Absolutely not. I would never breed knowingly having CEA in the line. You can have a litter of eight and one pup carry the CEA gene. Sell that puppy to a person that wants a forever loving pet, They see the development down the road and what does that do to your reputation. its all over the Collie world and everyone talks. Unfortunately show people can be your worst enemy. If they find something out its all over in no time. Like the lady with the bloat in her lines, She has a real hard time selling Show quality dogs now. Now she reverts to lying to potential pet owners about her health line.
There are so many tests that cost so much money to prepare for a female or male to breed. A lot of people are not aware of the preparation and study it takes to breed. I have people in the area wanting to Stud with Steele alot and I hand them the list of priorities and tests that thier Bitch needs to have and tell them I want a copy of all results when they are finished. I never hear back from them for some reason. lol Some say "I never knew you had to test for that on my female, WHY?" They just don't understand what they are doing and think about all the unwanted dogs out there and they want to add to it. On my last litter i had a waiting list of 8 people and had eight pups that survived. 1 person backed out and now I still have one preciuos boy left. He will remain until I find the right person that will properly love him. I have already turned down 5 buyers. I'm pretty paticular on my 4 page application on who gets a Collie I guess. And the puppy? well I just work and train him as he was one of my own that would stay a lifetime. Sorry I got off the subject.
The MDR1 Gene is not as much as a threat if you know your Collie has it. The herding group has seemed to contract this gene more than others here lately. I will admit I have not had all my Collies tested for it but I don't take chances with meds such as Heartworm. I go straight for the Interceptor instead of Intervectim just to be safe. My Smooth Collie has Rabies Vaccinosis and he is never givin a rabies Vac. Instead he gets a yearly Titer Test that costs me $130.
Its kind of crazy how people think lesser of thier dogs as they do humans. We have tests for health reasons why wouldn't we do it for our dogs?