Carcase needs to be as fresh as possible but, that said, we took one just hours old straight to the AHVLA last March and were told it wasn't SBV. Over the year, though, we heard quite a few reports of people doing the same thing and, because of the nature of the deformities, we all thought they were SBV but the lab said not (not specified what they test for - antibodies? type of deformity?) Ours was perfect except for no eyeballs in its sockets. Our Hunt kennels had one brought in with no head, just a pair of ears where it should be. But too many deformities in lambing season to be coincidence, surely?