I'm going to Washington via Oregon this summer in July from California. I was reading up on any entry requirements I might need for my horses. Most of it is your standard coggins and health cert but Oregon is listing an " Import certificate" . Any idea on what that might be? Thanks!
Unless you're stopping in Oregon and staying for an extended time (longer than getting gas, etc.), you don't have to do anything special as far as import requirements go.
If WA is your final destination, then you would need an entry permit number on your health papers (which your veterinarian's office will get for you). Legally to enter the state of WA, you will need a brand inspection, which is just a proof of ownership. Not many brand inspectors will stop and ask you for your paperwork, but it's always good to be prepared.