Displacement of the tubular genital tract of the ewe during pregnancy

The displacement of the tubular genital tract of ewes during pregnancy, in particular of the cervix relative to the cranial pelvic brim, was studied by sequential radiography using radio-opaque markers attached surgically before tupping. In the first year, 13 two-year-old parous ewes were fed a complete pelleted diet containing either 15 or 25 per cent fibre throughout pregnancy. The distances between the markers attached to the tubulogenital tract increased and the distance between the cervix and the cranial pelvic brim increased slightly with advancing pregnancy; the diet had no effect. In the second year, only cervical displacement was studied in 11 ewes that had suffered a cervicovaginal prolapse the previous year, and in five of their female progeny. They were divided into two groups, one of which was fed a 15 per cent-fibre complete pelleted diet and the other hay ad libitum throughout pregnancy. In two ewes, one from each dietary group, the prolapse recurred less than two weeks from term; initially it was a stage 2 prolapse, where the vaginal wall fails to return to its normal position when the ewe stands, but in one ewe it became a stage 3 prolapse, with the vagina completely everted and the cervix visible. During the stage 2 prolapse there was no evidence of caudal displacement of the cervix, whereas during the progression to the stage 3 prolapse the cervix became displaced 33 cm caudally over two to three hours.