Ultrasonographic fetal sex identification in pregnant sheep derived from natural mating and embryo transfer.
The objective of this study was to identify the migration period of the genital tubercle and the period of visualization of external genital structures in fetuses of the Dorper breed of sheep derived from natural mating and from fresh, frozen and vitrified embryo transfer. Transrectal ultrasound was performed using a double-frequency linear transducer (6.0 and 8.0 MHz) to monitor 130 ewe fetuses distributed in the four treatments regarding embryo origin. The accuracy of the ultrasound was 100% in this experiment. The fetuses originated from controlled natural mating (NM) and from fresh (FrE), frozen (FE) and vitrified (VE) embryo transfer, with embryos collected 7 days after breeding. Migration of the genital tubercle occurred earlier (P<0.05) in NM (42.21+/-2.86 days) than in FrE (43.98+/-3.00 days), FE (44.97+/-1.83 days) and VE (44.58+/-1.97 days). Visualization of the scrotal bag, prepuce and vulva occurred, respectively, earlier (P<0.05) in NM (45.22+/-1.25, 45.95+/-1.53 and 45.01+/-1.03 days) than in FrE (48.91+/-1.92, 48.52+/-1.41 and 47.41+/-1.41 days), FE (49.97+/-1.08, 49.18+/-2.00 and 47.64+/-1.82 days) and VE (50.12+/-1.66, 49.27+/-1.61 and 47.93+/-1.92 days). The results show that fetal sexing can be accomplished from the 50th day onward in fetuses produced by natural mating and from the 55th day onward in fetuses derived from fresh, frozen and vitrified embryos. It can also be concluded that real-time ultrasonography is a reliable tool for fetal sex determination in sheep taking into account both the location of the genital tubercle and the identification of external genital structures.
Laboratório de Biotécnicas Aplicadas à Reprodução do Departamento de Medicina Veterinária da Universidade Federal Rural de Pernambuco, Brazil.
Leopoldo Mayer
LM
de Freitas Neto
Maico Henrique Barbosa
MH
dos Santos
Cristiano Rocha
CR
de Aguiar Filho
José Monteiro
JM
de Almeida Irmão
Eduardo Luiz Cavalcanti
EL
Caldas
Jairo Pereira
JP
Neves
Paulo Fernandes
PF
Lima
Marcos Antonio Lemos
MA
de Oliveira
D000818:Animals; D019976:Cloning, Organism / Q000379:methods*; D004624:Embryo Transfer / Q000379:methods* / Q000662:veterinary*; D005260:Female; D011247:Pregnancy; D011270:Pregnancy, Animal; D015203:Reproducibility of Results; D027724:Reproductive Techniques, Assisted; D012732:Sex Determination Analysis / Q000379:methods*; D012756:Sheep; D034561:Sheep, Domestic / Q000196:embryology*; D014463:Ultrasonography / Q000379:methods; D016216:Ultrasonography, Prenatal / Q000379:methods* / Q000662:veterinary*