Is Breeding a Chocolate Labrador to another Chocolate Labrador Bad?
Are Chocolates "weaker" than the other colours?
Not NecessarilyAs far as my research has taken me, I cannot find that breeding Choc to Choc is in itself bad.
Read the note from Pam Davol (below) when I asked her advice. Pam has a human medical background (B.S., M.Ed. is a research scientist in the field of biochemical oncology (cancer) and experimental pharmacology) and is a longtime breeder of Labradors. Her web site is Wing and Wave.
The reason that there seems to be more problems with Chocolate labradors in any particular geographic area is probably due to line breeding and in breeding within the area. More advice and definitions from from Pam Davol is detailled below.
The more ancestors that the dogs have in common, the higher the chance that "bad" recessive traits will be expressed. Nothing to do with the colour of the coat, this would be true of all colours of lab and indeed all breeds of mammals (including humans!)
"Style" and Breed Standard
Breeding Chocolate to Chocolate where one both parents have a recessive gene for yellow, will produce lighter eyes in the Chocolates, variation in the coat colour, and yellow dogs with "pigmentation faults", yellow coat colour but "chocolate or liver colored eye rim, lower lip, and nose pigment". Pam's words on this issue, see below.
But if you want a family pet and are not going for the show ring, these "faults" are in the eye of the beholder.
Strength of Type in the Blacks
A general belief is that the Black dogs have a better record for "Conformity" - adhering to the "Breed Standard". The closer to the standard a dog is, the better it will be built to be a working Labrador - minimising the chances of the underlying bone structure of the dog causing hip, shoulder or elbow problems.
So, further to this belief, is that if the Chocolates are bred to a well conforming Black, the resulting Chocolates will be of higher quality.
The Black coat and eye traits passed on will also ensure that the Chocolates will have darker coats and dark eye colour - a preference for the show ring.
Look at Chocolate Labradors bred to the standard, type 1, and bred for other reasons, type 2. To my eye, the main difference is the head shape, with the conforming Labs having the "broad skull" you would expect to see. The "type 2" dogs seem to have a narrower skull and lose the typical labrador look - people often mistake them for German Shorthaired Pointers. They would still be lovely dogs, bred for their temperament only, not for their looks.
More informaion on
Astrochoc's Recent ExperienceKnowing about the recessive yellow issue and my female carried a yellow (bbEe), I looked for a stud dog who was dominant on the expression gene (bbEE). I found a quality stud with this genotype (ie he had never produced yellow pups when mated to a yellow female), and checked his pedigree chart for ancestors in common with my female. Look at Sires pedigree, and Dam's pedigree.
The stud dog was also chosen because he was not a tall dog, because my female tended to be a bit leggy - ie she is about as tall as a female Lab can be within the standard. Also he had a lovely friendly happy temperament.
I don't have enough information to judge why 2 of 6 of the pups of this mating have come out with OCD in their elbow. Perhaps it is just random genetics and very bad luck for us all.
So this result is a warning to breeders and buyers to lessen the odds by finding out hip and elbow scores and PRA outcomes for as many dogs as they can in any given pedigree before breeding or buying decisions are made.
As stated before, nothing can absolutely guarantee that any given litter or your pup will have no problems. We are at the mercy of the randomness of genetics.
If ALL breeders took the actions of minimising the risk of passing on the bad traits, then the chances of getting a bad outcome will lessen over time. So carefully choose a breeder who is taking all the steps they can.
I have been getting many inquiries on this particular topic. Apparently, someone on one of the forums has indicated that breeding chocolate to chocolate increases risks for skeletal disorders, etc. because the gene responsible for chocolate is a recessive.
Although there are disorders linked to some coat color genes, these genes are typically only those that occur in absence of color (such as albinism) or in the case of the dominant Merle allele (produces the patches of blue and yellow observed in some breeds) which when inherited from both parents may be either lethal to the offspring or produce eye and hearing disorders (the dominant form of this gene is not present in the Lab). The recessive genes for chocolate and yellow in the Lab have not been associated with any physical abnormality or disorder, nor has any genetic defect been documented in the medical literature as having a relationship to carrying the recessive alleles that encode these colors (either alone or in combination). As to OCD: OCD affects black Labs as well as chocolates and yellows, the latter of which both carry recessive genes for coat color. Certain litters are predisposed to developing OCD but documented factors that influence expression of OCD in a particular dog do not include coat color.
Some genes, like those for some forms of cataracts and one form of retinal dysplasia, do occur as incomplete dominants, however, not all incomplete dominant genes have deleterious side effects (similarly, not all recessive genes are bad). Sometimes, coat color genes will behave as incomplete dominants (this is particularly true of the agouti--A locus-- genes for coat color), however, these genes do not result in any deleterious side effects. This is true of many incomplete dominant genes, even in humans. To put it in context: Blaming every coat color incomplete dominant gene or recessive gene for physical defects in dogs would be the same as saying that every person out there with green eyes (due to incomplete dominant) or blue eyes (due to recessive) is at higher risk for genetic defects! "Line-breeding is a breeding in which a dog and a female are related going back 2 generations or more. There are various degrees of line-breeding depending on how often one or more particular ancestor(s) appears in the pedigree (family tree) of both the dog and the female. In "tight line-breedings" the pedigree from both the dog and the female will appear the same at some point, that is, both will have the same ancestors behind them. In-breeding is the tightest form of line breeding, in which the pedigree of both the dog and female are virtually identical. In such a case, the highest degree of in-breeding is breeding sister to brother, followed by mother to son (or father to daughter-- genetically, parents are half-brother or half-sister to their offspring). The purpose of linebreedingg or in-breeding is to assure consistency of genetic traits in what one produces. The more frequently an individual dog appears in a puppy's pedigree, the more genetic influence that ancestor will have on that puppy's appearance, temperament, etc. In-breeding is the quickest way to accomplish genetic purity. So why don't more breeders in-breed? There are also dangers to in-breeding. Mainly, one of the ways that in-breeding produces genetic purity is by allowing for the expression of recessive genes which can then be eradicated from the gene pool. The problem is that many recessive genes are responsible for hereditary disorders. For this reason, in-breeding may result in up to half of the litter developing disorders related to recessive genes; however, the remaining half of the litter will be genetically pure of the disorder. This 50:50 risk is not something many breeders wish to chance. In addition to risking genetic disorders, inbreeding will result in progressively smaller litters and eventually infertility in future generations." "My own preference is for the black coloration. There is something very photogenic about the way the sun shines off of the coat of a black lab after a swim. Yellow and chocolate dogs just look like wet dogs. The yellow labs are probably the most popular among the owner population. The chocolates aren't very popular for showing. One reason, I believe is that the coats of the chocolates can be very troubling at times. During the Spring and the Fall when they are going through heavy shedding periods or "blowing coat" they are often two-toned, and in the summer, special attention must be given to be sure that the sun doesn't bleach out their coats. From a breeding standpoint, when one is breeding for yellow, it is probably best that one doesn't breed for chocolate at the same time. Presence of the recessive epistatic gene for yellow can cause coat dilution in the chocolates and light eye coloration, conversely, the presence of the recessive chocolate gene in yellows can cause pigmentation faults (chocolate or liver colored eye rim, lower lip, and nose pigment). Even when not breeding for chocolate, the combined presence of the recessive chocolate and recessive yellow in a black dog will result in a lighter eye color. I may at some point in the future breed for chocolate, but I will not be breeding for yellow when I do. "