Histological examination of ovaries and uteri from cows with cystic ovaries.

Sections were cut from 486 cysts taken from 260 pairs of cystic ovaries which had been collected during an abattoir survey. The linine of the cysts was examined for the presence of granulosa, basement membrane, theca and luteinisation. Sections of the uteri were examined and the nature of the surface epithelium, the thickness of the endometrium and the activity of the uterine glands were recorded. In those cysts associated with a corpus luteum both granulosa and luteinisation were seen less often than in other cysts. Of the 486 cysts examined 111 (22-84 per cent) had luteinisation, the others had none. Luteinisation was most often encountered when granulosa was absent. The thickness of theca was greater in cysts than in normal follicles and was thickest in thick walled cysts associated with a corpus luteum. The majority of uteri (81-9 per cent) were normal and only in 4-78 per cent was "swiss chese" dilation of the glands seen. Thirteen cases of mucometra were seen and these are discussed in detail.