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Post by Deleted on May 10, 2014 8:54:07 GMT -5
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Post by Deleted on May 10, 2014 15:26:31 GMT -5
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Post by legendrockranch on May 10, 2014 22:30:17 GMT -5
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Post by Deleted on May 10, 2014 22:39:59 GMT -5
Very interesting read. Thanks
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Post by Deleted on May 10, 2014 23:13:02 GMT -5
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Post by cddexter on May 11, 2014 9:22:05 GMT -5
Pine valley. I'm curious why you point to Outlaw, since he and his whole extended pedigree have little or no white. I have photos of the Cornahir herd from 25 years ago, before David Couper downsized, and there isn't a white hair to be seen in any of the 30+ cows he ran, or in the bull. Outlaw comes from that herd.
Your crossbred bull is cream, and therefore has at least one dilute gene. Cream is the dilute of red. Except for the Dexter brown, Sheila Schmutz told me ALL dilute genes identified so far are dominant over the base coat color: it only takes one to modify the coat color. that's why there was so muh interest in the Dexter brown being recessive.
Dilute black is I believe, grey (think Murray Grey from Angus). No surprise the calf is the same color as the sire, and not a lot of guesswork where the calf inherited it from, either....
Cheers, c.
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Post by wagradexters on May 11, 2014 9:33:06 GMT -5
We never had white on any of many Cornahir Outlaw progeny. The cow mentioned above has him in the fourth and fifth generation back. That allows for quite a few other ancestors. I'd be looking somewhere else for the source of white. However, we have had the occasional slight brindling when two CO lines come together. MargaretW Au.
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Post by littlecowfl on May 13, 2014 15:10:50 GMT -5
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Post by midhilldexters on May 13, 2014 15:58:34 GMT -5
Hi Alicia, It also looks like she has white just behind her front legs or is that mud? Anyway what I was going to say was I'm not sure she wouldn't pass it on, just because you don't see it in her calves doesn't mean they couldn't be possible carriers, at least that's how I feel it should work. She would need to be bred to another carrier of what we refer to as the white spotting gene to possibly throw a calf that shows white. I'm hoping sometime in the future we can get a test for it. Can someone confirm this, but I'm sure I was told by someone that a white udder is not due to white spotting, most other white probably is. Also, who is familiar with gestational white and how would one differentiate it from white spotting?
Carol K
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Post by littlecowfl on May 13, 2014 16:50:42 GMT -5
Thanks. We breed her only to bulls with no white and it has been working for us. I suppose it's possible that there may be a hidden trait in there, but it would be only on her side and she produces some lovely black calves. Our heifers make fine dairy cows regardless. We aren't much into showing and our buyers want nicely tempered animals that make good family milk cows.
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zephyrhillsusan
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Caught Dexteritis in Dec. 2009. Member of this forum since Oct. 2013.
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Post by zephyrhillsusan on May 13, 2014 20:30:39 GMT -5
I was thinking that the white makes her nice udder easier to see. It looks like her navel might have white on it, too? Regardless, she's a striking and lovely cow.
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Post by littlecowfl on May 14, 2014 15:19:05 GMT -5
Thank you very much! She is original!
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Post by lovingmydexters on May 14, 2014 15:44:59 GMT -5
She is very pretty . Beauty is in the eye of the beholder.
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Post by kansasdexters on Aug 7, 2014 8:26:46 GMT -5
Since there are many new people on this board and the question about "excessive white markings" comes up on Facebook and other places, I wanted to share some historical information:
Sandi Thomas was doing research on "Excessive White" markings in Dexter cattle (ref. ADCA Dexter Bulletin, Sept.-Oct. 1993, p. 11), years before there were any Cornahir Outlaw or Saltaire Platinum offspring in the United States. The first Cornahir Outlaw offspring wasn't born in the US until 1995 and the first Saltaire Platinum offspring wasn't born in the US until 1994. What Sandi did have in her herd were a lot of Parndon Bullfinch descendants and she was line breeding them. That's what it takes for recessive genes to be expressed, the offspring have to be homozygous for the recessive white spotting gene, in order to be spotted (to express the recessive trait).
