1Department of Veterinary Gynaecology & Obstetrics, College of Veterinary Science, Proddatur, Sri Venkateswara Veterinary University, Andhra Pradesh, India
2Department of Veterinary Gynaecology & Obstetrics, Veterinary College, Hebbal, Bengaluru, Karnataka Veterinary, Animal and Fisheries Sciences University, Karnataka, India
3Department of Veterinary Gynaecology & Obstetrics, College of Veterinary Science, Tirupati, Sri Venkateswara Veterinary University, Andhra Pradesh, India
4Department of Veterinary Physiology, Veterinary College, Hebbal, Bengaluru, Karnataka Veterinary, Animal and Fisheries Sciences University, Karnataka, India
5Department of Veterinary Pathology, Veterinary College, Hebbal, Bengaluru, Karnataka Veterinary, Animal and Fisheries Sciences University, Karnataka, India
6Department of Veterinary Clinical Complex, Veterinary College, Hebbal, Bengaluru, Karnataka Veterinary, Animal and Fisheries Sciences University, Karnataka, India
*Corresponding author: K Jyothi; E-mail: jyothik100@gmail.com
Online Published on 21 September, 2022.
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.
• 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.
Estrus Synchronization, Transabdominal ultrasonography, Correlation, Regression equation
