Ovarian Cyst and its Economic Impact in Dairy Farms: A Review

Abstract

Ovarian cyst is one of the major causes of reproductive failure and economic loss in the dairy industry. The objectives of this paper were to give general overview about cystic ovarian disease and its economic impact in dairy cattle. By rectal palpation, ovarian cysts are characterized as structures greater than minimum diameter of 17mm persisting for more than 6 days. Major categories of cysts include follicular cysts, luteinized follicular cysts and cystic corpora lutea. Follicular cysts result from failure of ovulation and luteinization. Luteinized cysts apparently fail to ovulate, but some luteinization occurs. Because of the varying degree of luteinization, luteinized cysts are firmer to touch than follicular cysts though not as solid as corpus luteum. Cystic corpora lutea are corpus luteum with a fluid filled center. Various risk factors related to development of ovarian cysts in individual cows have been identified, although the actual cause of cystic ovarian disease is unknown. The basic pathophysiology of cystic ovarian disease involves a neuroendocrine dysfunction of the hypothalamic-pituitary-ovarian axis resulting in ovulation failure. An abnormal pattern of estrous behavior is the most noticeable sign of cystic ovarian disease. A cow with an ovarian cyst might exhibit “constant” estrus (nymphomania), no estrus (anestrus) or anerratic combination of estrus and anestrus. Accurate diagnosis currently employs a combination of transrectal palpation, transrectal ultrasonography and plasma progesterone assay. During earlier times, the manual rupture of ovarian cysts was advocated, yet during the past several years single or combinations human chorionic Gonadotrophin, Gonadotrophin releasing hormone, progesterone and prostaglandins have been frequent in clinical practice. The success of therapy is governed by many confounding variables such as persistence of the cystic follicles and initiation of therapy as pathological alterations that occur following ovarian cysts persistence require some time for spontaneous recovery. Generally all of these risk factors should be thoroughly considered and based on the knowledge of their existence, measures should be taken to prevent increased incidence of ovarian cysts COD.