OLWS Question

[I'm breeding to a Paint stud this year that is OLWS N/O. My mare is a Quarter Horse, so do I need to have her tested? I was so stupid, I bought this breeding at an auction and saw the OLWS NO. So I thought that meant NO he was not a carrier. Then I saw him advertised somewhere else and the slash was put in. So now I'm worried, what do I need to do? I talked to the stallion owner and she herself wouldn't be worried about it. So I just need your opinions.

Being your mare is AQHA and not an Overo or Tovero APHA, I wouldn't worry about the OLWS.

I guess the only time I would be concerned is if your mare is a loud aqha mare lots of white some roaning etc... my stud marks most of his foals with roan spots which I believe are a type of paint marking and he is aqha with lots of color. I have often wondered if I should have him tested if I breed to an owls mare. Will probably do so if the situation arises just to be safe. The mare in my siggy is a DR SBP but has multiple large roan spots on her..

OWLS is carried by the Overo pattern "Frame". While your mare most likely doesn't carry it... there is still a chance. I have a splash Overo colt that has minimal markings... he carries it, but its minimally expressed.



I've seen two solid APHA horses produce loud colored offspring. Lots of them kind of "hide" the overo patterns subtly. Look at BlueJays stud, He carries Overo, just minimally expresses it.

So personally I would test her, that 25 dollar test is worth putting an ease to your mind, as well as hopefully eliminating the possibility of a lethal foal. Better safe then sorry!

I personally don't have a problem with OWLS. If you tried to eliminate OWLS, you'd never have a frame overo. You just have to practice knowledgable breeding to ensure you're not breeding for a lethal.

Lynn M. wrote:

I guess the only time I would be concerned is if your mare is a loud aqha mare lots of white some roaning etc... my stud marks most of his foals with roan spots which I believe are a type of paint marking and he is aqha with lots of color. I have often wondered if I should have him tested if I breed to an owls mare. Will probably do so if the situation arises just to be safe. The mare in my siggy is a DR SBP but has multiple large roan spots on her..

I would say he possibly carries Rabicano? has he ever produced a foal with a "coon tail"?

I don't have a clue what the OWLS N/O means... I thought they were either negative or positive for carrying the gene... and most overos do.

Depending on the bloodline of your quarter mare, is what you have to look at... if those particular lines throw high white, crop-outs, etc., you better get her checked.

To be on the safe side, and since you haven't ever experienced a lethal - and I hope you never do, I'd get your mare checked. That is the absolute worst thing to have to do to put down a "normal looking" foal...I had to put down two of them... then I went on the hunt for a quarter stud - thus Kid.

Well my mare is a Bay with a blaze. Her bloodlines are Impressive , Conclusive, Formally Attired to name a few. In fact, in my avitar its her fat backend you see. I couldnt figure out how to put a picture on here.(yes computer stupid) She has only ever had one foal and thats the chestnut by her. I should probably just get her tested. I didnt understand the N/O either but now that I think about it why wouldnt it be. HYPP is N/H I just wish they would go with N for neg and P for positive.
Thank you all for your help.

I would assume the OWLS N/O would be their attempt to explaining he is a carrier of OWLS.

and to put images on here, upload them on a free account on www.photobucket.com and copy the IMG tag (do believe it is the bottom one), and paste it in your post

I've been wondering about this myself, so I Googled it this morning... Here's what I found as far as the N/O stuff...I still don't quite understand the N/O - either he's a carrier or he's not... but here ya go...

Horse breeding programs specializing in overo have particular challenges compared with programs for other white patterns such as tobiano. Not only is there the possibility of producing a solid dark foal without the overo pattern but there is also the risk of producing an all-white foal that dies of complications from intestinal tract abnormalities (ileocolonic aganglionosis). As far as we are aware, overo horses themselves have no specific health risks. While breeding evidence shows that some overos are heterozygous for a gene that is lethal in the homozygous condition, it has not been easy to identify which horses have the overo gene that is associated with the lethal white foal syndrome. Occasionally even solid-colored horses without obvious body spotting patterns have been reported to produce lethal white foals. Clearly the spotting pattern classified as overo is phenotypically and genetically heterogeneous.

