Friday, January 15, 2010

On the wings of an Angel

Lisa at Laughing Orca Ranch asked in the comments of my last post what "OLWS," after Angel's name, stood for. Rather than bury my response in the comments, I thought I'd tell Angel's story, then get out my soap box and rant a bit.
"Overo Lethal White Syndrome" is a genetic anomaly that research indicates results from a foal being homozygous for the frame overo gene (got one copy of the gene from both sire and dam). Besides usually being all white (sometimes a bit of color on their ears), they are often deaf, and their large intestine is either incomplete or grossly underdeveloped. As soon as they are born, OLWS foals begin to show signs of colic, as there is no place for anything to go in their digestive tract.

Because she is a gray, it's hard to see Misty's classic frame overo markings except in her thin summer coat, but she has fairly large belly spots and a few lightening bolts on her neck and shoulders, as well as an apron face on one side--you can see the edge between black "flea-bitten" and white marking, just below her eye in this photo.
(She would be black except for the gray gene--born black, as was our first foal Eddie, who is also nearly white now at age ten. We believe the black spot on her neck, and a few others she has, is a Bend Or spot--but that's another story.)

The third time we bred Misty it was to this local Paint stallion, Max Tardy, also a frame overo.
Max is striking enough that his photo is on the front of a Western Horseman book about legendary Paints:
It's those irregular, flashy overo markings that I personally prefer, over tobiano.

The resulting colt, Dodger, was solid black, except for his blaze. He likely didn't get the overo gene from either parent (being a dominant gene, overo can't "hide" for a generation, although it can be minimally expressed in, say, a wide blaze and high white stockings--that's how a "crop-out" overo shows up from two solid Quarter Horses).If you remember anything about basic Mendelian genetics from high school biology class, you may know that the odds of getting a particular gene are:

25% no gene, solid
50% one copy (from either the dam or the sire), overo
25% two copies (one each from both the dam and the sire), homozygous/lethal white

heterozygous parents

O (overo)

N (non-overo)

O (overo)

O/O (lethal)

O/N (overo)

N (non-overo)

O/N (overo)

N/N (solid)

Dodger was built so nice, and had such a nice personality, that we bred back to Max again. (At this point we had had three boys in a row, and I was trying for a filly to be the replacement for Misty, who was by this time 15 years old, and nearing the end of her breeding career.)

But I wasn't aware of the risk we were taking...
I must admit to not having educated myself adequately to the dangers of breeding overo to overo. But I also blame the stallion owner for not educating me--turns out she knew her stud carried the OLWS gene, and should have been able to counsel me that Misty probably did as well.

In the spring of 2004, we were ready for foaling. Misty went into labor, but was having some difficulty. She cast herself twice in the stall, so I finally just let her out into the paddock. Even there she wasn't making any progress--we had "two toes and a nose" but, after a half hour, nothing more, even with a few gentle tugs on those front feet. Allan was on the phone with the vet, relaying instructions, and I had my coat off and my sleeves pushed up, ready to reach inside the birth canal to see if there was something hung up, when Misty started another contraction. One does not want to be inside during that muscular effort, so the vet had me try pulling just a little more firmly on the foal's pasterns, and by golly, we got a baby!

She was strong! [Yes, she was the filly I had been waiting for.] She was on her feet faster than any other foal we've delivered!There is such a thing as an all white horse, but I knew in my heart that the filly wasn't going to make it, as soon as I saw her color.

I pushed her gently back up the slope to the barn, with Misty following behind.The filly nursed quickly and well, but it just exacerbated the bellyache she already was showing signs of: At first it almost seemed "cute" to see her lay down and roll, over and over again --until you realized that it was an effort to escape the pain.In between, she would rest.I sat with them all night, though there was not much I could do to make the filly comfortable. I took them in to the vet, first thing the next morning, and he tried a couple of things [enema, mineral oil tubing], but he found no evidence of it simply being a meconium impaction. We ended up putting her down before she was a day old. Necropsy showed the last several feet of her intestine to be no bigger around than your little finger.

