A MOSAICISM WITH KARYOTYPE DESIGNATION OF 59X0 60,XX/61,XXX IN RED PIED HEIFER .3./

A Red Pied heifer with a history of anestrus and the diagnosis of gona dal dysgenesis was cytogenetically investigated. The chromosome comple ment was found to be 59. XO/60.XX/61.XXX. Besides the finding of numer ical changes in the karyotype of the investigated animal, a high per c entage of structural chromosomal aberrations was observed too. Based o n these results it can be concluded that the observed mosaicism origin ated from a failure of sister - chromatids of the X chromosome to sepa rate during mitotic division in the early stages of embryogenesis. The finding of structural chromosomal aberrations can not be neglected be cause the investigated heifer arose from an area where pesticides and other agricultural and industrial pollutants were wide used.