Fetal sexing in small ruminants through visualization of the genital tubercle

Abstract

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.

Early determination of fetal sex in singleton pregnant ewes by real-time polymerase chain reaction and ultrasonography, a comparative study

“…These results were less than those of Amer ( 2010), who recorded 82% accuracy for ewes in pregnancy between 61 and 70 days. Our results were also lower than those of a previous study (Santos et al, 2018), which recorded a reality of 82.61% and 95.83% in ewes at the gestation period of 55 and 65 days, respectively, and they suggested that the false diagnosis, particularly in the male fetuses, maybe due to the delayed migration of genital tubercle occurring later in male fetuses that had been misdiagnosed as females. Their suggestions may elucidate the more significant percentage of false diagnoses in our study regarding the high number of male fetuses compared to that of female fetuses (Table 2), particularly if we know that the male fetuses generally completed their genital tubercles migrate later than those of females, probably due to the increased distance that the genital tubercle must travel in males (Aguiar Filho et al,2010).…”

“…Our ultrasonography results depend on the accurate localization of the genital tubercle (Erdogan, 2012) because it is a hyperechoic structure (Santos et al, 2018). The gestation period of the tested ewes ranged from 50 to 70 days, based on the findings of (Neto et al, 2010), who suggested that fetal sexing is possible in sheep from the 50th day of gestation onward in embryos derived from natural selection mating.…”

“…Their suggestions may elucidate the more significant percentage of false diagnoses in our study regarding the high number of male fetuses compared to that of female fetuses (Table 2), particularly if we know that the male fetuses generally completed their genital tubercles migrate later than those of females, probably due to the increased distance that the genital tubercle must travel in males (Aguiar Filho et al,2010). However, the misdiagnosis of female fetuses as males could be due to structures with similar echogenicity that are mistaken for the genital tubercle, resembling the edges of crumpled hind limbs, or possibly the umbilical cord garbed around the abdomen, as well as the misdiagnosis could frequently happen if diagnoses have been made too early (Santos et al, 2018), as well as the difficulty of manipulating the uterus of sheep and goat during an ultrasonographic investigation, which affected the accuracy of this technique (Santos et al, 2007) and might have been due to differences in the ages and breeds of tested ewes (Asadpour et al, 2015) or due to the fetal status during examination (Ali, 2004). In addition to the differences in the experience of the technician using ultrasonography.…”

Supervisão Da Proteção Radiológica Nos Serviços De Medicina Nuclear No Brasil: Um Panorama Das Regiões Brasileiras

“…A identificação do sexo fetal por ultrassonografia é uma técnica utilizada em animais de alto valor zootécnico. Já foi realizada em cabras e ovelhas (COUBROUGH;CASTELL, 1998;SANTOS et al, 2018) De acordo com a literatura a técnica possui alta confiabilidade nos bovinos, podendo variar de 77% a 95% de acurácia (MÜLLER;WITTKOWSKI, 1986;CURRAN;GINTHER, 1989;KAMIMURA et al, 1994), podendo chegar a 100%, quando realizada entre o 58° ao 68° dia de gestação (CURRAN, 1992 A utilização do Doppler para diagnóstico de gestação pode reduzir o intervalo entre inseminações. Porém, quando se realiza o diagnóstico de gestação por avaliação do fluxo sanguíneo luteal pode ocorrer diagnóstico falso positivo (SIQUEIRA et al, 2013).…”