Sex Determination of Bovine Embryos Using H-Y Antibodies

Abstract

6 days old bovine embryos (n = 126) were obtained from 8 superovulated cows or heifers by flushing the uteri and oviducts either non-surgially or after slaughter. Part of the embryos (n = 72) (morula stages) were placed in Ham’s F-10 or PBS supplemented with 10% fetal calf serum (FCS) diluted 1:1 with supernatant from the H-Y antibody producing clone and cultured at 38°C, in 5 % CO2/95 % air and 100 % humidity. Control embryos (n = 54) were cultured in H-Y antibody free medium. After culture the embryos could be separated into a blastocyst- and a morula group. A subsequent colchemid and hypotonic treatment and fixation and Giemsa staining allowed a precise karyotyping, and thus sex determination for 36 H-Y antibody treated embryos and 22 control embryos. The limiting factor for proper karyotyping was lack of metaphases, incomplete methaphases or poor preparation. Among the H-Y antibody treated embryos we found 7 males and 15 females in the blastocyst and 14 males and 0 females in the morula group. A statistical analysis of these proportions led to the conclusion that the H-Y antibody had a significant influence on the sex ratio.