LWO question

[MountainMeadows]

Hi Guys,

I need a clarification on the term LWO. I am assuming that it stands for Lethal White OVERO - please correct me if I am wrong.

Does that mean that a horse that is a tobiano canNOT carry this gene? I am under the impression that the only time this gene can present itself is if the parent carries the Overo gene - and I do understand that sometimes our horses' colors are misinterpreted.

I guess I am wondering if I should test all my pintos (who are 99% tobiano by the looks of them) for the LWO gene since it is also my understanding that LWO x LWO can result in a dead foal. I have been crossing my pintos together for years without any problems, but maybe I have just been lucky.

Thanks muchly

Stacy

 

[h2t99]

If you have any with white on their heads or blue eyes then they carry the overo gene. A true tobiano has no white on their heads and do not have blue eyes!! So if any of your mares or stallions have that then I would get them tested to be safe. Even any that are not pintos and have white on their heads, I have been told they carry the gene, and I have had that happen when I bred 2 solids and got a loud pinto!!

 

[Becky]

Any tobiano 'appearing' horse could also be carrying LWO. LWO will normally put some kind of white on the face but not always. So the best thing to do is at least test your stallions, that way if they are negative any mare can be bred to them safely. And if they are positive, then test your mares to make sure you are not making a LWO to LWO cross.

 

[Songcatcher]

Hi Guys,

I need a clarification on the term LWO. I am assuming that it stands for Lethal White OVERO - please correct me if I am wrong.

Does that mean that a horse that is a tobiano canNOT carry this gene? I am under the impression that the only time this gene can present itself is if the parent carries the Overo gene - and I do understand that sometimes our horses' colors are misinterpreted.

I guess I am wondering if I should test all my pintos (who are 99% tobiano by the looks of them) for the LWO gene since it is also my understanding that LWO x LWO can result in a dead foal. I have been crossing my pintos together for years without any problems, but maybe I have just been lucky.

Thanks muchly

Stacy

You are correct. LWO = Lethal White Overo. In my opinion, the term "Frame" would be less confusing as several other patterns are also refered to as "Overo" but are not lethal.

Horses can carry any combination of genes, including being homozygous for Tobiano and also carrying Frame as well as other patterns. Being homozygous for one gene does not prevent the presence of other patterns.

I personally will not breed horses unless at least one of them has been tested negative for LWO. Having a LWO positive stallion, I test all the mares I plan to breed to him. The Frame or LWO gene can be carried without being obvious visually, as indicated by the stallion pictured below who is positive for Frame/LWO.

 

[Becky]

If you have any with white on their heads or blue eyes then they carry the overo gene. A true tobiano has no white on their heads and do not have blue eyes!! So if any of your mares or stallions have that then I would get them tested to be safe. Even any that are not pintos and have white on their heads, I have been told they carry the gene, and I have had that happen when I bred 2 solids and got a loud pinto!!

Yes and no. LWO normally puts white on the face but so do sabino and splashed white. Neither of those have any lethal genes associated with them and are entirely separate from LWO.

 

[targetsmom]

If you have any solid color minis with Rowdy breeding (or even without) that have white on their faces, they could very well be LWO+ too. I know someone who bred a solid Rowdy-bred mare to a tobiano-appearing stallion (also Rowdy bred) and they found out the hard way what the L in LWO meant. I also know of a solid color stallion with a blaze face who is LWO+ (more Rowdy breeding) something like the one pictured above.

As others said, if you just test your stallions and they are all negative, then you are all set. Or if any are LWO+ then you only need to test the mares that will be bred to him.

 

[Dona]

As others have said....yes, LWO stands for "lethal white overo". But....there is only ONE type of Overo pattern that is associated with the lethal gene...which is the "Frame" pattern. Splash or Sabino are also considered Overo patterns, but neither of them carry the LWO gene by themselves. They, of course, could "look" like a Splash or Sabino, but also carry the Frame (LWO) gene as well.

It is always wise to test....as pintos often carry multiple patterns, and the "Frame" pattern doesn't always show visually. I've even seen a completely solid black miniature (no visual white markings on him at all) who tested positive for LWO.

Testing is the only way to be sure!

 

[love_casper]

Hi Guys,

I need a clarification on the term LWO. I am assuming that it stands for Lethal White OVERO - please correct me if I am wrong.

Does that mean that a horse that is a tobiano canNOT carry this gene? I am under the impression that the only time this gene can present itself is if the parent carries the Overo gene - and I do understand that sometimes our horses' colors are misinterpreted.

I guess I am wondering if I should test all my pintos (who are 99% tobiano by the looks of them) for the LWO gene since it is also my understanding that LWO x LWO can result in a dead foal. I have been crossing my pintos together for years without any problems, but maybe I have just been lucky.

Thanks muchly

Stacy

LWO is Lethal White Overo, in other words the frame gene. Tobianos can (and most often do) carry other pinto patterns as well, including frame. Actually, a horse could be homozygous tobiano, homozygous sabino, homozygous splash, and have a frame gene. The pinto genes are not interelated at all, completely separate. The presence of one says nothing about the presence of the others.

So first, I would get your stallions tested. If all of them are negative, you have nothing to worry about because LWO is only lethal in homozygous form. If any of them are positive....

I wouldn't test all the pintos. I'd test every mare you plan to breed to him. The reason for this being that frame (or any of the pinto genes for that matter) can be present in the most minimal of forms. What some consider "normal face white" or "normal leg white" is really some form of pinto, and on the off-chance that it's frame, I would test them all just to be safe. Also, tobiano does not and can not cause face white, so if you have a visual tobiano but does not have a completely solid head, you can be sure there are other genes going on. Or, if you have an otherwise solid horse with face white, you know tobiano is not causing it. And I have seen a stallion who appeared just tobiano, had the white over his back, and no other marking at all and a solid head, turn out to be positive for LWO.

 

[lotsofspots]

This may be a dumb question, but what about appaloosas ... can they carry the LWO gene? ....I assume they can if they have pinto in the background? But, if so, how far back in the pedigree?

 

[MountainMeadows]

Thanks for all the feedback everyone - makes sense to test the boys, so will get that done promtly just to make sure and then it will be on to some of the mares to see if any of them carry the gene. I have very few horses with face markings, but I just had a colt who has a nice little strip & snip, & 4 socks out of two horses with solid faces, so hence the question.

Again, thank you very much,

Stacy

 

[minimule]

My boy is LWO+. We would have never even thought about it had his dam not had a lethal foal when bred to an overo. To be completely safe......test the boys!

This is Tommy's ONLY white.

 

[maestoso]

Something else to consider..... Many pintos carry more then one color pattern, so as many have said before, looks can be deceiving. Also not every Overo carries LWO, only the Frame gene carries it. BUT, the Frame pattern can be hidden among other patterns. The only safe way to avoid it is to test for it.

 

[love_casper]

This may be a dumb question, but what about appaloosas ... can they carry the LWO gene? ....I assume they can if they have pinto in the background? But, if so, how far back in the pedigree?

To answer this question, yes. ALL white markings like face white and leg markings are caused by one of the pinto genes, regardless of whether the horse is an appy or not. With the die hard appy breeders, they'll deny this because it's absolutely awful to think THEIR appies have ANY pinto in them.

OH! There doesn't have to be any noticeable "pintos" in the horse's pedigree, because 9 times outta ten, it is minimal enough to not be marked down. So appies most definitely can carry LWO, and a lot of them do, if not many of them sabino. Hmmm, I'll PM you the link to a thread about that topic, lots to be said.