-- Posted by seb1 on Oct. 1, 2001

 Are conkers poisonous to horses. I know they are a low grade toxin and, like acorns, it would be dependant on how many were eaten...... I can't find any information on them in any books, and am spending ages picking them up, only to have the wind knock 100's more out the tree!. I can't fence it, as the tree is huge, and provides the only shelter in the field. Can't move them into the other field until the fencing is completed - hopefully in 2 days time.... any one got any info on conkers and horses would be gratefully received!.... many thanks.....

-- Posted by sarjay on Oct. 1, 2001

Dalesponyrider I'm in the same predicament so I hope someone knows the answer! The huge horse chestnut(?) tree is the only shelter my girls have so can't fence it off but I am also worried that the conkers are poisonous to them.
Anyone know the answer?
Sar

-- Posted by JanetGeorge on Oct. 1, 2001

Common Name: Horse chestnut, buckeyes
Botanic Name: Aesculus species

Animals Affected: Cattle, sheep, horses, swine, chickens and humans have been poisoned naturally and experimentally by various species of buckeye.

Toxic Principle: The glycoside aesculin and fraxin and possibly a narcotic alkaloid, present in the young growing sprouts, leaves and seeds are thought to be responsible for toxicity in animals. Poisoning of livestock generally occurs when animals eat the leaves and sprouts of the buckeye as they generally leaf out before other plants in the spring. As little as 0.5% body weight of ground nuts fed to calves produced severe poisoning.

Gastrointestinal: Vomiting and abdominal pain.

Muscloskeletal: Muscle twitching, weakness and a peculiar hopping gait have been reported

Diagnosis: Hyperglycemia, glucosurea and proteinurea appear to be consistent features of severe toxicity.

Special Notes: The nectar and sap of A.. californicum is known to kill honey bees that feed on it, so much so that bee keepers recommend moving hives during the flowering period of the California buckeye. Roasting or boiling the nuts destroys the toxins.
And - as if that's not enough:

Dorsal medial strabismus to the Occular System - whatever that is!

-- Posted by cervine  on Oct. 1, 2001

Just to cause confusion, Juliette de Bairacli Levy (sorry!) who is usually utterly reliable, offers the opinion that ground-up horse chestnuts are (were) used to treat lung problems in horses, and that Spanish peasants feed horse chestnuts to all their stock including cows and horses. She says that they act as a general tonic for horse.
Having eaten horse chestnuts myself, I' m inclined to agree with Janet!!! They are mouth-puckeringly tannic. However, I doubt it would cause harm if your horses ate SOME.

-- Posted by JanetGeorge on Oct. 1, 2001

I think MOST (not all) of these things that are poisonous are dependant on the amount consumed.  After all, isn't arsenic used in minute doses to treat something or other.  And Warfarin is used to treat blood clots.

I should add I am not an expert in poisonous plants - just have a few good books and just found a very handy website : http://www.vth.colostate.edu/poisonous_plants/index.html

When I update, I'll add the link to the pasture management pages so you'll be able to find it in six months time.  It's Colarado State's site and an excellent searchable database by common name or Botanic name.