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  1. #1
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    Default What could have caused this foals death?

    A friend of mine told me that one of her mares slipped her foal after 7 months gestation. As terrible as that is what was interesting to me was the foal was pure white. I know many will say Lethal White Syndrome but neither the mare or the stallion were paints of any sort. The mare is a sorrel TB and the sire is a dark bay Oldenburg. Neither have any paints in their lineage so what else could this have been. Is the fact that the foal was white even a factor in its death? I don't know but it sure got me thinking. I have no more data other than this mare has had several healthy foals and this stallion has no known history of issues with his offspring.



  2. #2
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    "Pure white" might well have been Dominant White, and if that's the case, would not have been the cause of his death. DW is not lethal in the hetero state, and is only theorized to be embryonic lethal in the homozygous state, meaning her pregnancy would have have "taken".

    It's also possible he was a maximally expressed Sabino, but that is also not cause for death.
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  3. #3
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    What are the chances of a white foal out of a sorrel and bay cross? Not a color expert here it just seems so unlikely and such a coincidence that the foal was an odd color for that cross and aborted or slipped early.



  4. #4
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    Genetic gurus: I thought I read somewhere recently that true albinism (albino) in horses has never been documented. But could that have possibly been the case here, and maybe why the foal was not carried to term?

    As for your question about a white foal, OP, it is technically possible, no matter what dominate color the parents are. If one or the other carries the sabino gene (which is what's responsible for certain kinds of white markings), and they passed it on to the foal, the gene could have theoretically been maximally expressed, as JB said. Meaning that instead of just a white face and/or some stockings, the foal is white all over. But again, this would not have been a cause of death, it is simply a coloring pattern.
    "...That's the worst, I think. When the secret stays locked within not for want of a teller, but for want of an understanding ear." --Stephen King



  5. #5

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    They do not have to be paints to carry the lethal white gene.



  6. #6
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    Oct. 25, 2010
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    Default

    Thanks for the information. What other factors can cause the lethal white if not overo paint? By paint I mean not just the breed but the color splashed horse of any breed.



  7. #7
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    Default

    JB - could this have been a lethal homozygous DW death? Or are those deaths early on in the pregancy, and are reabsorbed rather than aborted.



  8. #8
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    Default

    I have heard of this in a thoroughbred before. Mare aborted white foal late term. No obvious sabinos or overos in pedigree.

    http://www.horsetesting.com/LWO.htm
    I don't know if this foal would have been a lethal white. According to this link they die after they are born.



  9. #9
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    Quote Originally Posted by Kerole View Post
    JB - could this have been a lethal homozygous DW death? Or are those deaths early on in the pregancy, and are reabsorbed rather than aborted.
    From what I understand, the pregnancy almost just doesn't happen. The embryo does not implant.



  10. #10
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    Overo lethal white is lethal after birth. The foal will appear normal at birth but due to an incomplete digestive tract it dies of colic within a few days. Until the digestive tract is functioning (after birth, eating) the pregnancy should continue without problem.

    With the homozygous DW, I assumed it was similar to the double roan. The embryo just does not develop. Loss is very early if pregnancy is detected at all.

    It does make you wonder though if there was some sort of mutation or other genetic factor at work and whether the white was a piece of it, or just coincidence. I think if a mare miscarried that late, I would probably dispose of the body, tend to the mare and try to move on, however if it came out white or with other visible red flags, I might have to do genetic testing or necropsy to try to avoid it in the future.
    The rebel in the grey shirt



  11. #11
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    I would think it's simply coincidental and there is a DW gene in there (sounds like this mare wasn't tested...especially since TBs are registered chestnut and sorrel is not a recognized color), but I would also have a genetic test done. So many things can happen to cause a mare to abort, but the white would make me look deeper.
    "IT'S NOT THE MOUNTAIN WE CONQUER, BUT OURSELVES." SIR EDMUND HILLARYMember of the "Someone Special To Me Serves In The Military" Clique



  12. #12
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    She is a registered TB I always thought sorrel meant bright red color and chestnut was more a brownish red. I don't know if any testing was done and can't see any reasons before this happened to want to test for anything. What factors would make a breeder feel the need to test a mares genetics and for what issues would you test for?



  13. #13
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    Derby Lyn- What were the factors in the white foal you know of?



  14. #14
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    It's just a pet peeve of mine. The Jockey Club doesn't recognize sorrel as a color, all reds are registered chestnut. Really, sorrel is only wholly accepted in the stock breeds (QH, Paints, and the like). But that's not the point.

