Bay got kicked once, we think.... and ended up with a big soft Edema on his side, it looked like a melon under the skin.... vet came out and looked at it and said the bubble of fluid would probably gravitate under his belly, which it did, and be slowly reabsorbed, which took a long time. It probably looked a lot like your tire, which is why I asked yesterday if it felt soft, like it was just full of fluid. Any discussion or memory about whether she might have suffered some kind of blow to the gut? Or is there some internal cause of edemas that doesn't have to do with a blunt trauma?
The vet said she was just retaining fluid because she is not getting much exercise due to her bulk. The edema is the length of her belly and about 3 inches thick, thats why it looks like a tire! It is also symetrical.
Sugar is not herself at all today, very edgy and testy.
I am glad that the vet has been but I wont stop worrying till the foal has been born. I just went on a site that said that a low lying edema in late pregnancy may be the result of an extra large foal or a foal in the wrong position. So to say the least I am still concerned.