The story of how she got her name is touching:
Knowing I would most likely lose her, I hadn't given the filly a name at all.
After the vet worked with her a while first thing in the morning, he got busy with his day's regular schedule, and, other than checking on her quickly from time to time, he did not have the time to euthanize her until late in the afternoon. I stayed with her and Misty in the outside pen most of the day, even though it was a chilly, blustery day, and in my rush to get to the clinic early, I had not dressed very adequately. So, just once, in the afternoon, I went inside the waiting room to warm up with a cup of coffee that was offered. During those few minutes inside, a neatly dressed man came in and asked if he could post a flyer on their bulletin board. When the receptionist inquired about what it was for, the man identified himself as the interim pastor of a local church, and said that the church was having a "blessing of the animals" that Sunday, in honor of St. Francis of Assisi, the patron saint of animals.
It seemed that he had been sent to the vet's at that very moment for a reason.
I asked if he would be willing to come out back and bless one small horse that wouldn't be around until Sunday, and he immediately agreed.
As we walked towards the pen, he asked what the filly's name was. With absolutely no previous thought on the subject, I blurted out "Angel"--it just seemed so appropriate for the snow white filly that would too soon be running, pain free, in Heaven.
The pastor blessed her, and prayed with me for a quiet passing.
Not ten minutes later, Dr. Mark came out, ready to put little Angel to sleep. He asked if I wanted to be there, and I replied "Of course." We led Misty out to the trailer, so her calling wouldn't alarm Angel. But the fact was that Angel was too weak at this point to fuss much. And as much as Misty carried on as she was led away, Angel didn't respond (this is why I believe she was, in fact, deaf).
I held the filly in my lap while Dr. administered the euthanasia drugs. And then she was gone.
Such a beautiful, strong filly didn't deserve such a short, pain-filled life.

OLWS is the APHA's "nasty little secret."

It is not a genetic "disease" in the sense of HYPP or HERDA or CID. But it is a genetic flaw.

A flaw that is always fatal!

It is possible to test for the presence of the overo gene, so therefore the flaw is predictable.

And, because it is predictable, it is PREVENTABLE!

APHA chooses to bury it's head in the sand. They did start one study of the prevalence of OLWS foals, but, as far as I know, it was never made public. You can find a small bit of discussion on their website, if you know where to look. But they do not require breeding stallions to be tested, nor do they require stud owners to report if their stallion carries the gene. Most folks don't advertise that their stud carries it, but will tell you if you ask (they are starting to advertise if the stud doesn't have it).

Some big time overo breeders say they are willing to take the risk, one going so far as to say that losing a few foals is worth the high quality foals that they get otherwise! (For me, one foal was 100% of my foal crop for the year--hardly economically efficient...not to mention the emotional toll on Misty and myself.)

There are those who say the 25% figure is false, that there are not nearly so many OLWS foals born. But the fact is, no one really knows--they obviously never get registered, and no effort (beyond the one study) has been made to actually get an accurate tally. And there are many other factors that play a part: two other overo sub-types [sabino and splash] are not tied to that specific gene, and, because the genetic differences between the three sub-types has only been established in the last few decades, it is not always the case that an "overo" carries the flaw. Some mares that fail to carry their foal to term, may have actually resorbed a non-viable fetus.

Maddie is Misty's daughter, by a tobiano stallion. Visually, she would appear to be a classic tobiano........except for her apron face on one side--an overo characteristic.

I planned to use her as a broodmare some day (the replacement for her mother), so I had her tested. She is technically a "tovero", carrying both the tobiano and frame overo genes. I will never breed her to an overo stud unless he has been tested negative for the OLWS gene (in which case he would have to be either splash or sabino).

Jackson is Maddie's full brother, and his wide blaze and more irregular spotting pattern tells me he may very well be tovero as well, though APHA registered him as Tobiano.Because he will be gelded this spring, I will not have him tested nor argue with APHA on the classification.

Kate is by Angel's sire, Max Tardy, but out of Zoey, a breeding stock dun with nothing but tobiano in her pedigree.But Kate, too, carries the lethal frame overo gene, inherited from her sire, and will never be bred to any stallion that has not tested negative for the gene.


