Ovarian follicular cysts occur in up to 25 percent of dairy cows during the first 6 to 7 weeks postpartum. Approximately 20 to 50 percent of the follicular cysts will regress spontaneously and treatment usually is delayed until after the 8th week postpartum. By this time, one or more breeding periods may be missed and extended calving intervals can occur. Generally, higher milk production is associated with ovarian cysts. Whether high milk production causes ovarian cysts or ovarian cysts cause higher milk production is not clear, but hormonal balance rather than nutrition appears to be the cause.
Few reports link cystic ovaries and nutrition.
High levels of grain feeding have been associated with increased frequencies of cystic follicles. Anestrus rather than nymphomania was the primary behavioral sign associated with the cystic follicles. Abortions and cystic ovaries have been prevalent on farms feeding relatively high manganese feeds while anestrus occurred on farms feeding low manganese. Plant estrogens and beta-carotene deficiencies have also been linked to cystic follicles. Embryonic Death and Abortions.