Early color entries of interest

[jamshundred]

As more and more registrations are entered I think there are more and more clues that dun was in the earliest Dexters and eventually there will be an identification !   I am fascinated by the number of "red" animals that were in the early listings.   Below are two Dexters from DCS herd book 1 that were entered recently.  The color is highlighted.
Also, the often pictured black bull Limelight sired several Dexters registered as red.   

[teatpuller11]

Thank you, Judy.  If brindle was acceptable back then, why is it not acceptable now?  With all your research, have you found out anything?

[jamshundred]

I find myself usually to be more content when my focus is on Dexters past rather than Dexters present.

Your question is a good one, and I do not ever recall seeing Brindle actually excluded ""officially".  It just seems to never have been "officially" included.  I shall have to remember to ask the Brits if there is an official exclusion of Brindle.

 In the US everything is permitted.......standards and guidelines are not enforced in any manner.   The breed has evolved into something we should be registering in the US as a new breed called Chestersons for  Dexters have dwindled to a small percentage indeed.

Judy

[teatpuller11]

Chestersons?

[cascade]

Dun as a genotype is simply a broken TYRP1 gene. TYRP1 is an enzyme that helps make black pigment(eumelanin) look black and stay black. Those broken (loss of function) TYRP1 genes can be found in nearly every breed of animals from mice to cats to rats to pigeons to dogs etc... Broken TYRP1 genes typically make black (Eumelanin) pigment look brown because the missing TYRP1 enzyme can't do its job and the supposed-to-be-black Eumelanin pigment fades to brown.

Pheomelanin is the pigment that is red. A supposed-to-be-black dexter with two broken tyrp1 genes, is going to be brown, but if it has lots of pheomelanin, then the brown-looking faded eumelanin is going to be tinted with lots of red.

The 1900 breed standard is very clear in stating the PHENOTYPE of dexters should be solid black, or solid red..... Not brown, Not tan, not striped. So regardless of what genes were floating around in dexters, the original standard said we should select toward solid red-looking and toward solid black-looking dexters, so purposefully selecting toward brownish-looking, or tan-looking, or striped animals would have been off standard.

A dun genotype would have been acceptable, only if the animal had other factors that made it produce a lot of pheomelanin, to make the animal look very red, instead of brown.

So, bottom line is that brownish looking dexters aren't traditional as is clearly documented in the 1900 breed standard.

[teatpuller11]

thank you, cascade.

Is this why I've read about the dirty oak table Dexters being culled? Why do we have dun Dexters today? If it is a new color, and if so, why would it quality for Legacy status?  This brings me back to my original question in the other thread.  If all these off traits started out in the breed but were weeded out, why oh why the change of heart?

[jamshundred]

A bit of reality is needed on this issue, is it not?  In 1879, 1899, 1909, 1919. and well into the latter part of the 20th century. ... there was NO science and little information as to the genetics of color in livestock.   Of course there was dun in all of those decades.  There HAD to be.  As the earliest herd books are entered from England, the numbers of "red" cattle are astonishing. . . . since we had so few in the US, and some of these animals imported first from Ireland were RED, and descended from herds heavy in red, but it was lost, as was any dun that might have existed and been registered as red.    Until the 1960's, there was NO knowledge of Dun.  It existed in the gene pool but it was unknown to breeders.  In the US it was called AND registered as red, just as it had to have been in England.    That it was not a known or named color, therefore not in the breed description does not mean it didn't exist.  I have traced dun to within a generation of foundation.   I don't think it a coincidence that many of the cattle registered as "red" had names like Amber and Goldie.   

I will prove you wrong Kirk. . . . . . .red-dun Dexters . . .. WERE. . . . .  .in the early herds.   They called them RED.   They also called them RED in America.

I am thinking of new features for the pedigree searches to make it easier to track and trace the colors, but it won't be soon.  All available funds right now are going to forensic genotyping of skeletal remains which costs $275 a speciman.

Judy

[cascade]

Red = Pheomelanin (red pigment)
Dun = Eumelanin (black pigment, but without functional TYRP1, it looks faded brown)

Some genetic duns have almost no pheomelanin and so they look completely brown.... nothing red about them.

Here's a dun with faded eumelanin and little or no pheomelanin.... this brown (dun) cow doesn't look red at all.



Here's a red with lots of pheomelanin and almost no eumelanin.....  this red looks nothing like the brown cow above.




Some genetic duns can have quite a bit of pheomelanin (red pigment) and can look very red.  Phenotypically, one would just call them red.    Because the 1900 breed standard allowed only black or red phenotypes,  any brown looking dexters would have been thought of as substandard.  A genetic dun that was very brown might have been culled, while a genetic dun that looked very red, would have simply been called red.  

[jamshundred]

Kirk,

I am going out on a limb here and say that I think the "red" cattle ancestors that carried the dun gene, were the deeper reddish duns that Americans also believed to be red.  I never saw one of the tan/brown/blondish duns until about a dozen years ago when there was a photo on the Bulletin that showed a herd of Dexters and in the middle a light colored animal.  I knew the owner and in passing asked what breed it was or if it was an outcross and was completely surprised to be told it was a Dexter.  Later I was given a photo of the Woodmagic herd standing in front of the barn and there were tan Dexters in the photo.

This is my opinion, not science, but I think when Mrs. Rutherford closed her herd and line bred the dun genes were changed and set with time to the lighter shades.  I will remind you that the earliest dun cows in the US descended from the mid 1950's imports from England to the US, ( Grinstead, Framfield, Atlantic carriers of dun), but the later, lighter colors I have seen have always traced to Woodmagic.  I suspect research on the genes of the dun in the cattle with no WM ancestry and the Woodmagic descendents might turn up some interesting differences in the color genetics.

Judy

[cascade]

In addition to the extension locus (D, E+, e) and the Brown(dun) Locus (b, B), there are other loci and alleles that have an effect on pigment. It's possible that there are some recessives at these other loci that kill the production of pheomelanin (red pigment) if two of these recessives are present. If a dun animal had two of these other red-pigment-killing recessives, then they would look very brown/tan.

Linebreeding does a good job of finding existing recessives and doubling up on those genes so you can see them. It's possible that those possible recessive red-pigment-killing genes are rare throughout Dexters, but if Woodmagic had one of those genes, her linebreeding could have helped increase the frequency in her herd, and then spread them elsewhere since Woodmagic animals spread so far and wide.