Tansy Ragwort in Horse Hay

Asked July 23, 2017, 11:59 AM EDT

I live in Sherwood, Oregon, and own a mustang mare whom I board at a private barn locally; the barn owner provides the local grass hay. My question is how much concern should I have over finding small amounts of tansy in her hay. I generally find small stems and flowers that I try to pull out, but I don’t catch everything before it’s been fed to her. If you look at the bale, you don’t notice it, but I do find it after she has spit it out. I have tried to talk to the barn owner about the problem, but they are extraordinarily sensitive about it and believe the hay is fine. I cannot afford to keep her at any other barns in the area since their cost is 2-3 times higher than what I currently pay. Do you have any thoughts? How much tansy can a horse generally consume before it becomes a problem? Any guidance, information, advice, or reassurance you can provide is greatly appreciated! Thank you so much for your time and expertise! Warmly, Christy Reckard Sherwood, Oregon

Washington County Oregon horses

1 Response

Hello Christy,
In regard to tansy. The entire above ground plant is toxic, even when dried and in hay. I have attached links to two reputable websites that talk about the amounts that are thought to cause problems. But remember every horse is different and what might not affect one horse could kill another.
Tansy is ranked as "highly" poisonous to both horses and cattle. The other very bad part about tansy is that symptoms (weight loss, lethargy, poor hair coat, off feed and jaundice - just to name a few) often don't show up for months post consumption. Rapid onset of symptoms is not commonly seen. The toxin is a pyrrolizidine alkaloid, which attacks the liver. If symptoms begin and it is known the horse was exposed to tansy, the outcome is not good. Recovery is rare.
In the links I sent you...you will see 50-100 pounds consumed over time to be the common number given; however, in the majority of the journal articles and poisonous plant books I have say "horses should never be allowed to consume any feed containing ragwort".
Would the barn be open for you to purchase your own hay?
https://oregonvma.org/care-health/equine/10-plants-toxic-horses (tansy is about half way down)
Let me know if I can help in any other way. You an contact me via email, which is listed below.
Tansy is nothing to mess with, fresh or in hay. I hope things work out for your horse's safety and your piece of mind.