1. Department of Genetics and Reproduction; Veterinary Research Institute; Brno Czech Republic
2. Department of Animal Breeding; Faculty of Agronomy; Mendel University in Brno; Brno Czech Republic
3. Department of Histology and Embryology; Department of Anatomy; Poznan University of Medical Science; Poznan Poland
4. Institute of Veterinary Sciences; Poznan University of Life Sciences; Poznan Poland