CYSTIC DEGENERATION IN PORCINE OVARIES .1. MORPHOLOGY OF CYSTIC OVARIES, INTERPRETATION OF THE RESULTS

The morphological appearance of ovarian structures in 79 sows with ova rian cysts was examined. Sixty sows had been culled due to sterility; 19 sows had been repeatedly investigated clinically before slaughter. It was found that cystic ovaries without corpora lutea (CL) had the la rgest diameter and volume (151.3 cm3), in comparison to both cystic ov aries with CL (85.7 cm3) and normalovaries (16.9 cm3). The number of c ysts on ovaries without corpora lutea was approximately twice as high as on the ovaries with CL (23.3 vs 12.1 cysts/sow; p < 0.001). A combi ned form of degeneration consisting of large (> 1.5 cm in diameter) an d small (less-than-or-equal-to 1.5 cm in diameter) cysts was found in 63% of the animals, whereas degeneration with only small cysts occured in 8% of the cases. Dark CL, interpreted as being functional, were ma inly present in animals with up to 10 cysts per sow (24 out of 27 sows , p < 0.001); pale CL, interpreted as being weakly functional, were ma inly found on ovaries with more than 10 cysts (19 out of 23 sows; p < 0.001). Based on macroscopical differentiation cyclic activity was fou nd to be dependent to the number of cysts. Regular or irregular estrou s cycles were observed in oligocystic animals (less-than-or-equal-to 1 0 cysts/animal) with functional CL (58%). Up to 75% of the animals wit h pale or absent CL showed no estrous activity.