Breeders can test horses for this mutation to avoid producing lethal white foals and to identify new pedigree sources of the overo gene that may be useful in their breeding programs. The gene appears to be associated with horses often characterized as "frame-overos" in Paints and Thoroughbreds, but is also present in some tobiano/overos, some solid-colored (breeding stock Paint) offspring from overo matings, some tobianos and Quarter Horses without obvious evidence of the overo pattern. The gene has also been identified in an overo Miniature Horse.

Using the letter "O" to symbolize the DNA sequence of the lethal white (LW) overo gene and "N" for the sequence of the non-overo, then the lethal white foals can be symbolized as OO, their overo parents as NO and non-overos as NN.

Breeding predictions between LW overos (NO x NO):

N O
N 25% NN solid 25% NO overo
O 25% NO overo 25% OO lethal

Breeding predictions between LW overo and solid (NO x NN): No possibility of lethal white foals.

N O
N 50% NN solid 50% NO overo

We know of no other mutations that are associated with lethal white overo horses. However, owners requesting the diagnostic test should understand that there is the rare possibility that two NN horses could have a lethal white foal due if both the sire and dam carry a mutation at a site other than the one detected by this test

That helps me a little on understanding. It doesn't take much to confuse me.

Me either... HA!

I was like, oh, for criminey sakes, either say he's a carrier or he's not - how hard can that be.

So what'd you end up doing, by the way?

I guess I should have her tested. Everyone says don't worry about it. But its probably better to be safe than sorry. All I know is I have learned that NO doesn't really mean NO. I'm glad to hear some others were confused cause I was really feeling kinda stupid.
P for positive N for negative is just to simple I guess.

Mare wrote:

I guess I should have her tested. Everyone says don't worry about it. But its probably better to be safe than sorry. All I know is I have learned that NO doesn't really mean NO. I'm glad to hear some others were confused cause I was really feeling kinda stupid.
P for positive N for negative is just to simple I guess.

LOL nothing can ever be simple , OWLS is carried in frame overo's specifically... However, sometimes frame can hide with a splash, or a tobi, and sometimes even on a solid. Point is, there is always a possibility with any horse with overo lineage. One can hide in the other, and one can hide on a solid... Overo can hide, tobiano doesn't.

Well, it's OLWS (Overo Lethal White Syndrom) and some QH do carry it.. According to APHA it has been found in them. N/O means you have one positive for the lethal gene (simular to N/N and N/H).. There is only a 25% chance when you cross two with a + gene to get a lethal. I would not worry about it at all with a QH.. I would on a paint though..

I have had to drill this in my head and this info comes right out of the APHA book.. So, we should all believe it,, RIGHT !!!

Bluejay, totally agree. The OWLS gene came from quarters to begin with... course that's also where overos came from... the beginning of the APHA from crop-outs.

I also noticed on that article, that some tobianos throw it as well....I'm assuming they'd have to have an overo something in there somewhere...

7 True.. When in doupt check it out.. It has been found every where.. I do have people asking if I tested Tommy.. Not likely but could show up..

Totally agree!

Bluejay wrote:

7 True.. When in doupt check it out.. It has been found every where.. I do have people asking if I tested Tommy.. Not likely but could show up..

Tommy is a minimal overo... however looks to carry splash rather than frame... However the little bit of splash could be hiding a little bit of frame LOL

Paints eh? hah!

However indeed, OWLS is carried in the frame overo pattern, and only the frame overo pattern, The problem is, people call them all "overo's", when really they are frame, splash, or sabino, or a combination of them. Many times a tobiano is actually a tovero, but there is so much tobi going on that you dont see the "overo" at work. That doesn't just go for tobi's, it all of the patterns... You never really know what other patterns they could be carrying. Therefore, I test all paint mares before breeding. I also would test an AQHA or TB mare for it, if I plan to cross on a OWLS positive stud.

I think we should just blame all this stuff like HYPP and OLWS on Three Bars.....