    I don't know that there would've been any reason to test the mare before this because there was likely no reason to. But with this foal? I definitely would. Both on the foal, and on the mare. I'd feel better ruling out some weird genetic thing than just assuming it was a fluke.
    "IT'S NOT THE MOUNTAIN WE CONQUER, BUT OURSELVES." SIR EDMUND HILLARYMember of the "Someone Special To Me Serves In The Military" Clique


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  15. #15
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    Right, LWO is born a live, active foal, then dies - nothing about it causes death in utero.

    DW/DW never achieves a detectable pregnancy.

    It's unlikely this is was a max Sabino foal, though not totally impossible. It's the SB1/SB1 case which expresses 95% or more white. But, TBs don't have SB1. However, though there are other SB genes "known" to be out there, none other are testable at this point. It's possible that another homozgyous state can create a max expression.

    TBs are fairly notorious at this point for new mutations of DW, and when it's a new one, it's usually all white. Other breeds do this - Kerole has an all white Hano mare who is a new DW mutation.

    I do think color is not a factor for this foal - 7 months seems to be that magic time where they make it or they don't - so many threads here every year about 7-8 month abortions
    ______________________________
    The CoTH CYA - please consult w/your veterinarian under any and all circumstances. - ET



  16. #16
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    Quote Originally Posted by JWB View Post
    With the homozygous DW, I assumed it was similar to the double roan. The embryo just does not develop. Loss is very early if pregnancy is detected at all.
    Yep, But, just as an aside, there are at least 3 Roan mutations, and only 1 of them is homozygous embryonic lethal
    ______________________________
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  17. #17
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    Lepto, rhino, knot in the umbilical cord, high fever in the dam, the possibilities are endless and most likely have nothing to do with the foal's color. I am sorry for the loss. Been there, done that unfortunately. Most of the time you have no idea why even with a necropsy.



  18. #18
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    I agree with JB. This death probably has little to do with color.

    7 months seems to be the "abort time" for an abnormal foal or about some gestational abnormality (even twinning, where other twin may have been resorbed, but the uterine environment was contaminated for the remaining foal -- and you'll never find it).

    Did your friend have a culture and cytology done on the dam post abortion? That may tell the tale.

    It's always important to remember that often "nature" dispels that which cannot survive well, so that can be a blessing.

    Always so sad to lose a foal so close to term.



  19. #19
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    I'm actually going to disagree with the others. IMO to have a still born that just by chance ALSO happened to be white from parents who give no indication that should have been possible... that just can't be coincidence IMO. Either one of those things happening is a slim chance, but happening together, the odds are astronomical.

    The gene that causes dominant white (and also roan) is constantly mutating. We don't know of a case that it causes a stillborn white foal... yet. With it's constant mutations and it's strong predisposition to being a problem when it's homozygous it's very possible a new mutation could crop up that would cause exactly this. However that would require that both parents carry a DW mutation at all and might even require them be the same mutation which is extremely unlikely in this case.

    Chances are this was a mutation in this foal, not one of the parents.

    By far the most likely scenario here is something just like this:

    A new dominant white allele was suspected when two Thoroughbred horses with minimal white marking on the coat produced a colt with a large amount of coat depigmentation. Because of its association with similar patterns in other horses, the KIT gene was selected as a candidate gene, and all 21 exons were sequenced in the colt. A novel 5-bp deletion was discovered in exon 3 and was confirmed with allele-specific PCR.
    Unfortunately, around 5 weeks of age the colt was found dead in his stall. The body was sent to the University of Kentucky Livestock Disease Diagnostic Center. Necropsy found mild focal suppurative bacterial omphalitis, severe chronic gastric ulceration and mild multifocal hepatitis. The death was attributed to cardiovascular shock and ventricular arrhythmia of undetermined aetiology.

    Gastric ulcers have been documented for some human and mouse KIT mutants (Kitamura & Hirotab 2004). No similar cardiovascular defects were documented for murine allele variants (Bult et al. 2008). It is possible that the exon 14 polymorphism only has a mild effect on phenotype that is not usually detected; there were no detrimental effects reported in the original study documenting this allele (Haase et al. 2009b). However, if the mutation was present in the non-truncated copy of KIT, thus making the colt a compound heterozygote, the receptor’s function may have been affected enough to cause detrimental effects that could have contributed to the foal’s death. Unfortunately, as only limited tissue samples were available from the colt, it cannot be concluded with certainty that effects of the exon 3 deletion in KIT contributed to his death.
    If that ^ can happen, there is no reason to believe that a term white foal with even greater health problems couldn't come of a de novo KIT mutation.

    ACC


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  20. #20
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    In breeding anything is possible...and sometimes, we will never know, despite the diagonstics or necropsy. That's so unfortunate



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