Merle Rat Terriers are a hybrid breed. They are a cross of Chihuahua and Rat Terrier. Further more-- Chihuahua’s are not even part of the Rat Terrier breed history. Chihuahua was not even attempted to be introduced into Rat Terriers until the late 1980’s and yes, merle was most likely crossed in then.
NONE of the reputable registries even allow this color pattern. If your breed has a history of merle, then by all measns you should take a risk with the pattern, but if your breed does not, like Rat Terriers then this should be avoided. Merle has very well known health issues. Most thought if you stay away from breeding merle to merle it would be fine. In 2005 a documented study prooves this is not true. A puppy from 2 non-merle parents has a less chance of getting health issue related to this patter than a puppy with a single merle parent. NOT double merel SINGLE merle.
Breeders should always breed for the betterment of the breed. There is not 1 good reason for merle to be introduced, but there are a LOT of bad reason why we should not. And if this is not even suppose to be part of the breed… Then WHY?
Even UKCI (Uninted Kennels Club International) says it is a disqualification yet they register them ???
Here are a few link to back me up…>
The 2005 study proving single merle puppies having a greater health risk http://www.lsu.edu/deafness/ClarkPNASMerle.pdf
The in depth article about why merle is bad and why it is not part of a Rat Terrier.
http://photos.imageevent.com/kndkennels/thekndvoice/merle/merle.doc
I welcome any talks on this topic. If you have proof that merle is totally safe and is part of a TRUE PUREBRED Rat Terrier… I would love to read it.
I love this breed and I fight for it… and many many many people want to sweep this documented study under the carpet. They wish it was a lie but it ain’t going away.