
Sorry - I've no experience with vaginal prolapses in dogs, but plenty of experience with sheep. In sheep it's reckoned to be a hereditary weakness, and it's recommended that the ewe isn't bred from again (prolapses usually happen around lambing time). I don't think you would want to know the first-aid remedy - and it certainly doesn't involve an anaesthetic!!!

I would guess that in bitches it's caused by the hormonal surge 'loosening everything up' for want of a better term.
I don't think I would risk letting her have another season if she were mine - I'd spay her in about 3 months' time.
Would be interested in other people's views who have bredds which are inclined to do this (don't boxers do it?)
Jo