# Cedar Toxicity – Trees in Pastures



## AngC (Jan 9, 2013)

In another thread, a member inquired about using cedar mulch as a temporary solution to a drainage/mud problem. There were a couple responses saying that cedar is toxic to horses, which immediately set my worry-machine into high gear. My track record with 4 horses in less than 2 years is: 1 dead, 1 blind, and 2 healthy (so far.) We have cedar trees in our pastures; they shed litter that is essentially mulch-like, so my optimum solution would be to immediately get rid of them all if they’re toxic. That’s easier said than done. [To stay on topic and not make this too long, I won’t write about the dead horse and the blind one and won’t write about the cedar tree problem. If somebody was interested I would write separate posts—let me know.]

Some (if not all) of the cedar trees are going to have to go at some point, but for now I had the problem on the back burner. But I figured I better research this some more in case I have to reprioritize. Researching on the internet is frustrating (right now, I’m thinking of the State Farm advertisement with the French model... “They can’t put anything on the internet if it isn’t true”)

I haven’t reached any conclusions on cedar toxicity but wanted to share a link with you and also some random “things that make you go ‘hmph?’”

I focused primarily on Thuja plicata aka western red cedar, since that’s our variety, and specifically on red cedar trees in horse pastures, not shavings for bedding. (Luckily we haven’t been using cedar shavings in the stalls, because the guy at the local co-op told us to use pine shavings, not cedar shavings. But thinking about it, maybe it was dumb to follow his advice and why would they sell cedar shavings if they’re unsafe? Anyway, back to trees.)

I checked out some university sites with lists of plants toxic to horses. I didn’t find red cedar on any of those lists. But oddly, the ASPCA lists a white cedar as toxic to horses, whereas the Ontario Ministry of Agriculture lists an eastern white cedar as a “safe tree” for horse pastures.

One of the best toxic plant databases I found was created for a masters’ thesis at University of Idaho. His thesis also makes for some interesting reading, if you’re into that sort of thing; some of his information made me rethink what I plant into our landscaping.

http://www.cnr.uidah...rses/index.html

The EPA has some registered uses of cedar oil in insect repellents for horses that are applied directly to the animal including no-rinse application. I didn’t track them all down, but one is called CedarCide.

I learned that in 2011 a Canadian dermatologist launched a product aimed at treating rosacea in humans (Riversol for Rosacea.) The product line contains thujaplicin derived from western red cedar and is touted as being “effective on even the most sensitive skin.” If you can smear it on humans, does that mean it's safe for horses?

o.k., I give up; I don’t know if those darn trees are toxic or not.


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## Carolyn R (Jan 9, 2013)

Hmmm, didn't know if it is from the cedar family, but I have vedco thuja zinc oxide ointment for equine wound care in the summer. Thick, hot pink, promotes healing while creating a barrier and repelling flies.


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## drmatthewtaylor (Jan 9, 2013)

Cedar shavings can be toxic to rats, mice, and other pocket pets.

Although I was unable to find specific references in horses, I found no toxicity effects in horses. Cedar can have irritant effects on the skin.

Dr. Taylor


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## hoofhearted (Jan 9, 2013)

Mine eat them..no problems here. Not gospel, my experience. They grow along fence lines, and are used as natural posts by just about everyone. In fact, you can often find old fence lines by the line of cedars..the seeds are spread by birds on the wire.


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## susanne (Jan 9, 2013)

My unscientific comment:, If cedar trees were toxic, we would have few horses, as so many pastures have cedars. Instead, we have many.

Thank you for posting the University of Idaho database. I get so irritated the extremely limited Cornell toxic plant list normally referenced. As a gardener and collector of unusual plants, I find few of the plants in my garden listed with Cornell.

I also like the ASPCA list, as it lists both toxic plants AND safe plants -- a safer reference than assuming a plant is safe if it is not listed.


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## Hosscrazy (Jan 9, 2013)

> Thank you for posting the University of Idaho database.


Ditto - very good resource!

Liz N.


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## shalakominiatureshowhorses (Jan 9, 2013)

We have a tiny cedar tree in the front pasture and HUGE cedar trees in the paddock used as a summer shade pasture only. We have never had problem ( don't want to jinx myself here ) but our goats chew on them. The horses don't mess with ours. They sometimes take a bite ( or attempt to ) on oak tree bark, but I have never seen them do it on a cedar tree.


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## Field-of-Dreams (Jan 10, 2013)

We had a huge cedar in our back field before it got blasted by lightning. No one ever really bothered it, and if they did, it didn't affect them at all.


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## Becky (Jan 10, 2013)

I have many red cedars here and have seen no ill effects with my adult horses. I do have occasional, unexplained fetal development/foaling issues and I may do further research as to whether the cedars could be the culprit.

The horses do like to rub on them some during the summer and cedar does offer a bit of natural fly/insect repellent.


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## disneyhorse (Jan 10, 2013)

We use a product here called "CedaRest" it might be local? It supposedly doesn't break down in mud.


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## Rockysticksfeatherfarm (Jan 10, 2013)

This is interesting but I will say from personal experience that I used to keep hamsters in cedar shaving and those are pretty delicate little things BUT on the other hand it was a no no for ferrets. Also a no no for chickens however.... Chickens are birds and like all birds have a very delicate respiratory system.... However.... I live in a cedar forest (juniper and the landlord said no to cutting trees) my chickens thrive and we haven't had a problem, we use mulch around the house as it is a big bug deterrent. Cedar is great for all kinds of things. My chickens use cedar perches and are fine (I have 4 year old happy healthy hens and counting) I think the caution was mostly for enclosed areas with no ventilation and baby chicks would be susceptible. But outside in the open air it's fine. Sap on the other hand is messy and makes me itch so I could see that being an issue with a horse getting it on their hair and skin. .... That's just what I know from personal experience


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## jsites (Jan 10, 2013)

We also have several large cedar trees in our pasture. We haven't have any trouble...yet. But a few years ago I remember reading that the "berries" can be toxic.


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