I suspect that the closing of VOOM's U.S. domestic operations will have only a tiny impact for the Canadian channel Treasure HD, and no impact at all for the Canadian channels Rush HD, Equator HD and Oasis HD.
There has never been a VOOM supplied program on Oasis HD, as VOOM is not into nature programming, and as far as I have been able to observe VOOM has only supplied a few programs to Equator HD Canada over the past year or so. For Rush HD, VOOM is keeping its international signal alive, so there should be no impact for Rush HD Canada. For Treasure HD, the programs that were being supplied by VOOM seem to have been replaced by better programs supplied by Smithsonian Channel HD.
Besides, the best stuff on Equator, Rush and Treasure comes from IMAX, not VOOM.