engleski

Cistic ovarian follicles

Reproduction is one of the key targets in dairy production. Reproductive disorders including cystic ovarian follicles (COF) present a great problem in dairy cow's management. COF in cows and heifers traditionally have been define as an anovulatory fluid-filled hollow structures having diameter ≥ 2.5 cm that persist for 10 or more days in the absence or in presence of a corpus luteum which persist in one or both ovaries and accompanied by abnormal oestrus behavior. COF are considered to be one of the most frequent and important causes of ovarian disorders and reproductive failure in modern high yielding dairy cows. COF etiology is very complex. There is no single cause of COF, an interaction between hereditary predisposition, milk yield, age, season, nutrition management, stress and negative energy balance is important in COF development. Negative energy balance are thougt to be one of the most imortant factors contributing to the formation of COF during early puerperium. COF could be single and multiple, follicular and luteal. Clinical signs of COF depend on the extent of luteinisation of the cyst, in most cases cows with COF are anoestrus. Rectal palpation, ultrasonography and determination of progesterone concentrations in plasma or milk are common diagnostic tools for COF. By careful genetic selection, improvements have been by elimitating bulls that have sired daughters subsequently suffering from COF. Prevention of COF can be approched by identifying and eliminating the contibutory causes of disorder and prophylactic use of GnRH 12-14 days after calving. By using the most recent treatment methods it is possible to cure numerous affected cows. The choice of the treatment and success will depend on some extent upon the cyst type. It can be used GnRH, hCG alone or in combination with progestagens, progestagens and PGF2α for treatment of luteal cyst. Maybe the most efficency treatment is the use of GnRH and PGF2α 9-11 days post treatment with GnRH no matter of cysts type. Clear understanding of COF etiology, pathogenesis and prevention contribute to better approach to reproductive management of dairy cows avoiding it's incidency as much as possible.

cistic ovarian follicles; dairy cows; reproduction

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