to clarify, though, even solids and tobianos can be lw carriers, and thus must be tested negative before being bred to another carrier. You breed two carriers together, regardless of their base color or apparent pattern, and you've got one if four odds of a lethal foal....and it's true that no vet can save them. they colic and die or you euthanize them. The gastrointestinal tract is malformed and incomplete, as the same gene that controls the color also has a role in gi development.
You want to find out yourself but this is for anyone else who may be reading for their own information.
Lethal white IS the frame gene. Not all overos have it (splash and sabino are overo genes too). A horse that appears frame is not necessarily such, as sabino and splash can and do appear in the same horse, and they clash to create patterns that LOOK like frame.
I thought my filly was negative by default of colouring but after reading this thread I think I'll have her tested if I want to breed. That being said I will probably breed her to something of a breed that doesn't have the gene simply because that is where my interest lies. Always best to be safe though and I would HATE to breed a carrier that then got bred on and had a lethal white foal.
Overo basically means "not Tobiano" so, not all overos are LWO. Frame, Splash, and Sabino are all lumped together as an overo by the APHA. Personally I prefer to drop the Overo and designate each pattern for what it is Frame, Splash, and Sabino. Each is a separate pattern and they are NOT related to each other except by virtue of not being Tobiano.
I did want to note a few things. 1)Frame can be present alone or with any of the other patterns. For example, it is possible for a horse to carry all four patterns. So just because you have a Tobiano doesn't mean it doesn't also carry Frame. Please test before breeding to an untested or Frame (LWO) positive horse. 2)Although an all white foal is most likely homozygous for Frame, it is also possible for a foal to be born all white and NOT be homozygous. Such foals should be tested (by rush order) for LWO and monitored closely but not automatically euthanized. An all white foal that is not homozygous for LWO could carry more than one pattern or be Maximum Sabino or Dominant White. 3)Unless a fence jumping is involved Arabians do not carry Frame (ie LWO).
3)Unless a fence jumping is involved Arabians do not carry Frame (ie LWO).
Because of the SCIDS, CA & LFS genes in Arabians, rather than just assume because it's a purebred it's clear, I test. That way when I have bred to an OLWS carrier, I can show a prospective buyer (who may or may not understand the whole OLWS thing) that the carrier was only bred to a 'tested clear' horse, same way I would if I had a SCIDS carrier being bred to a non-SCIDS carrier. It's a cheap test, can be run at the same time as all the other genetic testing that needs done and can bring peace of mind to a buyer. I also test the foals of a carrier horse so that I can disclose before close of sale what that horse's status will be and I send a copy of the test results with the horse. Since a lot of Arabian people know Sabino is an Overo trait but they don't understand Frame and Splash and the other pattern characteristics, I get asked if the stallion, who is not pinto or paint, carries the OLWS gene.
It's very simple--lethal white occurs when you breed a foal from a low gene pool. When it happens in the wild, the animals die and then they cannot pass on these harmful genes. It's such a shame bc it's ALL about color. I guess I just don't want to participate in producing pretty horses that die bc of bred-in genetic abnormalities. So has the purebred dog world gone, and so goes the purebred horse world.
My mare,"Warren's Cindy" (KMHSA) is a breeding stock paint, all chestnut (or...er...some color of chocolate), with one brown eye and one blue eye and has been bred 4x. She has produced 2 solid foals and 2 spotted foals, and one of the spotted foals had 2 blue eyes, as well.
I also think that you can find some very nice horses whose breeders reject them bc they come out solid...like Cindy's breeder did. (I bought her from her 2nd owner, who found value in her.)
It's very simple--lethal white occurs when you breed a foal from a low gene pool. When it happens in the wild, the animals die and then they cannot pass on these harmful genes.
The frame pattern (aka Lethal White Overo) does occur in wild (feral) horses that live and thrive. Horses with a single copy of the mutation are not affected except to the extent that they usually show a pretty white pattern. It also has nothing to do with the size of the gene pool as it occurs in many different breeds with a wide variety of genetic diversity. Affected foals can easily be avoided by testing your breeding stock and not breeding to frame to frame. As Dreamcatcher Arabians pointed out it is an inexpensive test.
Alforddm, I appreciate that. I'm not looking to offend ANYONE. I do, however notice an increase in health problems in horses that are the result of breeding to a type or a color--it's a current trend. I'm not referring to an upright shoulder, or a straight leg or a weak back, but I think "lethal" white says it all. I just don't want anybody to breed a horse (or dog) that isn't healthy bc of the genetic mix that they intentionally choose. I guess you could say that I "campaign" against this.
I have talked to a lot of horse people, many who sternly maintain that it will be okay to breed this or that, understanding that there are documented health problems, bc they've found one specimin that didn't have it. I'll tell you, one time was enough for me. Here is a picture of my QH gelding, "Dandy Silver Moon."
He was a gorgeous cremmelo, great attitude and willing. He went blind at age 7. I, for one, will not EVER buy another cremmelo. I understand it's referred to as an "Isabella Palomino," and you can make out his blaze, in contrast to a dappled, ivory coat. I was stunned when my Vet discovered his sight problem, but he told me the defect was genetic. Even IF it only happens periodically, I do not think breeding this improves these horses. Again, I am sorry to offend anyone but I get very attached to my horses, and I cannot afford to keep one crippled by a genetic defect as a pasture-pet. OP, Please consider outcrossing your mare for the color you want.
The way you're referring to Lethal white makes it sound as serious as HYPP. A horse with one copy of Frame has no issues. It's usually just a rather loudly colored horse. A horse with two copies will die, but one copy is completely harmless. HYPP will have symptoms and affect an N/H horse. A horse with one copy of HYPP shouldn't be bred at all, even to an N/N horse because there is a chance that foal will be N/H and be affected.
If you breed a OLW Positive horse to a OLW negative horse, your foal won't die of lethal white. I'm not saying it's not a serious problem, but a simple, inexpensive test will save you from breeding a dead foal.
EthanQ there digestive system doesnt develop....colon lacks nerves to send flush colon and it becomes impacted...like cholic symptoms...very painfull death.... we just baught a mare in july that apperantly was bred back to a frame she is b/w frame...i new nothing when we baught her. Now all we can do is x our fingers...not cool. Breeder didnt say a word. I found out here on the forum