Evaluating sows with reproductive problems, Meredith (1977) found six cases of cysts
in 46 animals (13%) by rectal palpation. Likewise, Heinonen et al. (1998) by evaluating
tissues obtained from the slaughterhouse found that 6.2% of sows with reproductive failure
had ovarian cysts. In non-pregnant sows, Gherpelli and Tarocco (1996) found 3.3% of cases
associated with the presence of ovarian cysts. The described cyst incidences are based on the
examination of a population where some previous reproductive problems had been found
which led to reproductive failure and culling of sows. With the use of ultrasonography
to evaluate the pre-weaning pattern of ovarian follicular development, Lucy et al. (1999)
describes that a small percentage of sows have a pre-weaning cystic ovary and do not show
signs of estrus after weaning. However, in the present study, all animals examined had
shown estrus and did not have any record of previous reproductive failures, which may
explain the low cyst incidence that was detected.