Ashleygrove Gundogs

Having had one of my Labs tested for this I was pleased to recieve this info on how to proceed and what the illness means.

Breeding Carriers to Certified Clean Labradors:

There have been many excellent Labradors that have been carriers --- in the past and currently. We recommend that those very high quality dogs are not immediately eliminated from the gene pool. To do so would cause the possible loss of many excellent characteristics that are desirable in Labradors as well as narrow the already small gene pool.

Carrier Labradors might be bred to tested CNM clean where there is a known interest in having a pup by the carrier to clean breeding and when the pups would have many other excellent characteristics that would contribute very positively to the genetic pool.

Placing the well bred carrier pups is often not a great difficulty. Many people do not want to ever breed their Labradors and it makes no difference to them what the pup genetically carries. A carrier never has any physically characteristics of the disease; and therefore many owners would be very happy in owning a well bred carrier.

An important point however is that the purchasers of carrier or potential carrier pups, be fully informed so that they do not mistakenly breed a carrier to carrier that would result in a litter with CNM affected pups. Full and open communication is the most ethical position for breeders to consider.

A CNM carrier bred to a clean Labrador will statistically produce 50% clean and 50% carriers. This means it is the average of what will be produced. Each individual litter will vary.

When breeding a carrier to clean litter and marketing the pups, the breeder has choices:

• Tell the puppy adopters that there is a 50% possibility and that they should test their pup before breeding

• Test the litter and tell the puppy adopters whether their pup is a carrier or clean and give that information to the purchaser. See the section on Testing a Litter.

The puppy adopter who has a carrier could make the same decisions for future breeding that the original breeder made. Those Labradors bred should have characteristics that should be passed on. They would be bred with care to avoid having affected litters.

Using very careful decision making, with full disclosure regarding carriers; the Labrador gene pool would not be diminished, but the CNM mutation would be slowly eliminated in several generations.

Midge tested as a carrier for this desease so I asked the laboratory for further advice. (The link to You Tube shows a graphic video which is not for the faint hearted.)

I looked at what you sent me and see that Midge is a carrier. If you do breed her, we suggest testing the litter or at least fully informing buyers that about 50% of the pups might be carriers. I attached information for you on testing litters

There is no way to get a carrier pup unless one of the two parents are carriers. Obviously one of Midge’s parents is a carrier. I hope that you can tell the breeder this so they warn other buyers out of the dog that is a carrier. They might not even be aware of the disease. If mistakenly two carriers are bred, you get a pup like this

http://www.youtube.com/watch?v=RY1DWQqoac0

If the breeder of Midge contacts all of Midge’s siblings and tells them to test before breeding, it would be helpful for the Labrador gene pool in the UK.

We realize that the CNM test is new to the UK --- as compared to some other countries. Many still do not know that it exists and many people do not realize that carriers do not show symptoms. We have recently tested several affected CNM pups in the UK. Therefore it is clear that many breeders have no idea that CNM exists or how to test for it. Some of the parents of the affected pups are said to be very popular successful Labradors in the UK..

In the UK, it is around 20% of the Labradors we have tested that are carriers or affected CNM.

Let me know if I can answer any more questions.

Kind regards,

Marilyn

Marilyn J Fender, PhD

cnminfo@centurytel.net

Global Communications CNM Project – USA Division

Alfort School of Veterinary Medicine - France

www.labradorcnm.com

Excellent post Avis.  We need to keep those quality dogs in our small gene pool and many people are still unaware of CNM so its important to get the word out there and for people to understand that you can still breed a carrier to unffected but obviously puppy buyers with any intention to breed need to be aware that there is a 50% chance of their pup being a carrier so should be tested. 

Just to clarify - a carrier of CNM should never be mated/bred to another carrier of CNM.  If you have a carrier, the dog/bitch can be mated to a clear dog but 50% of the litter may be a carrier of CNM.