Sexagem de fetos caprinos pela ultra-sonografia visualizando as estruturas da genitália externa

Abstract

Two experiments have been performed to evaluate the efficiency of ultrasound to visualization the external genital of fetuses goat. The first study determined the ideal period to sex goat fetuses by the ultrasound in the transrectal way being considered external genital structures. Daily had been monitored, 94 fetuses, being Boer (n = 36), Alpine Brown (n = 31) and Anglo-Nubian (n = 27), from day 40th to 60th of gestation, using linear transducer of 6.0 and 8.0 MHz. The final positioning of the genital tubercle (GT) occurred at day 47.11 ± 1.45 in the males and at day 45.62 ± 1.36 in the females and visualization of the structures of the external genital in the day 49.42 ± 2.20 (scrotum), day 49.37 ± 2.19 (penis), day 49.23 ± 1.75 (nipples) and at day 49.98 ± 2.52 (clitoris). The scrotum, penis, nipples and clitoris had been only visualized, respectively, after days 2.28 ± 2.16, 2.23 ± 2.23, 3.62 ± 1.50 and 4.36 ± 2.27 of the end of the GT migration. The data had shown that the migration of the GT in the female fetus is earlier (P < 0.05) than in the male and that the visualization of the scrotum and the penis is earlier (P < 0.05) than nipples and clitoris, having no difference (P > 0.05) between same sex structures. It was concluded that ultrasound by the transrectal via is an important tool to identify the fetal sex in goat and that is possible to sex fetuses of the studied breeds before 55th day of gestation, considering only the visualization of the external genital structures. The second study the objective was to determine the ideal period to early sex goat fetuses proceeding from simple (SP) and twin (TP) pregnancy. Daily 94 fetuses of Boer (11 SP and 25 TP), Alpine Brown (10 SP and 21 TP) and Anglo-Nubian (8 SP and 19 TP) had been examined, from day 40 to 60 of gestation, to determine the day of the final positioning of the GT and the first visualization day of the scrotum, penis, nipples and clitoris, using a double frequency (6.0 and 8.0 MHz) linear transducer. The final positioning of the GT of male fetuses in the SP occurred in the day 46.83 ± 0.72 and in the females was at day 45.71 ± 1.10, with no difference (P > 0.05) between female and male fetus, as well as between breeds. The visualization of the scrotum occurred in day 49.17 ± 2.41, penis in day 49.25 ± 2.09, nipples in day 49.06 ± 1.78 and the clitoris in day 50.88 ± 3.26, having no difference (P > 0.05) between visualization days. The scrotum, penis, nipples and clitoris had been only visualized, respectively, after days 2.33 ± 2.35, 2.42 ± 2.19, 3.35 ± 1.46 and 5.18 ± 2.81 the migration end of the GT, with no difference (P > 0.05) between scrotum, penis and nipples and between nipples and clitoris, however the clitoris visualization was later (P < 0.05) than scrotum and penis. In TP, the final positioning of the GT of the male fetuses occurred at day 47.13 ± 1.59 and the females at day 45.54 ± 1.45, having difference (P < 0.05) between female and male fetus. The visualization of the scrotum occurred in day 49.43 ± 2.13, penis in day 49.33 ± 2.25, nipples in day 49.21 ± 1.66 and clitoris in 49.36 day ± 1.83, with no difference (P > 0.05) between the visualization days. The scrotum, penis, nipples and clitoris had been only visualized, respectively, after days 2.30 ± 2.15, 2.20 ± 2.25, 3.68 ± 1.54 and 3.82 ± 1.72 in the end of the GT migration, with no difference (P > 0.05)involving scrotum and penis, between nipples and clitoris, although the visualization of the clitoris was more delayed (P < 0.05) than the scrotum and penis. One concludes that the ultrasound by the transrectal via is an efficient to identify the goat fetal sex of the studied breeds before day 55th of gestation, only considering the visualization the external genital structures in simple and twin gestation.