  1. What a sad story because of someone's ignoramous greed to breed their stallion. THEY SHOULD HAVE TOLD YOU! Gosh, I had to take a break in reading your story, because the tears were so much, I could not see. How Sad for Angel. Through all this you have learned a lot. A very hard lesson to learn though, and it breaks my heart. I can't imagine what you went through. Thank you for sharing, and I now know a lot more than I did.

  2. I only learned about OLWS about a year ago, when Kerstin (our vet) was late for a routine call because of the birth of an OLWS foal that resulted in her euthanizing both baby and mum. It is similar to results of merle-to-merle breedings in dogs, where 1/4 of the pups will be pattern white (mostly white with small colored patches) and there is a high probability of hearing and/or vision problems.

  3. That's heartbreaking. When I saw you had an OWLS baby, I figured you didn't know beforehand. :( There's a less severe human variant of the condition, too - the nerves in the intestines don't develop correctly.

    I'm glad to hear Angel will be your only OWLS foal. It's heartbreaking that some breeders don't care to test for it, or roll the dice anyway. Thanks for sharing her story.

  4. Kate is gorgeous!

    Thanks for explaining what happened to sweet little Angel. What an amazing, heart touching story at the end of her short life, too.

    How sad that it had to end so soon..


  5. Such a sad story - shame on the people who don't test and don't tell, and on the breed association for doing nothing about it. We have an overo pony, Norman - very flashy champagne dude - but he's gelded so no breeding for him.

  6. Thanks everyone, for your concern and support. It was a very tough situation.

    mrscravitz--Yes, the stallion owner should have said something. And the APHA should do much more in the way of education. But I also blame myself for not doing MY "homework"--I now know much more about the genetics of color than I ever would have thought--but I should have educated myself before I started breeding, not after this problem reared it's head. Sorry to make you cry.

    dp--Yes, I've always loved merles, but had heard of the similarity. Are the pattern whites white around their ears? I wonder if their deafness is similar to the deafness found in white-faced Paints (the famous Gunner and his bald-faced offspring, and my friend's overo mare Helen)? The theory is that the lack of pigment extends into the ear canal and affects the functionality of the cilia (?) that help transmit sound vibration to the brain.

    Funder--I have to admit I DID know a little, but not enough. And no more breedings will ever happen on my farm that take the risk. And, should I sell either Maddie (a possibility) or Kate (much less likely), the buyer will be strongly warned.

    LOR--Yes, I'm partial to Kate, as well: the overo I like, overlaid on her mama's striking dun coloration--the ultimate in back-yard color breeding! But she's also got a great personality and workmanlike (if chunky) conformation.

    Kate-- Shame is a good word for the purposeful breeding of overo to overo. And I've seen your photos of Norman, both in show shape and in retirement at Paradigm--What a cutie!

    Thank you all, again, for your comments.

  7. This is a heartbreaking post, EvenSong, but so important, and very beautifully told. Every person that learns about OLWS and about Merle to Merle breeding, is one more to spread the word, and eventually either force disreputable breeders to clean up their act, or better still, spur them on to another source of income, one that doesn't involve animals. It was heartbreaking to read; I felt your pain as you sat through the night and a good part of the next day with your poor little foal. Thank you for sharing that story with your readers.

  8. I just so happened to come across your story while i was googling max tardy. Crazy enough he is my mares sire. She too had a 25% chance of being a lethal white, but i was not aware of this until i looked up who her dam and sire each were when i was looking to breed her (after learning of the lethal white i bred to a tobiano). It was terrifying to think that she had a larger chance to be a lethal white than what she actually is (a solid sorrel with just a white face). But, heres some good news, he was sold in 2005 to a new family. We now have one less person to watch out for in keeping important information that lead to devistating situations. I hope all you future babies are healthy and im sorry for your loss.

  9. Kristy--Thanks for visiting! Yes I knew Max moved to California, but they haven't updated their website or FaceBook since 2009, so I'm not sure what he's up to these days. Sounds like you are here in WA?
    I still have one of my three Max babies, and she's a real winner--Kate on the blog. I've really liked all of them! Fell free to visit again!

  10. Yes I am from WA as well! Pretty close to you actually! I recognize the hills in the background of your other blog! Im about 20miles from Yakima.