Is comfrey poisonous to geese?

Vlatro said:

I know I'm resurrecting an old thread here, but when I encountered it, I thought more information was due.

Comfrey is both good and bad, depending on how it's used. It's "healing" properties come from an alkaloid in the leaves that accelerates cellular proliferation. That means when living tissue comes in contact with the chemicals, the cells begin to divide. As such, when you put it on a cut, the cut heals over faster.

Animal bodies are not very good at disposing of these compounds, and they tend to accumulate in the liver, where cancer is likely. In that instance, it's like pouring gasoline on a fire. That is why people caution against taking it internally. That said, you would have to consume a lot of it over a long period of time (perhaps a few decades).

The onset of these effects would possibly be faster in smaller animals (though I don't know of a study that has explored that possibility). The truth is, most livestock won't live long enough to experience the side effects anyway. It can actually aid in weight gain in animals and help them reach maturity a bit faster. Again, I don't know of any good research that has been done on the animals fed high quantities of comfrey, but it stands to reason in my mind that if the animals are raised for meat, don't eat the livers where the chemical builds up. But again, you would have to eat a lot of goose livers from geese who ate a lot of comfrey, it's probably safe.

I have used it to help my birds gain weight and feather out faster, and also use it on my meat rabbits (specifically pregnant does). The impact is not that noticeable. There are a lot of hyped claims about this, but I personally can't tell the difference in performance between the animals fed comfrey and those that are not.

What I can say is this:

They love eating comfrey, and it grows in such abundance it makes for a reliable feed source which doesn't take up a lot of room. As soon as you harvest a leaf, another sprouts in a couple of days. The nutritional values are decent, though low on protein compared to other feeds. I have tried 3 varieties. Wild comfrey (a weed in my opinion), and two seedless cultivars, Bocking 4 (supposedly preferred by animals as feed) and Bocking 14, (actually preferred by my animals at least, used for soil improvement).

It's insanely easy to grow. Get a few root cuttings and stick it in any soil, nearly any climate. It will grow. The seedless varieties are propagated from cuttings. Every year, run a shovel through the middle of your plants, take half the plant away and plant it (or dice it into 20-30 pieces and plant them). Dress the plants with compost and soon you can have acres from a single cutting.

Some permaculturists advocate putting it under fruit trees as a living mulch that improves the soil. That practice has worked out well for me, though mostly because it keeps grass out from under the tree, and the long comfrey taproot doesn't compete with the tree's shallow feeder roots.

I recently purchased more for a new property from a company call Horizon herbs. They carry the seedless cultivars. It's a bit pricey to be honest (I think I paid $30 for 20 root cuttings), but the quality of the plants they sent was awesome. It's still snowing where I am and I have 10-12 leaves on each plant already, and they're huge, 6-8" in diameter. It's an excellent strain of comfrey.

I would not feed an animal exclusively on it, but I would be confident in making it about 5% of their feed. It is edible by humans (not poisonous). In fact, it tastes pretty good. It's just a matter of moderation. You would not want to have a comfrey salad or comfrey tea every day. Once in a while is fine. These health studies are important, but take it with a grain of salt. Technically speaking, a tablespoon of peanut butter has more carcinogens than a pack of cigarettes. That's not to say smoking is good, but if live you life by the results of those studies, you would be better off skipping the PB&J and sending junior to school with a banana and a pack of lucky strikes in his lunch box.
See: https://en.wikipedia.org/wiki/Aflatoxin (toxic fungus on peanuts)

So, are there risks to using comfrey in excess? Absolutely. But in moderation, it's benefits far outweigh the risks. Just like vitamin capsules, one can do some good, but eating a whole bottle will probably harm you.

Don't worry about the birds, they will thrive with some comfrey in their diets.

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Cottage Rose said:

I had a stand of Comfrey for many years and fed it to my chickens, goats etc. None died from it.
My geese ate it like it was candy.
So much so they killed it off.
None have dropped dead yet.
Comfrey makes a great topical poultice for injuries or rashes.

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