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Post by janmar on Dec 1, 2013 15:39:30 GMT -5
I was wondering if anyone can briefly tell me what colors have to cross to get the chocolate colored calves that are starting to show up. Thank you
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Post by rhonda on Dec 1, 2013 19:35:24 GMT -5
My calves --so far-- have all been that color. My bull is that color. I have dun cows. But when he bred a black Heifer for the MDBA heifer project she had a black. The 2 bull calves I had this year are chocolate, last year 2 chocolate heifers, the year before 2 chocolate bulls. I got a chocolate color using him on a black dexter/angus cross cow--but her dad was a dun Dexter, actually she was Selby's half-sister.
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Post by janmar on Dec 1, 2013 20:02:43 GMT -5
Rhonda, Where did you get a chocolate bull?
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Post by cddexter on Dec 1, 2013 22:23:14 GMT -5
For what it's worth, chocolate is dun is brown is TYRP1. All one and the same. Tones are from modifier genes. John Potter was working on this when he got sick. H believed it was a co-dominant trait, but didn't know if it was the presence or absence of the trait. There are three versions: pale honey or wheat, in-between (hetero), and cocoa. I'd guess his cocoa is your chocolate. If you want more info, you could always contact John: j.potter@att.net but give him a few days to reply, as health-wise he's not out of the woods yet. And, always remember that testosterone affects color, too, so two animals can be the same genetic color and tone, but the bull will be darker. cheers, c.
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Post by Cascade Meadows Farm - Kirk on Dec 2, 2013 16:54:38 GMT -5
The TYRP1 gene occurs in most animals and it codes for a type of protein that acts as a catalyst to make black pigment(eumelanin) look black. Since animals inherit one gene from mom, and one gene from dad, most have two good working TYRP1 genes. It only takes one good working TYRP1 gene to make black pigment look black because the good gene is dominant over the recessive broken gene. If both TYRP1 genes are broken, then TYRP1 protein cannot be made, and any black pigment looks brown.
A chocolate/dun cow, is really an otherwise black cow, whose black pigment looks brown due to two broken TYRP1 genes.
A red cow with little or no black pigment, is mostly unaffected by having two broken TYRP1 genes.
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Post by Deleted on Dec 2, 2013 23:17:08 GMT -5
A lab explained it to me like this:
To create a Dun coloured calf, there must be the presence and interaction of three key players:
• There are TWO MC1R genes which control the level of pigment, the melanin/colour in the hair and skin. • There must be TWO copies of TYRP1. TYRP1 creates a protein. • And there must be at least ONE Black colour gene present.
MC1R and TYRP1 are not linked in any way, nor are they linked in any way to the colour genes.
The creation of the Dun colouring begins when two copies of MC1R _both_ become affected by protein created by the _two copies_ of TYRP1.
The protein from two TYRP1s causes confusion to both MC1R genes when MC1R is dealing with black pigment resulting in a dilution effect of the black pigment – hence the Dun calf is born.
The protein created by TYRP1 does not confuse MC1R when it is dealing with Red pigment.
And one copy of TYPR1 will only confuse one MC1R enabling the other MC1R to deal with black pigment as it should. And since black is dominant, the calf will be black, but carries dun
Cheers D
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Post by rhonda on Dec 3, 2013 5:06:06 GMT -5
I think the question was --Is there a way to know if you will get a lighter dun or a darker dun? For instance, will a dun that does not carry red have more of a chance to have a dark dun than a light dun? Even in red there are so many varying shades that I don't know if you can breed to get a dark red rather than a lighter one. My bull had a black momma and a reddish dun sire. But I have been getting the dark color from dun cows. I had one calf that was lighter when born but within a couple months was as dark as the rest. Probably no way to know how much the TYRP1 will affect the gene?
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Post by cddexter on Dec 3, 2013 8:31:43 GMT -5
Apparently it isn't the TYRP1 that causes the difference in tone of color, but other genes which act as modifiers. Back to the original question, John, who's done the most work on this (and got his name on the paper) says it appears to be a co-dominant, but he doesn't know if it's the absence or presence: depending on which, the pale is normal, and the dark is the modified, OR it's the dark that's normal and the light that's modified. Need to find the locus to figure it out.
and, sunlight bleaches the color, too. You can have a light dun that's kept inside during the day and only let out to graze at night, and it may (or is, in the case I tried) be dark because the sun didn't have a chance to bleach it.
