Determination of the Genital Tubercle Migration Period in Morada Nova Sheep Foetuses by Ultrasonography

• Published in: Reproduction in domestic animals 2007-04, Vol.42 (2), p.214-217
• Main Authors: Santos, MHB, Rabelo, MC, Guido, SI, Torreão, JNC, Lopes Júnior, ES, Freitas, VJF, De Lima, PF, Oliveira, MAL
• Format: Article
• Language: English
• Subjects: Animal reproduction; Animals; Biological and medical sciences; Breeding of animals; Embryo Transfer - veterinary; Female; Fetuses; Fundamental and applied biological sciences. Psychology; Litter Size; Mammalian reproduction. General aspects; Pregnancy; Sex Determination Analysis - methods; Sex Determination Analysis - veterinary; Sheep; Sheep - embryology; Studies; Time Factors; Ultrasonic imaging; Ultrasonography, Prenatal - methods; Ultrasonography, Prenatal - veterinary; Vertebrates: reproduction
• ISSN: 0936-6768; 1439-0531
• DOI: 10.1111/j.1439-0531.2006.00756.x

Contents The aim of this study was to determine the period of genital tubercle (GT) migration using ultrasonography in Morada Nova sheep foetuses (n = 117) from natural mating (NM) and frozen embryo transfer (ET) to determine the window when foetal sexing can be determined. The examinations were performed using transrectal ultrasonography with a dual‐frequency linear transducer (6.0 and 8.0 MHz) from day 30–54 of pregnancy at 48‐h intervals. The period of GT migration of foetuses produced by NM varied from 36 to 46 days of pregnancy, resulting in an average of 39.5 ± 2.9 days. For foetuses derived from ET, GT migration varied from 42 to 52 days of pregnancy with an average of 48.5 ± 3.3 days, being possible the GT of foetuses from ET start to migrate 96 h later even if they are of the same gender. Migration of the GT occurred earlier (p