Blue Roan Question

[mark tenenbaum]

Thanks Ohio Breeder-If they had 1/3 of that info at cattle visions et al-they would sell alot more semen-and I love them old Cumberlands-I had a 1990 who still looked great in 2006-just quit breeding.PS-I have also seen a few blues out of white (black nose or black tinged ears) shorthorns-that go back to angus. O0

 

[Mark H]

One way to get a blue roan is to use a breed that has the blue roan pattern has the bred standard namely the Speckle Park:http://www.codiakacres.com/.  The breed has plenty of Angus and Shorthorn in them so they are a British type breed.  They also tend to be easy calving. 

 

[kfacres]

Please correct me if I am wrong, but I don't believe that there is such a thing as a "WHITE" shorthorn.  Any "WHITE" shorthorn that I have ever seen always has some red hairs in their ears or on their switch.  I believe that what we call a white shorthorn is really a very light roan.

I think this is correct, I have never seen a Pure White Shorthorn either, and from past discussion on here, can't say that I've ever heard of anyone else seeing one either.  I think to be a pure white, it needs to also have pink eyes... Although not required... 

Most whites, are in fact, VERY VERY light roans...

 

[jaimiediamond]

Please correct me if I am wrong, but I don't believe that there is such a thing as a "WHITE" shorthorn.  Any "WHITE" shorthorn that I have ever seen always has some red hairs in their ears or on their switch.  I believe that what we call a white shorthorn is really a very light roan.

I think that the red on an white animal shows pigmentation which is found around the ears, eye lashes and a few red hairs in the switch this  is proving that the animal is a white instead of a dilutant such as a Charolais.  With that said there are so many registration errors regarding colour there very well could be roan registered as white as there are definitely roans registered as red!!!!

 

[KSUwildcat2009]

OH Breeder is correct.  Roan isn't carried in the sense that the genetic defects we talk about are. 

The MGF locus has 2 alleles that are co-dominant.  IRIR gives you a solid, pigmented animal (black or red for example).  Ir Ir gives you a solid non pigmented animal (white).  IRIrgives you a roan.  The pattern of the roan isn't understood fully. 

The answer to the question is if you breed a white shorthorn to a homozygous black bull you should get a blue roan 100% of the time, in theory.  A roan shorthorn to a homozyogous black bull would give half blue roans, in theory. 

Coat color is complex.  It goes way beyond the scope of MC1R (black/red) and MGF (roan). 

 

[Hilltop]

Seen a pretty good blue steer a few years ago. I thought they said he had NO Shorthorn in him but was Maine, Simmi X. I am not a genetics whiz so is that possible?? Or did he have some Shorthorn in him?

 

[KSUwildcat2009]

I'm not 100% sure on that.  The easiest explanation is that he did have some horn in him along the way, they just didn't know or weren't told about it.  You'd have to do some research on what alleles are present in each breed.  Eventually I hope to have this whole coat color thing licked and on the record but until then.....  ??? Like I said, coat color is complex.......

 

[twistedhshowstock]

Coat color is the most complex genetic thing we have.  The AQHA has been trying to nail it for years and still dont have it down.  When you try to register a horse and cant tell what color his coat actually is, they have an entire department that does genetic research and tries to figure out what genetically is the most likely of the colors you think he may be.  Its because these alleles work in more of a codominance type relationship if you want to say they have a dominance relationship at all.  If it was true codominance then an angus to a white shorthorn would produce a blue roan 100% of the time, but that isnt always true.  There are a lot of factors to consider.  Hair color isnt the only thing that works this way, things such as height work in much the same way.  An extemely tall person having a child with an extemely short person does not always result in a child that is average height, and we consider that to be a true codominant trait.  They are also considering that some of it may be sex linked, so the way it expresses itself may depend on which chromosome each individual allele is located.  For instance, in humans color blindness is most commonly only found in men because the recessive gene that causes color blindness is almost always found only on the Y chromosome. There is a lot of research going into hair color, but everytime they think they are close to figuring it out, they find some other factor or variable.  I personally am not holding my breath for the day its an exact science.

 

[Endless Meadows]

I can't guarantee that I am totally correct and if someone is positive, please let me know, but as I understand it:

The roan gene could best be described as a 3rd variant in the color scheme, neither dominant or recessive, but rather incomplete (or co dominant I can't remember which is which)
An animal with one copy of the white gene will be roan with the major coat color determined by the other gene
An animal with 2 copies of the white gene will be white, or so appear that way.  there will more than likely be some red around the eyes, nose, inside the ears...

A white shorthorn (2 copies of the "white" gene) should ALWAYS throw a roan.  The extent and pattern of the roan can be influenced by many factors that I'm sure many, myself included, don't understand.  Just remember roan is the presence of white hairs amongst other colors.  If you have an animal that "should" be roan but doesn't appear to be look for a few white hairs in the brisket, belly, twist.... or shave their head and what you thought was black might now look silver.

One other thing to keep in mind with all of this is the "white marks"  markings are completely different genes.  The nice even colored roans and the "rednecks" are still both roan and have a "white" gene but the additive effects of the white marks make the two look totally different.

 

[KSUwildcat2009]

TwistedH, be careful when you talk about height.  Height is considered more of a quantitative trait because there are many genetic factors that go into it as well as the environment playing a roll.  I haven't heard the sex influence on coat color, interesting idea.  The colorblindness thing is due to it being X linked, not Y.  Females can also be colorblind, we just see more males being colorblind due to them only having one X chromosome.

The biggest problem with coat color research is correct classification of  an individual.  Even the group that found the causative mutation for roan at MGF misclassified some animals and figured it out when they genotyped animals.  http://www.springerlink.com/content/nfr4gn416w1ymugx/

The markings and patterning of roan is a whole other can of worms like Endless said.  KIT is an important gene that is involved in patterning.  If I'm not mistaken, its got ties to Hereford patterning and baldies.  There's 11 (I think) mutations in the same gene in horses that cause varying patterns.  It really is an interesting topic.  If you're interested, go to Google Scholar and type in bovine coat color.  Plenty of info out there and still no definitive answers.  Like everyone is saying though, coat color is complex. ;D