Sisaèko-moslavaèka County, Department of Agriculture, Sisak, Croatia
A syndrome associated with conditions leading to anovular follicles or to cystic ovaries is that of ovulation failure. Condition is obviously multicausal, with some findings supporting the theory that is hereditary, and affected by the season of the year. However, most evidence is consistent with the lack of an LH surge being the critical underlying physiological change that leads to anovulatory condition. Diagnosis of anovulation can only be made retrospectively, by noting that a follicle persists longer than expected. It was reported that cows can spontaneously recover from ovulatory failure by mechanisms that still remain unclear. Improvement in energy status can reduce the period of anovulation. In the various hormonal treatments responses are not uniform, since they appear to be dependent on factors influencing the prevalence of ovulation failure. Therefore, no particular treatment can be recommended unequivocally for all cows. On the other hand, it seems that anovular cows can be successfuly synchronized and time inseminated using the protocols combining progesterone, GnRH and prostaglandin analogues.
Cow, cyst, ovary, ovulation
