EDM in siblings

[Loudlaugh12]

Hi all,

A year ago, after a very long vet journey, I euthanized my 12-year old gelding after he developed dangerous aggression toward humans and was severely sleep deprived (as in, he never slept). I had owned him for 6 years. Prior to this, he was never quite right, did not learn as expected with training, had chronic treatment refractory ulcers and IBD, odd stall behaviors, chronic back pain, and gait issues. All the typical diagnostics were normal (no EPM, Lyme, neck and back rads were okay, etc). I did not do a necropsy.

This past week, the owner of one of his full siblings reached out to me, and as it turns out, the dam of my horse had 5 babies with multiple sires: 4 are deceased (including mine). Of the offspring, two have confirmed EDM, one has necropsy results pending but was euthanized with strong suspicion of EDM. The 5th horse is still alive but reportedly symptomatic.

The dam was just bred again, and the current owner (different than the breeder of the five aforementioned siblings) does not appear to grasp the gravity of these cases and when informed, was dismissive. As you can imagine, all the sibling owners are sad, validated, and horrified that the dam is in foal again.

We have all communicated case information to our vets and also Dr. Johnson at New Bolton, who was the vet for one of the horses.

I like to write on this forum as a way of processing things and the information I have learned in the past few days makes me deeply sad for my horse and the others. I know now that he was sick, and dying. I know I made the right choice to put him down before he seriously injured anyone or himself (and there were close calls toward the end).

There is a question among the sibling owners as to whether contacting the vet who just bred this dam with this info would have utility. Any thoughts about this?

[4horses]

If the mare is healthy I’m not sure why all her foals would be sick with EDM. It’s definitely very odd. Are the foals all being raised by the same owner/breeder and being raised in the same environment that they might be vitamin E deficient?

This is very sad but it’s certainly an odd way for a genetic disease to pass on. If the disease is dominantly inherited the mare herself should be affected. It certainly makes me wonder about a deficient diet.

[4horses]

The development of a genetic test for eNAD/EDM would have widespread impact, even if it were breed specific. Currently, the best approach to eNAD/EDM is to focus on preventing cases by providing pregnant mares and foals with access to pasture. Alternatively, dams’ diets can be supplemented with high doses of water-soluble RRR-α-tocopherol during the last trimester of gestation, with continued supplementation of foals through the first two years of life. It is important to measure horses’ baseline serum vitamin E levels prior to supplementing. While considered generally safe, oversupplementation of vitamin E is possible and can lead to coagulopathies.

[Loudlaugh12]

The dam as far as I know is not a riding horse and does have behavioral issues. But she herself is very well bred. Also, all the horses were born in a north east state, with lots of green grass.

[4horses]

And what about grand dam and grand sire?

I definitely wouldn’t be breeding that mare but what can you do? It’s not your horse. If the mare has health issues, you would think she would get worse and require euthanasia.

[barnesthenoble]

I’m so sorry for your loss, and to hear that the breeder doesn’t seem to understand the gravity of the situation. Unfortunately I’m not really sure what you can do other than make note of this yourself and share this information if you know someone who expresses interest in a foal from this breeder. Sharing the case history with Dr. Johnson and your vets so that the veterinary community can learn from it is also helpful.

Out of curiosity, would you be willing to name the bloodlines involved via PM (or publicly, but I know it can be a sensitive topic)? No worries if not.

[RedHorses]

The vet I’d be reaching out to would be the one doing the most EDM research and looking for a test. I don’t think you can contact a vet and say this mare owned by someone else is producing foals that end up with EDM and shouldn’t be bred, and expect that vet to do anything concerning a horse that isn’t yours. If the foals are registered the breed association may be interested.

[SBrentnall]

UC Davis is working on this, and has a test kit that has had some good results without having to wait for a necropsy.

[Critter]

Most of the published research is actually about genetically linked EDM in very young horses and is directly related to vitamin E deficiency. It could also be an issue with the absorption or processing of the vitamin E, which certainly could have a genetic link (if it were related to enzymes or the body’s ability to absorb and utilize the vitamin E).

My gelding that had EDM was raised in a pasture on high quality green grass…so we know it wasn’t a lack of available vitamin E in his case. However, his sire produced a few foals crops and then was gelded due to being “difficult” - though he became a YR horse in Europe right after being gelded. There aren’t a lot of foals from that stallion…so it always made me wonder if there was something not shared. The dam had about 7 or 8 other foals, and none had EDM or neuro issues.

You might want to reach out to Dr. Carrie Finno…as she has done a lot of research on EDM and also on genetics of diseases: https://vgl.ucdavis.edu/research/finno