As far as I'm aware Canada will accept a 15 day export certificate.

A Qatar export permit, as a rule, is valid for a maximum of 15 days but come countries require them to be done a maximum of 10 days before departure. The guys at the department don't always know the individual country requirements :)

As a rule of thumb, if you want to do all the running around & paperwork yourself, then an export certificate will cost you QR10.

If you go to a private Pet Relocation company (such as Qatar Pet Relocators) it will cost you QR500 for them to do the paperwork and be on stand by too offer assistance in case there are any problems at the airport (assuming the cat's going accompanied baggage).

If you go to a vet clinic for the paperwork it will cost you QR850+ as they will charge for additional health certificate but as far as I am aware, will not be on stand by if there is a problem, they just arrange the piece of paper.