Hydrops Allantois.

Hydrops Allantois.
This ewe is down in sternal recumbency due to the excessive weight of allantoic fluid, a result of hydrallantois. The etiology of hydrops allantois is adventitious placentation. This condition is typically seen during the last third of gestation and may lead to severe respiratory distress due to pressure on the diaphragm.

Utrecht (1976)