Daisy Moore had previously reported on Parndon Bullfinch semen being used on Holstein cows (this pied breed is homozygous for recessive white spotting), and some of the resulting calves had some white markings on their legs and flanks, indicating that Parndon Bullfinch indeed carried a gene for recessive white spotting.
A Dexter that is a carrier of the recessive white spotting gene, will not express the trait (i.e. will not have white spots or "excessive white"). If a carrier of recessive white spotting is mated to another carrier of recessive white spotting, there is only a 25% chance of the calf inheriting the recessive white spotting gene from both its sire and its dam, is homozygous for recessive white spotting and expresses the trait. There is a 50% chance of the calf inheriting the recessive white spotting gene from one parent and being a carrier of recessive white spotting, but not expressing any white spotting. There is a 25% chance of the calf not inheriting the gene from either parent and thus being a non-carrier of recessive white spotting.
The recessive white spotting gene can therefore be carried through many generations before it is expressed and a white-spotted Dexter calf is born. Because it seems to appear out of nowhere, many people assume that an illicit mating must have occurred in order for that calf to be so different in appearance from its sire and dam of record. If this is not the case, then they assume that an illicit mating must have occurred somewhere earlier in the pedigree of that animal - that there was introgression from another breed.
What they fail to consider is that this recessive white spotting gene has been in the Dexter gene pool since the beginning of the registries and that it came in with the foundation animals in the first place. Since a carrier of the recessive white spotting gene does not express the trait, any animals that were brought into the registries "by inspection" would have passed inspection since they were solid color, but some of them could have carried the recessive white spotting gene (or other recessive color genes).
So, while an illicit mating can cause this trait to be expressed (i.e. mating a Dexter to a Holstein can produce a spotted calf), the expression of this recessive trait is not sufficient in itself as proof that an illicit mating ever occurred. Purebred Dexter cattle that carry recessive white spotting can produce purebred, spotted Dexter calves. They can also produce spotted calves when mated to other breeds that are homozygous for recessive white spotting (like Jersey cattle, Guernsey cattle, Ayrshire cattle, and Holsteins).
The breed description for Dexter cattle color states that the breed is solid black, solid red, or solid dun, therefore the calves that are born with white spots (pied) do not fit this description. Internationally, some Dexter registries exclude these calves from registration. In the United States, the ADCA and PDCA will register Dexter calves with white markings, as long as they have a registered sire and a registered dam and meet the other registry requirements. The ADCA and the PDCA do not exclude purebred Dexter calves that have excessive white markings.
There is no readily available genetic test to determine whether or not a Dexter carries the recessive white spotting gene. The "test" is when a spotted calf is produced -- then the breeder knows that the calf's sire carries recessive white spotting and the calf's dam carries recessive white spotting. In order to effectively remove this recessive trait from a herd, a breeder would then have to cull the bull, the cow, and the calf. Most breeders won't do that, so this recessive trait continues to be passed down through the generations of registered, purebred Dexter cattle. It's not affecting any functional performance of the animals, so it just hasn't been a high priority to take much (if any) action on it during the last 100 years of Dexter breeding in the United States.
Patti
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zephyrhillsusan
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Caught Dexteritis in Dec. 2009. Member of this forum since Oct. 2013.
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Post by zephyrhillsusan on Aug 7, 2014 10:28:01 GMT -5
Thanks for the very clear explanation, Patti. I'm wondering, if you had a white-spotted calf turn up in your herd, would you automatically cull it and its parents? Or would you evaluate them for other qualities? I'm not asking because we've had one; I'm asking purely out of curiosity and "scientific" interest, trying to find out how much of a problem you personally think it is, because I respect your opinion and I want to learn. If you wouldn't automatically cull, I guess another way to ask my question would be how high on the list you'd put white-spotting as a reason for culling? ETA: Sorry if you addressed this earlier in this thread. I read the thread as it was going on, but I haven't re-read the whole thing just now.
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