I have had several vaginal prolapses. The vast majority of them are before they calve. They are cows that I have bought I always figure that was why they were sold. Do you know what kind of string the vet used to sew her up? There is the kind that is like shoe string and will not break and there is the kind that is like cat gut and will break when she pushes hard enough.
Normally, if the cow has not freshened, I use the cat gut so that when the calf enters the birth canal, it will break and she will have the calf. There is the chance it will break before she freshens, if that happens, do it again and use the tough string. You can either cut it when the calf enters the birth canal, or you can go ahead and sell her and not have the worry.
If the cow has already freshened, I use the kind that cant break, let her get in good shape while raising the calf and then sell her for slaughter and the calf as a feeder.
It is normal for the cow to swell behind after being stitched up and she will stay swelled for a period of time that can last weeks, but will usually be less.
After you have watched the vet do it, it is easy for you to keep a needle on hand and do it yourself and save the vet bill. You can have the cat gut and tough string or some people just use baler twine and I know a couple of guys who have used baling wire.
Except for one, I have sold every cow that prolapsed for slaughter. I am told it will happen again every time. I had one 3 year old cow that prolapsed after calving, sewed her up and forgot to sell her, she made it fine the next time and raised over 10 more calves and was sold for slaughter as an old cow.
The problem is these guys who sell a prolapsed cow back into the farms. They should all be sold for slaughter.