Purebred dog breeders are at a loss after the enforcement of the rules for sending puppies to the United States changed without notice.

The Centers for Disease Control and Protection (CDC) requires puppies entering the U.S. receive the rabies vaccination when they are only three months old. Following their shots, the dogs must undergo a 30 day waiting period before they can cross the border. The policy has been in place since the 1950s.

While the rules have not changed, border enforcement of the rules has. Prior to this week, breeders would typically send Canadian puppies home with their new American families when the dogs were only two months old.

Joan Grainger has bred purebred flat coated retrievers since the mid-1980s. Her most recent litter arrived earlier this summer and the nine dogs are now six weeks old.

Grainger had secured U.S. buyers for four of the dogs, but the new CDC policy means the puppy-owner introductions will be postponed. The delay has prompted two of the buyers to back out of their agreements.

“If we start to eliminate the ability to import or export dogs, it's going to have a huge impact on the breeds, not just on mine, but all breeds,” said Grainger.

The dog breeder says flat coated retrievers require specific training within their first two months.

“You have to start your hunt training at seven weeks. You have to start your obedience training at seven to eight weeks of age to make them good working and obedience dogs.”

Grainger says the enforcement of the rules delays the training of the dogs during a formative period of their development and leaves the breeder facing an additional month of expenses.

Canadian breeders, including Grainger, are writing to the CDC to find out why the policy has changed, but they're not getting far.

“The response that I got from (the CDC) says ‘We’re sorry that we haven’t answered your questions’,” said Grainger. “They didn’t ask me what my questions were, but they’re sorry that they didn’t answer them.”

For more information on the CDC’s dog importation policy, visit:

With files from CTV's Kevin Fleming