Using Horse Manure In The Garden - Horse Wormer Concerns???

I was listening to a Permies Podcast yesterday that discussed earthworm deaths from horse wormer that had passed thru the horse and out into the manure. I read a bit out on the web what other people think and apparently they seem to think it's in the 1st 2 weeks after being wormed that is the biggest concern. So what do we think? Can I contact the stables I get my manure from and clean the stalls of the horses that haven't been wormed recently and then compost it myself back on my own land? Another person said that if the pile has been composted it should "burn" out any of the chemicals or they could also leach out as the pile gets rained on etc.

Thoughts???

A caveat...I'm pretty casual about using stuff that others won't.
As far as I know dewormers in manure are usually dangerous for the first week or three.
I don't worry about it apart from leaving the manure for a few weeks before adding to compost, garden etc.
I don't know if you have worse dewormers, but if you're worried, it's worth printing out a list of common brands/toxicities and asking the farm what product they use. If they use one that's not common, I'd be wary...

Ivermectin (22,23-dihydroavermectin B1a + 22,23-dihydroavermectin B1b) is a commonly used horse wormer medication. Believe it or not, it is listed by the National Organic Standards Board as a synthetic substance approved for use in certified organic livestock and crops. I have used compost I made myself which included horse manure from 5 horses I personally met, treated with this med by the owners, who I hold in high regard and I consider them to be absolutely wonderful in caring for the horses. The result was a rapid and significant reduction of the worm population in the beds to which the compost was applied.

Two years ago I moved to my current property. About a mile away is an animal rescue farm. I was offered all the manure I could haul off. It was well aged. I took 2 loads, figure 4 cubic yards. I offloaded it all into one pile, then applied it to some new garden beds. While the crops were a disaster as a result of drought and neglect, those beds have produced poorly compared to beds not treated with that batch of manure. The spot where I offloaded the stuff grows nothing to this day, not even weeds. An area less than 20 feet from this spot was dug up for other reasons, dried up, left as a pile of bare sand and is now as green as the rest of the lawn. 50 feet from the dead spot the local utility sprayed picloram around power poles as well as along my fence. One area of spray extended into my front yard, covering an area 6-8 feet deep, 16 feet wide. In this sprayed area everything green died. Weeds began growing back within 6 months. I dumped that manure in early summer 2 years ago-still no growth, not even weeds. The animals which produced the manure were treated with whatever the rescue farm could get their hands on using their limited budget.

I will not use manure from a treated animal or compost which included it. Ever.

YIKES!!! Ok so maybe just forget about manure all together, as it could be a huge pain in the @$$

I have a bull in the back field. He produces more doo than I can gather. I also have a bunch of chickens. I don't treat these critters, use their product freely.
I'll use the poo from untreated critters, but it's hard to find them.

Using manure in compost is important. Animal manure contains proteins and enzymes which greatly impact the resulting compost and the crops grown with it. I don't fully understand how the process works in a dynamic compost heap with manure included-it's complex. I do know that crops grown (caveat: in my sandy soil) using only vegetative compost are stunted.

Woah Ken, that's scary! It makes me wonder that maybe the animals had eaten hay treated with one of those full-on systemics like clopyralid?
I've never heard of that kind of reaction from a dewormer.

Take into account the fact that what is called 'soil' down here is over 90% sand. There is not much for soil life which could help in breaking down 22,23-dihydroavermectin B1a + 22,23-dihydroavermectin B1b or what have you. Organic matter, including manure, added to the soil is rapidly consumed in a microbial feeding frenzy. This stuff seems to persist even after the frenzy. Also bear in mind the drought that has been ongoing since August 2010-a couple months after I picked up the tainted manure. It may be that normal rainfall would wash the stuff out. I don't have a control plot and experimental plot to compare.

I picked up some aged manure from a horse stable up the road and have yet to see the results of incorporating it into the garden at my new place. I am (now cautiously, after hearing Ken's account) optimistic because the pile from which it came had a bunch of very healthy looking weeds growing around it (malva neglecta, milk thistle, etc). I'll quiz the operator about wormer next time I pick up a load. I wonder if there is any seasonality to when horse owners use wormer.

I've used horse manure that I'm pretty sure had wormer chemical in it, and the plant growth was good enough to net about $11 000 in veggie sales on less than an acre in the first year of no-till cultivation. I say pretty sure because there are a lot of horses (about 20) that contribute to the pile I draw from, and most are individually owned so I'm assuming that at least some of them (probably most) use chemical de-worming agents. On the plus side, I'm told that other than this, there are no synthetic treatments added, including no anti-biotics. There's probably chem traces in some of the grain feed though.

I'm guessing that my yields and plant health would have been noticeably better without the chemical in the manure but until I get the veganic methods down, I have little choice.

