Bilateral polycystic ovary in a nellore cow: case report

The most common ovarian disease in cattle is follicular cyst, but there are few studies addressing this problem in zebuid cows on pasture. In humans, this condition is known as polycystic ovary syndrome (PCOS). The aim of this study is to report on the occurrence of polycystic ovary syndrome in a multivariate Nellore cow kept on pasture. The case was detected during an ultrasound examination of the reproductive tract at the beginning of the breeding season. The cow in question was approximately 60 days postpartum and rectal palpation revealed bilateral ovarian enlargement. Ultrasound examination revealed a low-echo lobular image suggestive of multiple follicles. Without treatment, the cow was slaughtered and her reproductive tract removed for macroscopic, morphometric and histopathologic analysis. The ovaries were found to contain a large number of cystic formations of varying sizes, confirming the diagnosis of polycystic ovary syndrome. Although PCOS is well documented in humans, it has not yet been described in female cattle. This report is novel in that cows kept on pasture and fed only mineral salt rarely show ovarian pathologies. It can therefore serve as a guide for professionals in the field who are aware of the possible occurrence of this case.