Early Prolapsed Vagina.

Early Prolapsed Vagina.
In the early stages of an incipient vaginal prolapse, the hyperemic mass will only present itself in the recumbent cow, and is pulled forward and back inside as she rises. Exposure of the mucosa to the air progressively leads to drying, irritation, swelling, inflammation, pain, straining, causing the prolapsed mass to enlarge so it can no longer go back inside.

Roberts SJ (1973)