Hi,
I saw the photo of lucy in your gallery. I would say it has ascites and liver enlargement (hepatomegaly). There seems to be specific fluid accumulation in the abdominal region. Unlike generalised oedema (bloat), this is less likely to be caused by an infection but rather a liver or kidney problem.
The cause of this could be genetic, dietary related or certain toxins. There has been some papers that suggest virus infections could also cause this.
Treatment wise, fridging is a must. Veterinary intervention is also a must. The axie could have the excess fluid accumulation aspirated out via a needle. Extensive fluid therapy will help it substantially as well. If the cause is of a genetic nature, i would advise on euthanasia because it would be an ongoing, incurable condition.