Cytological examination of calves with congenital defects and heterosexual twins

Cytological examinations were executed on the 23 calves with congenital defects as well as on the 10 pairs of the heterosexual twin calves. The above mentioned congenital defects were sorted out as in the following: arthrogryposis, hydranencephaly, internal hydrocephalus, cerebellar hypoplasia, cleft palate, dermoid, atresia ani, Fallot-tetralogy, left hind limb-amelia, weak ones and so on. The karyotypes of these 20 calves with congenital defects showed either 60XX or 6XY cells, being normal cytologically. As shown in the following, chromosome abnormalities were detected in 3 calves. Case 1 was occassioned in a male Japanese black beef breed calf showing severe brachygnathism, in other organs no defects were detected morphologically. Cytologically this was fixed to be a chromosome mosaic of 60XY/59XY, which was somewhat different from trisomy reported in several brachygnatia calves. Case 2 was occassioned in a male Japanese black calf showing slight prognathism, in other organs no defects were detected morphologically. Cytologically this was fixed to be a sort of autosomal trisomy. This calf was delivered by a dam of 15 years old at her 12th parturition. Accordingly, the cause of this trisomy was reasonably assumed to have been induced by a chromosomal dysseparation of oocytes brought forth by ovarian senescence. Case 3 was occassioned in a female Holstein calf with small vulva as well as with quite shortened prove-insertion, counting only 1 cm, respectively. By the pathological examinations of vaginal stricture, vaginal cyst and ovarian hypoplasia were detected too. And this was fixed to be a single freemartin. Through the examinations of 10 pairs of the heterosexual twin calves the external genital organs were recognized to be quite normal in all the male calves