Can you enter a AKC registered dog in CKC events? YES!
To receive its Canadian Championship it must have an ERN or CKC number. You will not need either prior to enterinng a show. Without your ERN or CKC number your dog will be entered as "Listed".
EVENT REGISTRATION FEE
Effective Jan. 1/92, all dogs that are foreign born and foreign owned and enter Canada for the sole purpose of entering CKC events will no longer require a CKC registration number but will require an Event Registration Number (ERN).
The ERN number MUST be applied for within 30 days of the first day of entering a CKC event.
Fee is $59.40 per dog after January 19, 2015 plus applicable taxes. For further information contact:
The Canadian Kennel Club Phone: (416) 675-5511 Fax: (416) 675-6506 information@ckc.ca Hours: 9:00 a.m. - 5:00 p.m. (Monday - Friday)

You do need a valid rabies certificate
to cross the border going both ways.