It's apparently the same with some of the reds. You can have both light and dark red regardless of little e or E+. Has to be modifiers. For the most part, a red gene in the main locus isn't going to affect the tone of dun at the other locus.
Donlin, the reason I speak with some assurance is I did the original work on all this, and was peripherally involved with John and Sheila, so think I have a reasonable handle on the topic. cheers, c.
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Post by Cascade Meadows Farm - Kirk on Dec 3, 2013 11:58:42 GMT -5
TYRP1(tyrosinase-related protein 1) does NOT make brown/dun. Instead, the normal TYRP1 gene (a melanin biosynthesis gene) makes black pigment (eumelanin) look black.
Brown(dun) is caused by a defect in the TYRP1 gene. That defect interferes with normal eumelanin (black pigment) biosysthesis
The defective TYRP1 gene is recessive (as many defective genes are).
It takes two DEFECTIVE TYRP1 genes to make black pigment(eumelanin) look brown/dun
ANY cow including E+E+ reds, E+e reds, and even ee reds can have some black (eumelanin) pigment. Red cows that would otherwise have some black shading, would have brown/dun shading if they have TWO defective TYRP1 genes.
Again, it's the LACK of TYRP1 that makes otherwise black cows look dun.
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Post by rhonda on Dec 3, 2013 15:12:46 GMT -5
Gene, to me the dun in the video just looks like he hasn't shed out completely. I have one cow that looks like that till she completely sheds out.
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Post by Deleted on Dec 3, 2013 15:29:54 GMT -5
As I wrote, it was the way the lab explained it to me when I asked for more information on purposely breeding for dun. My post was a cut and paste from the email.
We have 7 duns, coloured tested (Extension) and each one is a different shade to the other and don’t appear to correlate to what colours they are carrying. Some carry wild red, others true red. We have three who are black carriers only – no red there at all.
The one thing we have noticed is the winter coat appears lighter than the sleek summer coat. And the most interesting thing we have seen is the dun shade darkens considerably when close to the birth of their calves irrespective of the season.
We have five reds, one quite rich and deep in colour (we would love to purposely breed that…..its beautiful) and the other reds are close in the shade of a lighter red. Yet they carry different combinations of the E+ & e with two also carrying dun. One carries one copy for dun and the other carries two copies of dun.
And the shade of the calves’ coats is just as interesting to watch but again we have found, to date, no correlation to the coat and their extension / dun test results.
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Post by carragheendexters on Dec 3, 2013 17:07:01 GMT -5
This came up for discussion at our promotion group's Christmas get together last weekend. What we were talking about was how the texture of most dun's hair was different to the reds and blacks. Very few dun's have that slick short hair, even in summer. The hair appears to be much coarser and more porous, one person's comment was that it was like the hair shaft was hollow. Very few duns have that short slick coat, nor do they get the shines on their coats that the reds and blacks get. Perhaps there is a relationship between the genetics of dun and fur composition. You know how black hair has a different texture and composition to blonde hair, maybe same thing in duns. What started the conversation was a lovely young dun calf, that if it was a horse you would call silver dun. Very pretty colour. regards Louise
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Post by Deleted on Dec 3, 2013 21:16:20 GMT -5
We have found the same Louise. We have two duns; EP Indiana and her daughter B Sahara who slick right up for summer. Indiana is the only one who has a shine to her coat too - the other duns do not.
Three of the duns have curly / wavy hair on their foreheads and coarse summer coats with the rest inbetween.
We also have the same variance with the reds and the blacks - its not specific to the dun.
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Post by janmar on Dec 3, 2013 21:56:56 GMT -5
Thanks folks for the information. I think I will stick with my blacks.
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Post by lakeportfarms on Dec 4, 2013 7:45:43 GMT -5
Our bull Mike and most of his male progeny all have the dark dun color. We do have a non-carrier bull out of him who seems to be a little lighter in color, but his mom is a light color dun. There is a definite difference between the dark and light color dun in the hair texture. Whether it is related to the chondro gene or not I can't say as we've had very few non-carrier bull calves out of Mike. Their hair is extremely coarse and curly.
Sheri, regarding flies, our dark dun seems to attract a fair number of flies compared to the lighter dun girls, and slightly more than the red. I have noticed however that the red cows seem to have more problems with the flies around their eyes than either the black or especially the light dun cows. They look like they're crying. Thankfully our fly season is short here. The dark dun seems to have most of the flies around the shoulders and top of the back and fewer around the face. Perhaps it's related to the longer more curly hair they have on the face than their black or red counterparts.
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