Travis Philp wrote:I've used horse manure that I'm pretty sure had wormer chemical in it, and the plant growth was good enough to net about $11 000 in veggie sales on less than an acre in the first year of no-till cultivation. I say pretty sure because there are a lot of horses (about 20) that contribute to the pile I draw from, and most are individually owned so I'm assuming that at least some of them (probably most) use chemical de-worming agents. On the plus side, I'm told that other than this, there are no synthetic treatments added, including no anti-biotics. There's probably chem traces in some of the grain feed though.

I'm guessing that my yields and plant health would have been noticeably better without the chemical in the manure but until I get the veganic methods down, I have little choice.

I


I have hauled about three pickup loads of horse manure over the winter. Some of it is still in the compost pile which is teaming with worms.
The rest was composted for a time and spread on the beds. Worm activity is very encouraging so far. So far so good.

It's standard practice in the horse world to rotate de-wormers (use a different one each time) in order to cover a wider variety of parasites and help prevent resistance. When I had horses, vet's recommended de-worming every 8 weeks. Ivermectin and Strongid are popular ones--but there are many to choose from. You are probably looking at a variety cocktail throughout the year. We never experienced any dead spots from manure from any time of year with any de-wormer. It's always been lovely, black gold!

Oh yeah, I forgot to mention that the manure pile, and the garden spaces that I placed said manure on, are teeming with red wiggler worms

Travis Philp wrote:Oh yeah, I forgot to mention that the manure pile, and the garden spaces that I placed said manure on, are teeming with red wiggler worms

Who can say what was in the bad manure mentioned in some posts. Generally speaking Manure is a proven
benefit to growing plants since the dawn of time. First the de-wormer has to go through a horse and it is designed to kill the
worms in the horse so it has to go through those worms. Then I am going to mix it with 3 or 4 varieties of leaves
and kitchen scraps and heat it up. I have been warned and I heard it.

So what it boils down to this, I am going to get paranoid on something else. For example
my neighbor said I could go up to the Dekalb market and get tomatoes for .39 cents a pound he opined that
all the soil in my area had "blight spores" in it. He has always "farmed" in buckets with expensive soil from a package
that was supposed to have perfect ph, etc. I didn't mention to him that it costs me $40 to make a round trip to
Atlanta and he is no different. I also give nature some credit to compensate for my mistakes. I keep putting
organic matter on my beds and at some point the worms will take it and run with it. Then that glad day I will do
like my kinfolks in the Mississippi Delta do just stick it in the ground and it grows and does so quite naturally.

We had a horse show in town, and I have picked up the grass and manure they threw out of the stables, and composted with it. Works perfectly. As is is a lot, I'm still going from time to time to pick up some. I got a load 2 weeks ago, and the manure and gras have been laying on the pile at the stables now for 6 months. I fed a bunch to my worm farm (red wriggler wurms). They immediately came from down under to eat this lovely stuff and they thrive on it.

So it seems that it should just be properly aged and composted.

I've been making wind row compost piles of horse manure and stable bedding. The piles are usually 10 to 12 cubic yards and compost for at least two months. I turn it frequently enough that it is really well composted. I usually get temps of 140 to 150F for a few weeks, then 120 to 130F for another couple weeks.

I've never had any problems with weed seeds or worm die-off. One of the two sources I use medicates. Who knows what was used on the hay.

I've had lingering concerns about horse manure toxicity and so I performed a simple test to see if my seedlings were affected. I filled one 32 oz yogurt container with a large amount of compost and some peat (my control pot) and another with a similar amount of horse manure and peat. Planted 4 comparable seedlings in each. Waited a few days. And those in the manure pot did just as well if not better. (You can get more details of my test at www.nutrac.info post dd 3/15).

So I was feeling good until I heard the podcast. I then expanded my test and 3 days ago put a comparably sized (4") earthworm in each pot. Today I emptied the two pots hoping to find a healthy, happy earthworm in each pot. But only the compost pot had an earthworm. What happened to the guy/gal in the horse manure pot? Maybe it was naturally adventurous and absconded; or took a whiff of the manure, identified the dewormer and beat a hasty exit; or succumbed to the dewormer and dissolved. So I rank this test inconclusive and next time I collect horse manure I will reperform the test, and make sure to lid the container.

I was happy to find lots of earthworms, big and small, in my manure treated garden after heavy rains this weekend. So far so good.

Many horse owners like me deworm their horses every other month by rotating though Pyrantal Pamoate, Benzimidazole and Ivermetcin twice each year. They are meant to kill most of the worms within a day or so of treatment. The worm population begins to recover quickly so the next round of treatment is needed before the worm population gets out of hand. Penn State says that the average 1000# horse produces 50# of manure a day, so the wormer would probably be measurable for only a day or so.

