The objective of the study was to evaluate the uterine histopathological changes in Holstein dairy cows, within the range of 90-145 day in milk, with or without clinical history of reproduction system disorders. Lactating Holstein cows (n =133) with (n=92, 69.17%) or without (n= 41, 30.82%) recorded clinical signs of reproduction diseases were examined for uterine histopathological lesions. The cows in treatment group were inseminated artificially for 3 times after calving or did not have any recorded estrus signs. The cows in control group were not inseminated. Biopsy of the endometrium and submucosa were obtained using a sterile alligator-jawed (rounded) biopsy forceps. The inseminated cows were at various stages of the estrus cycle. The results showed that 64.13% and 46.34% of cows with or without recorded clinical reproductive disorder had histopathological lesions, respectively. There were no significant differences in histopathological changes between cows with or without reproductive disorder history (P≥0.05). Chronic endometritis was the most common microscopic lesion in cows with (34.61%) or without (17.94%) recorded reproductive disease. Clinical endometritis was the most common reproductive disorder (20.65%). The rate of histopathological lesions in repeat breeder cows was16.3%. In conclusion, endometrial biopsy could be a useful diagnostic tool to evaluate future fertility of the dairy cows because, cows with or without reproductive disorders may show histopathological lesions.

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