Determination of Fetal Gender by Transrectal Ultrasound Examination: Field’s Experience

Fetal determination has been conducted for almost 20 yr. In 1989, Curran and Ginther first identified fetal gender by evaluating the location of the genital tubercle in the male and female fetus using transrectal examination between 54 and 84 days of gestation. More recently, others 4 have described fetal-gender determination in midand late pregnancy using a transabdominal technique. Knowing fetal gender has economic importance. Fetal gender is used to determine which mares are to be taken to sales and what stallions are booked the following season, because stud fees and sales revenues differ according to the foal’s gender. Male foals or yearlings frequently sell for more money than females. It is also possible to adjust insurance fees of pregnant mares according to fetal gender. The aim of the present work is to show that transrectal determination of fetal gender between 55 and 75 and 90 and 150 days of gestation can be accomplished in a timely manner in routine stud practice if the veterinarian is experienced in reproductive ultrasonography. 2. Materials and Methods