41 heifers of 260-440 kg body weight used in an experiment were polyovulated with PGF2 alpha and PMSG (1000 IU). Animals were slaughtered during luteal phase of ovarian cycle (day 12-15). Shortly before slaughter ovarian structures were defined by rectal palpation und ultrasonographical examination. Post mortem ovaries were collected to compare their structures with previously performed in vivo diagnosis. More follicular structures were detected sonographically (109%) than could be found by morphologic examination (100%). Concerning corpora lutea a right diagnosis was made by palpation in 94% of cases, whereas the rate was only 85% for ultrasonographical examination. Main reasons for false diagnoses of ultrasonographical examination are as follows: multiple ovarian structures, corpora lutea with holes inside, atypical shape of ovaries, atypical ultrasonographical pictures and irregular shape of follicles.