[tophorsejumper]

if u dont mind me asking, what could/would happen to a horse young or old that did indeed eat black walnut leaves or nuts?

[SpiritSaddle]

Well I think it could make them founder but possibly also kill them? More then likely make them pretty sick!

[rodeogal]

I ahve seen horses start to cough something awful just standing underneath a tree. The leaves are most toxic when they are wilted. Mosted horses don't mess with the nuts. But will eat the leaves if close enough. I have 3 more of those trees to chop down. I pick up most of the walnts and take them to our local feed store. They sell them to a company.
I have seen horses kile over after its owner put walnut bedding down. HOrse died within 2 hours. it somehow trvels up through the feet.

[tophorsejumper]

oh my how terrible!

[sugarsgal]

We just plowed down our whole back field because of the Black walnut tree's. We were also told not to plant grass for 1 year after up rooting the tree's and not to let the horses back there for at least 1 year as well. Before we refence and allow turnout back there we are going to plant tomatos, if they grow we are good to go, if the don't then we will wait longer.

[4hooves4me2]

I have one black walnut in the pasture, it has been there since horses have been on this property in 1973. The horses never bother with it. I have been more afraid of cutting it down-I was told the sawdust shavings were harder to deal with then the actual tree standing there.

[BettyBootsy]

"POISONOUS PLANTS SLIDES - BLACK WALNUT"

[BettyBootsy]

Black Walnut Effects on Horses

Published Apr 25, 2003

What do tomatoes, earthworms, and horses have in common? They are all harmed by contact with black walnut trees (Juglans nigra). Tomato plants and earthworms die if exposed to a toxic substance called juglone, which is produced by the black walnut tree. Horses can suffer acute laminitis (founder) from contact with black walnut shavings in their bedding. The agent which causes laminitis has not been identified, but may be related to juglone.
During winter, one of the most commonly used bedding materials is soft wood shavings. Unfortunately, usually around midwinter, the supply of soft wood shavings can run short, and dealers may substitute hard wood shavings. According to Dr. John Lowe, director of the Equine Research Park, if these hardwood shavings contain any black walnut (even as little as 20 percent), it can be disastrous to horses.
The following examples were taken from actual cases compiled by Dr. Lowe:
Stable 1 Black walnut shavings were used to bed down ten horses. Within 24 hours, all ten required treatment for acute laminitis.
Stable 2 A load of wood shavings containing 20 percent black walnut by weight was delivered and used as bedding. All seven horses exposed to the shavings showed signs of toxicity (including two horses that had been exposed to only 10 kg of the shavings).
Stable 3 Twenty eight of thirty two horses were treated for acute laminitis within 24 hours of their initial exposure to black walnut shavings.
Stable 4 Thirty five horses were bedded with black walnut shavings. Within 24 hours, 30 had acute laminitis.
Signs of toxicity usually occur within 12 24 hours of contact with the black walnut shavings. Affected horses show an increase in temperature, pulse, and respiratory rate that corresponds to the severity of the laminitis. The legs are often edematous (swollen) from the knee or hock down. The severity of the signs ranges from slightly swollen legs to animals that refuse to move. In some horses, the hind legs are more affected than the front, giving these horses a gait that resembles myositis or "tying up." Foals and yearlings are often unaffected or recover quickly. If horses are treated for laminitis as soon as the first signs are observed, most will recover without any lasting effects.
Outbreaks of black walnut poisoning have affected 37 100 percent of the horses exposed. This variation is probably due to many factors, including length of exposure, amount and toxicity of the compound present, percentage of black walnut in the shavings, and type of storage (exposure of the cut shavings to air seems to decrease toxicity).
Horses exposed to living black walnut have also been adversely affected. Two farms in the Midwest had to take the drastic action of cutting down all the walnut trees, removing the stumps and then replacing the soil in paddocks and stables, after the development of acute laminitis and respiratory disorders in their animals. The owners and the loggers who cut down the trees also suffered respiratory disorders. The reactions to the living trees seem to be allergic in nature, and may not affect all horses or all people. Black walnut trees are among the most beautiful and valuable trees in our forests. However, those considering planting black walnut trees, especially around horse pastures, should also be aware of potential problems. Horse owners and stable managers should inquire as to the composition and source of shavings used for bedding.

[sugarsgal]

Another site that gives a great description of the Black Walnut and effects

45. BLACK WALNUT