Fetal sexing in small ruminants through visualization of the genital tubercle

SUMMARY The objective of this study was to verify the accuracy of sexing and fetal number estimation in small ruminants by ultrasonographic examination. Fifty fetuses from 36 sheep and 23 fetuses from 11 goats were evaluated. In the case of sheep, twenty-four, ten, and two pregnancy were single, double, and triple, respectively. Regarding the goats, three, five, two, and one simple pregnancy were single, double, triple, and quadruple, respectively. The evaluations were performed on days 55 and 65 of gestation, by means of transrectal ultrasonographic examination, using a dual-frequency linear transducer, (6.0 and 8.0 MHz). Fetal sex was diagnosed by the location of the genital tubercle or visualization of external genitalia. The accuracy of fetal sexing was evaluated using the Chi-square test (X2) considering a 5% significance level. The gestational period interfered in the accuracy of fetal sexing in both species (P <0.05). Obtained results showed 30% and 82.61% accuracy on day 55 of gestation, and 90% and 95.83% on day 65 for goats and sheep, respectively. The fetal sex and the type of pregnancy did not interfere in the sexing accuracy in both species during the evaluated periods (P> 0.05). Thus, B-mode ultrasonography is an efficient method to perform an early diagnosis of fetal sex and to determine the number of fetuses in the studied small ruminants on day 65 of gestation. In addition, the accuracy of fetal sexing is not influenced by the type of pregnancy or fetal sex.