Maybe it's worth pointing out what CFIA does at the airport.
In this case, the CFIA at the airport ensures that animals are healthy, are fit to travel are not overcrowded and are compatible. We do a visual inspection to verify the horses can stand comfortably naturally and that they don't come into contact with their container cover when they're standing naturally. CFIA inspectors are present when the horses are loaded.
When I say that we ensure animals are compatible, we consider things like their size, making sure there is a relative uniformity in their size in a particular enclosure so that you don't have one very large animal and one very small animal, for example, which would cause issues during transport.
I think it's worth pointing out that CFIA inspectors and veterinarians are at the airport when the animals are off-loaded from the trucks, put into the containers and put onto a plane, to make sure they are fit to travel, are healthy, are not overcrowded and are compatible.