Ok kido, (Merikle)... You are a smart one when it comes to all this.. You do study the stuff and it is interesting what you have to say about it.. But, please remember it is OLWS..... I had to drill my head to get it right and so do you. I still look it up to make sure this is correct..

Why was I thinking it was O-W-L-S.... HA! Okay, it's O-L-W-S...

Tell ya weird one... remember my paint stud, definitely frame overo... and they say the Robin Boys really throw that lethal gene... so I bred Rocky to Lady... Lady wasn't a frame, by no means. She was an own daughter of Sonny's Luckychance, sabino out the hoo-hah, and she was out of a quarter mare... in fact, Sonny's Luckychance was a crop-out!!!!!

First lethal we had, we took it down to oh, whatever it's called, that was doing a study on them, took Rocky, Lady and the baby. They pulled blood on both parents, told me it wasn't just the mare, it had to be both... that was the first I knew of that... they tried to save the baby, and it was the most gorgeous filly I've ever seen - absolutely perfect... but couldn't.

Had another one down the road oh, the 4th baby, the colt, was absolutely enormous, had the vet take him and see if he could do anything with him... couldn't...

Truthfully, I still don't quite understand it. If the intestines are shut off every so often, why can't they go in there and take that part out, and then redo it.... seems simple, but apparently not...

I thought is it was too.. I looked it up to make sure I was doing it right.. And, my JMS Essential goes to back to Robin Boy.. Interesting you should mention that..

As long as one is NN for OLWS then you will not get a lethal. The reason they cannot fix the problem is that the intestinal track (rectum) is missing part of it.. Not fully developed.. But, there are lethals who have enough and do survive. Most just put them down with out having them checked. The vet can stick a finger up there and see if it's all there.. It is rare but does happen to come out a happy ending..

Paints are a crap shoot for sure..

I'd heard that some do survive, but have a pale color usually on the ears somewhere...course you kinda know something's going on when the baby gets down and stays down.

Tell ya what's funky - this mare we're breeding, she's totally white with blue eyes... she's not albino, she's WHITE!... but she's a quarter horse - bet the owners were shocked when she hit the ground!

Still, ya think these guru vets could fix that mess on the babies.

As far as Mr. Robin Boy, I had an old guy, a long time ago when I first got into the paints that told me that you didn't want to breed a Robin Boy to another horse that had a blue eye - period! I thought that was kind of funky, but apparently he knew what he was talking about - I don't know if the blue eye had anything to do with it, but he was still right...

LOL sorry bluejay... I always say it as "owls" LOL I know its olws (overo Lethal White Syndrone), just had some major brain farts LOL Thanks for correcting me.

As for lethal babies, My stud is positive for it, however since we breed him to our QH or TB mares... Whom are tested and clear of it (precaution, precaution ) we need not worry. However we had what looked to be more a sabino frame splash overo mare in this year, and I warned them again... I would test her. But they are convinced its not possible for her to carry anything but sabino... But they just don't have an eye for patterns... I see the frame, and I see the splash hidden behind the sabino. Plus her sire was a frame splash, and her dam a sabino...... So if she does carry frame, they have a 25% chance of a lethal baby. I reall hope they dont get one, so sad.

That would be a bummer to wait so long then get something you really like and have it die.. That is just not right in my book.. The testing is cheap.. I know people who do this just in case they do not fall in the 25% range. Seems that maybe APHA permotes this as does AQHA on the HYPP....

Bluejay wrote:

That would be a bummer to wait so long then get something you really like and have it die.. That is just not right in my book.. The testing is cheap.. I know people who do this just in case they do not fall in the 25% range. Seems that maybe APHA permotes this as does AQHA on the HYPP....

I know what you mean. But these people would hear nothing of it. But APHA should really put it on horses papers just like HYPP.

However in my opinion... OLWS is better than HYPP... If you get what I mean? not better... but atleast the horse doesnt live on having random attacks. Things just aren't fully there and they die young. Its sad all around, and IMO HYPP should be elimintated, and all OLWS horses need to be recorded!

People also need to understand that not just "overo's" carry OLWS. And that is APHA's responsibility to do it!