Abstract

The present study was conducted to characterize early embryonic developmental features in North-Western Himalayan Gaddi sheep (n=15) using B-Mode transrectal ultrasonography at Livestock Farm Complex, CSKHPKV, Palampur, India (32.6° N, 76.3° E, altitude of 1290.8 m). Transrectal ultrasonographic examinations (TRUS) were conducted sequentially at weekly interval between Day 14-35 using portable ultrasound machine (IMAGO® ECM, IMV imaging) equipped with linear rectal transducer of variable frequency (5.0-7.5 MHz) to study embryonic biometry parameters, accuracy, sensitivity, specificity, positive and negative predictive value along with their precision. Significant increase (p< 0.05) in embryonic biometry was observed from Day 14-35. Precision of early embryonic features increases significantly (p<0.01) beyond Day 21 in majority of structures (except embryonic sac; Day 14 onwards) with Day 28 as best time for evaluation of pregnancy diagnosis in Gaddi sheep. All the embryonic biometry parameters were positively correlated (p<0.01) with each other. Various predictive equations were also formulated by exploiting the embryonic biometry parameters for predicting gestation age. Body diameter was most reliable parameter for estimation of gestation age with highest determinant coefficient (R2, 97.6) followed by embryonic sac diameter (R2, 95.9) for Gaddi ewes, respectively. In conclusion, TRUS was most convenient at Day 28 post mating with better accuracy, higher sensitivity, specificity and increased proportion of Gaddi ewes having positive and negative predictive values.

Keywords

Ultrasonographic; Sheep; Gestation