Maple Trees

[tuppysmom]

Are all Maple trees toxic to horses? Are some OK? If so, which ones. Thanks!

[RiverBendPol]

No. So called Red Maple http://en.wikipedia.org/wiki/Acer_rubrum is the toxic one. At the bottom of this article it states that 1.5 pounds of leaves can cause illness-My vet has seen death in a horse with a MUCH smaller ingestion. She also says the leaves are not toxic until they begin to wilt and die. Scary.

[DiablosHalo]

There have been studies on the Silver Maple as well- but inconclusive results (meaning I know about the study but can't find results of such study!).

I've heard of a very low tolerance for Red Maple once leaves wilt.

[dmalbone]

Actually, most of them are safe except for Acer Rubrum, the typical red maple. Our horse pastures have been lined for 10 years with full sized silver and sugar maples and they're fine. Fatten up in the fall from the leaves... but fine. :lol: I did just move and have Japanese maples which are physically red, but have yet to find out whether these are dangerous or not.

[tuppysmom]

We seem to have silver, and sensation maples.

[talloaks]

Cherry trees, at least wild cherry trees, have the same toxic properties when the leaves are wilting.

[Erin Pittman]

Cherry trees, at least wild cherry trees, have the same toxic properties when the leaves are wilting.

It's actually a different toxic principle in cherry trees (and all members of the prunus species, including apricots, peaches and plums). When the leaves wilt, they release a cyanogenic glycoside called prunasin. When those reach the cecum/large intestine, they are converted to free cyanide and the animal dies of cyanide poisoning. The cyanide blocks the ability of hemoglobin to release oxygen so the animal's tissues basically become starved of oxygen. Because of the way horses digestive tracts are set up, they are less likely to be poisoned by wilted cherry leaves than ruminants such as cattle.

In Red maples and hybrids of red maple (and possibly silver maples, as already mentioned), the toxin, which has not yet been identified, acts much differently. The toxin in red maple oxidizes hemoglobin in red blood cells causing formation of Heinz Bodies leading to hemolytic anemia. The scary thing with maple is that the leaves are toxic when wilted or dried, and in fact they've discovered that they appear to be more toxic as the leaves get older (i.e., more toxic in fall when dried leaves fall). Horses apparently also find them pretty tasty. Only takes about 6 pounds to kill a pony in as little as 1-5 days. Horses are the only known species to be affected by maple poisoning.

[Mallard]

Here's an excellent link from the Ontario Ministry of Agriculture.
I'm in Ontario and goodness knows we have a LOT of maple trees

http://www.omafra.gov.on.ca/english/livestock/horses/facts/06-109.htm

It's only the dead, wilted, dried-up leaves of the read maple that are toxic.
And 1.5 pounds of dried up leaves is a LOT of leaves.

I have a red maple bordering my pasture and I have never, ever seen my horses show ANY interest in the leaves, dead or alive.

[blaster]

I have a red maple bordering my pasture and I have never, ever seen my horses show ANY interest in the leaves, dead or alive.

Ditto here.