448 RELATION BETWEEN GESTATIONAL AGE AND ULTRASONOGRAPHIC MEASUREMENTS OF CONCEPTUS PARAMETERS IN ANGLO-NUBIAN GOATS RAISED IN THE BRAZILIAN SEMIARID REGION.

The aim of this study was to determine the relation of gestational age with embryonic/fetal measurements in goats through the real-time ultrasound method. Ultrasonographic examinations began on the 25th day after first mating in eight Anglo-Nubian nulliparous goats, using a Falco 100 ultrasound scanner fitted to 6/8 MHz linear-array and 3.5 MHz convex probe. On recorded scanning images, the embryonic vesicle diameter (EVD) and crown-rump length (CRL), head length (HL), bi-parietal diameter (BPD), thoracic diameter (TD), umbilical cord diameter (UCD), long axis of heart (LAH), and short axis of heart (SAH) and placentomes of embryo/fetus were measured using computer software. The relationships between gestational age and each parameter of the ultrasonic measurements were expressed as straight-line equations and plotted as linear regression using Statistica 7.0 software, being statistically significant at a level of P< 0.05. Mean values were correlated to fetal age, and inverse regression equations were created for each parameter. Results obtained showed the following values: EVD (r = 0.94), CRL (r = 0.94), HL (r = 0.74), BPD (r = 0.70), TD (r = 0.88), UCD (r = 0.73), LAH (r = 0.77), SAH (r = 0.80), and placentome (r = 0.71). Additionally, embryonic size increased from the first detection of the embryo to the end of the study. In conclusion, the ultrasonographic technique is a reliable method to estimate gestational age through the embryonic/fetal measurement once its increase follows a linear regression standard. CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico - Brasil). [ABSTRACT FROM AUTHOR]