@imagebeastmarkbeast With a proper breeding program, you wouldn’t be crossing two animals who have similar issues in their backgrounds. For example, you have female poodle with a Zz gene. Big Z being healthy heart and little z being a predisposition for cardiomyopathy. You would look for a male poodle of ZZ origins ideally. If you cross a Zz with Zz, you have a 25% chance of pups with cardiomyopathy, a 50% chance of the pups as carriers of the gene, and a 25% chance with clear and healthy hearts. In an ideal breeding program, you would retire the bitch because she is a carrier and find a bitch with ZZ. Now that’s an oversimplification of it because there isn’t a single gene that predicts all the possible issues and just because it affects one gene, doesn’t mean it doesn’t mean it causes an interaction with another phenotype. The problem with breeds being prone to issues is that there are unethical or sloppy breeders who don’t care if they mix a Zz with a zz or Zz.
This is why doodles often express the worst of both breeds because they will take a bitch or a stud simply because it has papers as a poodle or a golden retriever or whatever the hell else they want the poodle to doodle. So you might get a poodle who is prone to allergies and cancer and a golden retriever who is prone to both too. Instead of looking into the background of the animal, too often we are seeing pups who were bred for the sake of money, not health. Because there are cross overs between problems with breeds (allergies being a big one right now), they are being expressed with a lot of the doodles, thus negating any “hybrid vigor” theory.
