Pigment in yellow Labradors

First off there are two distinct yellows that have different "genotypes" which means genetic combinations for color. If a yellow Lab has one or two genes that encodes for black then the dog will have black pigment and this pigment can vary in intensity which I will discuss below. If a yellow Lab has two genes that encode for chocolate then the dog will have liver (chocolate) pigment also known as a "Dudley" and this can vary from very light flesh colored on a light yellow to a dark brown on a red or dark yellow. These different combinations can arise from various breedings depending on what color the parents are AND what colors they carry. Two blacks bred together for example can produce both black pigmented yellows AND liver pigmented yellows.

Here are examples.

This first dog is a dark yellow with black pigment. Notice the black around his muzzle and eyerims. His nose has faded to pink due to age. This inevitably happens to most yellows. It is often called a "winter" or "snow" nose. The cause is a breakdown of a certain enzyme (tyrosinase) that produces pigment. As a dog ages this enzyme doesn't work as well and so the nose fades. It is also temperature dependent so the enzyme works better in the warm months of the summer thus the nose will fade back to black or purple in that season. 

Now here is a dark yellow with liver pigment. Notice that not only is his nose brown but also his lips and eyerims.

Here is an example of a young dog with black pigment.

Here is an example of a 3 year old yellow with black pigment whose nose has begun to fade.

Now pigment on black nosed yellows can vary. Some have very little black around the eyes and muzzle. Some have noses that begin to fade as puppies and never turn back to black while others keep their coal black noses until they are seniors (8 years +). Most begin to fade around 2 years of age. Usually pigment does darken as a young pup ages and if the nose is purplish at say 5 - 6 weeks it will most likely turn black by 8 weeks but not always. Intensity of black igment is controlled by a separate set of genes to coat color. Breeding a poorly pigmented yellow back to a black may not correct the pigment in the resulting puppies. The best way to do so is to go to a yellow dog with really good black pigment or a black or even chocolate that is from a line with good pigmented yellows.

Liver nosed yellows can be predicted in some breedings but many times they come as a surprise so some responsible knowledgable breeders will produce them from time to time. The most common case is the breeding of chocolate to chocolate. It is relatively uncommon for a chocolate to carry yellow so the chances of BOTH parents carrying the color are slim but it does happen. Yellow and chocolate genes can be passed down the generations and so some assume that say a black doesn't carry chocolate because no chocolates appear in the pedigree for many generations but that is not always so. The black could carry BOTH yellow and chocolate and be bred to a yellow that happens to carry chocolate and voila both types of yellow pups can arise.

You can know definitively in some cases especially if a stud has been used enough times and only produced one or two colors. If a black that carries yellow is bred to another black that carries yellow then there is no chance of producing a yellow with liver pigment. If you don't know for sure what each parent carried then the only sure why to tell what colors your dog carries is to have them color tested through DNA coding which costs about $85.00.

Unfortunately many breeders are not well versed in coat color genetics and there are "old wives tales" surrounding liver nosed yellows. First of all they are a fault, not a disqualification.  Only a dog that has true pink pigment can't be shown so producing a beautiful pup that can't go in the ring is unfortunate BUT they do make wonderful companions and hunting partners so not all is lost! Second they do NOT have inherent skin problems nor do they get sun burned like many breeders have been told. They are "self colored" just like a chocolate Lab or a red Visla and there is nothing genetically wrong with that combination that makes their skin sensitive. And lastly they do not "pop" up in litters that can't produce the genetic possibility. In other words both parents MUST carry both chocolate and yellow to yield liver nosed yellows.

A true Dudley (pink pigment) can and generally do have the tendancy to sunburn, so you do need to be careful of them in the sunlight.

One more note. Many other breeds allow a yellow/tan coat to be paired with liver pigmentation in their standards. These include the Pointer, Setter, Beagle, Shar-pei, Chow Chow, Chihuahua plus many others. In the Labrador the originators of the standard simply did not like the appearance of the liver nosed yellows. Back in the early part of the twentieth century when the Labrador was being cultivated in the U.K. chocolates AND yellows tended to have very light eyes (like a Chessie) which gave them a harsh expression. The original Labrador standard called only for black coats and then yellows were actually given a separate standard but they were soon incorporated in with the black coated individuals. Chocolates were always present because liver is recessive to black in all dogs. Once the three colors were recognized in the standard, the combination of chocolate and yellow was not asthetically pleasing to those that were breeding Labradors and thus they were frowned upon.

DUDLEY

What is a Dudley?  You're going to get different answers from different people.  A true Dudley is totally lacking in pigment.  Its nose, eye rims and feet are as pink as the day they are born. 

Now, remember, the origins referred to the Bulldog with liver pigment. In other breeds, it has come to mean non-pigmented, as it does in the Standard for the Labrador.

Many say a yellow with liver pigment is a Dudley. It depends on the person and their definitions. The AKC describes it as flesh colored. In Anna Katherine Nichols book of the Labrador Retriever, written in 1983, the Dudley nose is defined as flesh colored.

The LRC defines a Dudley as pink.  A yellow with chocolate pigment, whether its light or dark, is not a Dudley.  It should be penalized, but not disqualified.

The AKC standard states:
The DQ for pigment reads, "A thoroughly pink nose or one lacking in any pigment."

In the Canadian standard, it states that the yellow's pigment is black or dark brown. Anything else is a serious fault (as the Dudley nose in the US had been throughout history).

A yellow with a brown/chocolate nose is NOT lacking in pigment, so they are not a Dudley and should not be referred to as such.

The dog above could not be shown, but the lack of pigment does NOT mean it can't still be a beloved pet.