The present study aimed to identify the sex and to determine the day of genital tubercle (GT) migration of ovine fetuses using real time ultrasonography. The sex was identified in Experiment (EI) taking into consideration the localization of GT and in Experiment II (EII) the presence of penis, prepuce and scrotal bag in male fetus and nipples, genital swelling and clitoris in female fetus. In EI, the females (n=17) were monitored with 12 hour intervals from the 35th to the 46th day of pregnancy, by transrectal via with linear transducer (6.0 and 8.0MHz). In EII, the females (n=30) with pregnancy period from 55 to 75 days were examined once only, using the same transducer and via used in EI. Among 17 females in EI, 11 (64.6%) fetuses were correctly sexed independent of single (7/11), twin (3/11) or triple (1/11) pregnancy In 6 (35.4%) pregnancies, 3 (17.7%) were twins, being impossible to sex one fetus of each pregnancy. In other 3 (17.7%) pregnancies the fetuses were correctly sexed, although the birth did not coincide with the quantification. In a male fetus of a single pregnancy, the migration of the GT began on day 37 of pregnancy and on the 46th day all the fetuses of the other pregnancies were correctly sexed. Among 30 females in EII, 16 (53.4%) pregnancies were single being sexed with accuracy of 100%. In other 14 (46.6%) remainder the pregnancies were twins, being impossible, in four cases, to be determined the sex of one of each twin. The incorrect diagnoses were fetuses sexed as females, however born as males. From the all born fetuses the total accuracy was 88.0% (EI) and 90.9% (EII), being not observed difference (P>0.05) between both experiments. The results allow to conclude that ultrasonography in real time is an efficient method to diagnose the fetal sex by visualization of GT, as well as by identification of penis, prepuce and scrotal bag in male fetus and nipples, genital swelling and clitoris in female fetus, since the scanning are performed from Day 50 of pregnancy
genital tubercle; scrotal bag; penis; prepuce; nipples; genital swelling
