I have mortality insurance on my horses through Plains Horizon, which also includes $5,000 toward emergency colic surgery. Knock on wood I’ve never had to file a claim but they have been really easy to work with.
As others have said, you will have to disclose your horse’s full medical history. Most likely, they will have an excusion for what she recently went through. Doesnt matter that she was healthy when you bought her. You didn’t insure her then … you are insuring her now.
That is one of the reasons I started insurance on my younger horse when he was only 3. If I keep him insured, he’ll never have an exclusion even if problems develop later, because he has always been insured.