Foetal anasarca (hydrops foetalis) in an 8 month gestation male bovine foetus. The carcase showed a huge amount of sub cutaneous oedema with pockets full with fluid. Internally the gall bladder was hugely distended but the other internal organs as well as the brain appeared normal. There was no other case in the herd. Hydrops foetalis is defined as a state of excessive fluid accumulation in the extravascular compartment of the foetus, leading to widespread soft tissue oedema and/or accumulation of fluid in the foetal body cavities. A search in the literature relates the condition in some cases to circulatory malfunction and others to a recessive gene. A case was reported where it was present with pulmonary agenesis.
When submitting blood samples for testing please give age & history of the animals as the tests we do are based on the case. The following gives an indication on what tests we do in different situations. BVD antigen Elisa is carried out on bloods from animals with suspect clinical signs. BVD antigen Elisa is carried out on calves 3-6 months old. (maternal antibodies persist for around 6 months and it is pointless doing antibody tests on animals <6 months old. BVD PCR is carried out on calves <3 months old. (the level of maternal antibodies can mask the virus at this age and prevent the Elisa test detecting it.). BVD antibody Elisa is the preferred test for weanlings 9-12 months old with a view to establishing if virus has been circulating in the herd in the recent past. (serum samples from six weanlings 9-12 months is preferred) A bulk tank sample ( around 50 ml) from a dairy herd taken when the majority of the herd are milking, tested for antigen gives information if there is a persistently infected animals among the cows.
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