day 43 until day 113 of gestation. A positive correlation was obtained between gestational age and BPD (r = 0.9687) and ONL (r = 0.9873) and regression equations generated as y = 15.94x + 28.43 and y = 9.471x + 25.66 respectively for BPD and ONL where y is GA and X is respective head measurements. For validation of equations, BPD and ONL were measured in 21 and 12 pregnant ewes respectively, in field test. For linear relationship 61.9 and 71.4% of pregnant ewes delivered within ±7 and ±14 days of expected parturition dates for BPD and 58.3, and 100% of pregnant ewes delivered within ±3 and ±11 days of expected parturition dates for ONL. It was concluded that the ultrasonic measurements of fetal head diameters were well correlated with gestational age and can be used for estimation of pregnancy duration, however, ONL was precise over BPD in predicting parturition dates in Nellore Brown ewes.

Highlights

  • The fetal head diameters were used to estimate and validate gestational age in Nellore ewes
  • The fetal occipito nasal length was proved better in correlation and prediction of lambing dates.


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