# LWO Positive - LWO Negative ???



## SWA (Jan 23, 2007)

LWO Positive - LWO Negative ???

What does each one mean? What is the good or bad of each...or rather advantage/disadvantage, if any? Was just wondering about what LWO is, and what does it mean to be positive or negative with it? Thanks so much for any help.




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## Songcatcher (Jan 23, 2007)

LWO stands for Lethal White Overo. It is the gene that can produce Frame Overos. In homozygous form, it is always lethal. LWO positive means the horse carries the gene. LWO negative means the horse does NOT carry the gene. Two LWO positive horses should NEVER be bred to each other as it could result in a foal which is homozygous for the gene and would therefore die within hours of birth.

In homozygous form, the intestine is incomplete and the foal will fatally colic.


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## targetsmom (Jan 24, 2007)

Is LWO good or bad? It depends! We have a LWO+ mare (we breed Pintos) and before we got her tested I told my husband that there was not "best result" for the testing, just that WE NEEDED TO KNOW! If a horse is LWO+ they can produce the frame overo Pintos which seem to be very popular. You need the LWO+ gene (one copy) for that. But 2 copies of the gene produce the lethal white foals, so as long as you test and don't breed 2 LWO+ together, you are fine. So because she is LWO+ we have to test every stallion we might breed her to. If she had been LWO- (or not a carrier of the frame overo gene) then we could safely breed her to any stallion. We could still get pinto babies (since she is a pinto) but wouldn't get frame overo pintos unless the stallion was LWO+.


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## bpotze (Jan 24, 2007)

When I first found out my stallion was LWO positive...I knew very little about it...and still don't know very much..other than to be sure I test most mares that I breed to him. So far every one of the mares I have tested has been negative..there for safe to breed with my guy. I had the horrible experience of buying a mare that was bred to my stallion from a breeder who obviously didn't know about the breeding disasters that can occur by crossing two LWO positves. A tiny little LWO filly that I had to have put down after a few hours. It was just devastating to me and my grandsons....to hold that tiny baby girl in my arms as the vet put her down. I have heard that there are some people who are willing to take a risk and go ahead and breed a positive mare and stallion...knowing they can get awesome colored foals......Not me!!!

Here is a picture of my stallion and the mare that are LWO positive. Not the greatest pictures...I apologize.


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## SWA (Jan 24, 2007)

Thanks so much for all the great information. WOW, I had no idea that could happen, that they could be born with fatally internal deformities like that.

Bpotze, I'm so sorry that happened for you and your grandchildren.



Your stallion is handsome, and your mares are beautiful. Hope you have many happy healthy beauitufl babies with them.



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After reading all the responses, I was wondering now, what can kind of pintos can a LWO negative produce? Just anything but Overo? What is a "Framed Overo"? Would love to see a pic of what one is, if anyone has one.

Thanks again for all your help.



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## Meavey (Jan 24, 2007)

LWO is the gene that makes the gorgeous frame overo pattern.

They call it frame because in general it looks like the horse has been framed, if you look from it from the side, the white markings are in the middle of the body and back and legs are dark.

Remind yourself that frame horses can alos carry any other pinto pattern like splash and tobiano, so it can be mixed.

Why is the gene called Lethal White Overo?

Because if two horses with the gene are bred together you have a 25% chance that both parents give that gene to the foal, if that happens it will be homozygous for LWO, the resulting foal is usually born almost or completely white, itÂ´s looks like there in nothing wrong with the foal at first but a homozygous LWO missed a piece of his intestine and thatÂ´s why it dies it can never poop.

so thats why it is called lethal white overo, because of the color the foal is born in and that it wil die, because of the missing part of the intestine.

There is another post about LWO on page 2 and if you do a search with the search button you can read a whole bunch of other topics about it.



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## targetsmom (Jan 24, 2007)

One of the problems with the "frame overo" is that not all the horses that carry the LWO+ gene LOOK like frame overos. For example, neither of bpotze's horses look like a "classic" frame overo - the stallion seems to be a tovero (frame overo plus tobiano but he could have other pinto patterns too) and the mare looks solid in the photo, but has a blaze. Our frame overo mare is gray which complicates it a bit, but she might pass for solid anyway.





There is a photo of her sire on my website (see link below) - he is a classic frame overo. Because I don't own him, I don't think I can post his photo here.

All our other pintos are tobianos, and can produce more tobianos. A tobiano (like our stallion who is LWO-) crossed with a LWO+ frame overo (like our gray mare) can produce frame overo, tobiano, or tovero. Those are the main patterns anyway!


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## vvf (Jan 24, 2007)

*Just anything but Overo? What is a "Framed Overo"? Would love to see a pic of what one is, if anyone has one. *

Thanks again for all your help.



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Here is a frame filly of ours






and a colt


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## bpotze (Jan 24, 2007)

What makes a frame overo? All these color patterns have got me confused. I have looked and looked at the color patterns and it just doesn't always make sense. I too would like to see more frame overos.

Thanks

Becky


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## SWA (Jan 24, 2007)

Thanks so much ya'll, for the photos and additional info.





Meavey, I will do a search for those threads and read up some more. Thanks.



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Vvf, WOW, that filly of yours is GEORGEOUS!



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## chandab (Jan 24, 2007)

I have a very small herd, only 6 horses including my stallion. He doesn't look even remotely frame patterned, but I'm going to have my stallion tested for LWO; if he's negative, I don't have to worry about testing my mares (one is by a LWO+ stallion, one is pinto and one is out of pinto mare). This hopefully covers my bases with just one test, at least til I have to buy a new stallion.


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## hairicane (Jan 24, 2007)

Hi, Tanya, we have a lot of frame overos. Here are a few.

Mark is a fairly classic frame with white on both sides of his neck and barrel and bald face, blue eyes.






Cisco is a very minimal frame having small white markings on both sides of his barrel. Both Mark and Cisco both carry splash overo too.






Dancer is another frame






This amazing filly is sired by Cisco out of a splash overo mare. To me she looks more splash but tested LWO + and homozygous for black.






Here is another minimal frame overo, Kid. He has white on both sides of neck and body too.


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## Meavey (Jan 25, 2007)

This is my new mare Dance, she is a tovero, LWO postive so frame and also has tobiano.

SheÂ´s also homozygous for black.






But soms horses donÂ´t show typical markings at al, there have even been completely solid ones.

(ThereÂ´s a theory that frame needs another pattern like sabino to make those really wild markings.)

Rowdy was a frame too for example.


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## targetsmom (Jan 25, 2007)

We did the same thing Chandab is doing with our herd of six minis. We had our pinto stallion tested before we bought him, and he is negative so we don't need to test the mares. Of course, in our case, we would not have bought him if he was LWO+ because we knew we had one LWO+ mare.

And a good comment about Rowdy - I know several solid looking horses with Rowdy blood that have tested positive for LWO. That is where our gray mare got the gene. I wonder if the breeder of the LWO foal that was mentioned in the original post had any idea that his horses were LWO+? I know of another case where someone got a lethal white foal totally unexpectedly, also from a tovero stallion and a solid looking mare. I doubt that there are many minis breeders who would consider that to be high risk mating.


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