Aim. The aim of this study was a comparative analysis of karyotypes of purebred, inbred, and crossbred cows of the
Ukrainian red-spotted dairy breed in order to detect their degree of chromosomal aberrations. Methods. The cyto-
genetic study involved 156 cows of the Ukrainian red-spotted dairy breed from two research farms of M.V. Zubets
Institute of Animal Breeding and Genetics, the NAAS. Cultures of peripheral lymphocytes, stimulated with phytohemagglutinin (PHA, Difco, USA) were used according to the method of Moorhead et al. (1960). The chromosomal
preparations were stained with 2 % Giemsa solution (Giemsa, Merk) and analyzed under an Axiostar plus (Carl Zeiss,
Germany) light microscope at 1,000 times magnification. Metaphase slides were photographed with a digital camera
Olympus D-460 ZOOM. The biometric processing of the study results was conducted by ANOVA using Microsoft Excel 2010. Results. Genomic mutations (aneuploidy and polyploidy) and structural aberrations of chromosomes were
found in the karyotypes of the investigated purebred, inbred, and crossbred cows. The total share of aberrant cells varied from 11.4 ± 0.39 % in purebred, 11.8 ± 0.40 % in inbred to 17.30 ± 0.85 % in crossbred cows. In two animals the
Robertson translocation, rob (1 : 29) was found. A statistically significant difference between purebred, inbred, and
crossbred animals was found regarding cells with aneuploidy and structural chromosomal aberrations. Conclusions.
The karyological analysis yielded data showing changes in genetic structure that can have an influence on fertility and
production in different breeding programs.