Re: RC: black walnuts

[DreamWeaver <karen@chaton.gardnerville.nv.us>]

At 11:19 PM 6/27/99 -0700, guest@endurance.net wrote:
>wendy lumbert wendyl@jps.net
>Is there anyone out there that absolutely knows FOR SURE the effects of
>black walnut and english  walnut trees on horses?


http://www.vet.purdue.edu/depts/addl/toxic/plant45.htm

45. BLACK WALNUT
Juglans nigra
(walnut family)
TOXICITY RATING: Moderately toxic, depending upon length of exposure.
ANIMALS AFFECTED: Horses, dogs, possibly other animals.
CLASS OF SIGNS: Laminitis, breathing problems, gastroenteritis.
PLANT DESCRIPTION: These familiar trees are recent additions to the list of 
poisonous plants. Little information is yet available about their toxicity. 
Black walnuts are large (60-80 foot) forest trees often
planted as ornamentals. The bark has characteristic broad, round ridges. 
The leaves are alternate, pinnately compound, 1 to 2 feet long, with 13 to 
23 sharply toothed, tapered-pointed leaflets (fig. 45). Often there is no 
terminal leaflet. The fruit is a very rough nut enclosed within a clammy 
glandular husk, 2 to 4 inches in diameter (fig. 45A).
SIGNS: Horses are most often affected. When horses are bedded on wood 
shavings containing more than about 20% of black walnut shavings (which 
tend to be dark in color), clinical signs of laminitis (inflammation of the 
laminae in the hoof) can occur within 12 to 18 hours of contact, but 24 
hours may elapse before signs manifest. Consumption of the shavings may 
cause signs of laminitis as well as mild colic. Affected horses become 
unwilling to move or have their feet picked up, are depressed, may exhibit 
limb edema and signs of laminitis. Difficulty in breathing (increased rate 
and depth) may be noted. Horses on pasture may show mild respiratory signs 
from pollen or fallen leaves. Poisoning in dogs is reported occasionally 
when the seed hulls are consumed, causing stomach upset and diarrhea 
(gastroenteritis).
The toxin causing equine laminitis has not been clearly identified. It was 
once thought to be juglone, but this is not believed to be the toxin. 
Juglone is produced by the tree which limits the growth of other plants in 
the vicinity. Walnuts are also lethal to earthworms.
FIRST AID: Remove black walnut shavings immediately; cooling the hooves and 
legs with a hose can help. Call a veterinarian if signs are severe or if 
shavings were consumed. Prompt removal of shavings typically results in 
complete recovery. Respiratory signs in horses usually do not require 
treatment unless severe or long-lasting. Stomach upset in dogs will resolve 
when hulls are no longer eaten.
SAFETY IN PREPARED FEEDS: Reports are not clear concerning the safety of 
black walnut leaves in processed feeds. The bark and seed hulls are toxic, 
and these should never be incorporated into any feeds. In the interest of 
safety, any part of the black walnut plant should not be allowed to 
contaminate feeds.
PREVENTION: Do not use shavings containing black walnut, limit access of 
horses to pastures with walnut trees. Purchase bedding shavings only from 
reputable dealers. Do not let dogs eat walnut hulls.





Happy Trails,

Karen
in NV
& Weaver, 2,880 miles
& Rocky, 1,595 :+)
www.greatbasin.net/~sportssaddle


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