STUDIES ON ULTRASONOGRAPHIC FETOMETRY TO DETERMINE GESTATIONAL AGE IN NELLORE EWES AND ITS VALIDATION IN THE FIELD
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Date
2021-02-01
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KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, BIDAR
Abstract
The present investigation was carried out by using 20 synchronized pregnant
Nellore Brown ewes and documented normal intrauterine development of fetus using
transabdominal ultrasonography. The EVD, CRL, BPD, ONL and PL were measured
between days 22-64; 29-64: 43-113; 43-113 and 43-141 during gestation respectively and
obtained high significant correlation (p<0.05) between GA and EVD (r= 0.9497; R2 =
0.902), CRL (r=0.9573; R2 = 0.916), BPD (r=0.9687; R2 = 0.938), ONL (r = 0.9873; R2
= 0.974) and moderate correlation for PL (r = 0.6850; R2 =0.470) between days 43 - 78 of
gestation. The regression equations, y = 5.319x + 18.09; y = 3.808x + 27.23; y = 15.94x
+ 28.43; y = 9.471x + 25.66; y = 11.87x + 34.13 were computed between GA and EVD,
CRL, BPD, ONL and PL (up to 78 days), respectively where y is gestational age in days
and x is the ultrasonic parameter in centimetres. The regression equations generated were
validated in the field, 30 and 100 per cent of ewes delivered within ± 7 and ± 14 days of
expected parturition dates for EVD, 55.5 and 100 per cent of ewes delivered within ± 7
and ± 12 days for CRL, 61.9 and 71.4 per cent of ewes delivered within ± 7 and ± 14
days for BPD, 58.3, and 100 per cent of ewes delivered within ± 3 and ± 11 days for
ONL and for placentome length 62 and 100 per cent of ewes, in first half of gestation,
delivered within ±7 and ±14 days of expected parturition dates, respectively. It could be
concluded that the fetal parameters studied in the present study were well correlated and
validated with gestational age except the placentome length. Further research is required
to define the significance of equations in the field conditions.