There are also white catahoulas that are not double mearl or single mearled dog i have one from johnny wager and ( he breeds this line with no def or blind pups) snoopy that is my dogs name now he is starting to show black spots on his body but for the most part he is solid white his daddy is solid white no black on his body and he (snoopy) came from a white daddy and a solid black momma.
If Snoopy came from a white daddy, the daddy was double merle. If Snoopy came from a solid black momma, the momma was
non merle. This breeding should produce single merle pups with no issues.