Some horse owners use a daily wormer or daily feed through fly control. The feed through fly control is meant to pass through the horse's gut and interfere with the growth cycle of flies. Either of these could possibly interfere with soil biology.

But if the manure balls and bedding breakdown over time into compost, some types of soil organisms are surviving. I have spread the composted manure of my 3 horses on my gardens for the 5 years I have had them, each year I get better results. In fact I picked up almost 2 full-sized pick up loads from a neighbor to expand my gardens and I expect great results.

Larry.

I have used horse manure for years I get mine from hobby horse owners in my area. I have always had plenty of very large earth worms. Manure from any animal is very high in nitrates, also I do know that worms are very sensitive to high nitrate soils. Perhaps the problems some of you are experiencing is due to the manure not being composted well enough? I like to let the stuff I use cook for at least a year.

I think there are a lot of bigger things to worry about. For god's sake don't stop using manure over it., it's vital that we start closing nutrient cycles if we're going to approach a sustainable agriculture. My cattle are treated with ivermectin and the horses with a few different wormers, I use lots of manure and have lots of earthworms.

A 1400 pound horse cranks out 7.5 tons of manure a year. There's a few ounces of wormer in there and even less of the active ingredient. And it's going to degrade in the compost with heat / biological activity / leaching. If wormers were that effective as a soil sterilant the herbicide companies would be all over them, and farmers wouldn't be lining up to buy manures as an ammendment.

Horse manure was my grandmother's fertilizer of choice - she called it gold for the garden. I used to use it until I started learning more about permaculture. After spending 40+ years handling pets and livestock I now have serious concerns about Ivermectin in particular. The last word I had on this (10 years ago) was that there were NO parasites resistant to it at that time.

Anyone who has dogs in the south is more than likely giving ivermectin to thier dogs for heartworm prevention, used on cattle as a pour on for flies, internally for horses, goats, sheep etc.

I have been searching for a poo source from a few 'sustainably' raised animals only to find that all have been given ivermectin.

I do wonder if there are parasites that have developed resistance to it.

If you are concerned about ivermectin there is quite a bit of conflicting information out there on the net about whether or not it is causing problems or changes in our environment. I have a hard time believing that a chemical that can kill ANY parasite will not cause a disruption or change in the cycle of life.

For that reason I am going to use only the poo generated by my own birds that are given only DE.

Over the past number of years some parasites have become resistant to to active agents of all 3 of the mainstream wormers. The goal no longer to kill 100% of the parasites in a horse but to keep their numbers low enough that they don't put too much pressure on the horse.

Larry.

We fertilize with goat pen sweepings. First we spread straw in the pens, then rake everything up after a few weeks and put it all down in the garden either mixed into the beds with vegi compost and DG, or as top dressing/mulch. We deworm by spreading DE on their food several times a week, and by letting them eat wild tobacco and other natural remedies. Our animals and our garden look great! Note: Before you use goat, make sure you're OK with the unique scent. Does smell light and fresh, but buck pen sweepings should be relegated to the back forty!

We stay away from horse biscuits as a rule. We have also had worm die offs from commercial meats, dairy products, and pies. Not entirely what they are feeding us in those.

Not sure if anyone has considered this:

Alot of times, horse manure is mixed will old wood shavings. Those shavings can take a heck of a long time to decompose, and actually suck nitrogen from the soil in the process - I'm not sure if it would cause a worm die-off, but it sure keeps the plants from growing. I learned this one the hard way, sheet mulched a whole front yard a few years back, and covered it with a foot of manure/shavings that had been sitting for over a year....had no idea why things just did not grow. woops.

A few things to consider would be that horse pastures still have things growing in them. Their poop doesn't kill off the pasture. Also dewormers are designed to kill specific intestinal worms; not all dewormers kill all intestinal worms, hence one of the reason you need to rotate through different types of wormers. Red wrigglers and earth worms are not intestinal parasites, and are also notorious for inhabiting manure piles. When I first got my red wrigglers I read that horse poop makes the biggest worms. I have been feeding them horse apples for multiple years without any problems.

Recently, here in WA state, there has been mounting concern that nearly all of the commercial hay is being sprayed.
Perhaps the pest/weed controls being sprayed on the hay fields is the major concern.
Or, the combination of 'tainted' hay mixed with the worming medicines.

Animal manures are essential for a healthy soil food web.
Some of the mycorrhizal fungi are carnivorous - inverting animal manure into forms the soil/plants can consume.
Are we tainting our soil food webs with bastardized manures?

Ken mentioned that the spot he had stored his manure pile hadn't regrown grass or weeds. I gather that he attributed that to toxic manure. But there are other explanations. I don't profess to know the exact reason(s) , but I've seen that same effect from other situations where light, air, and other environmental factors were kept from the soil.

Examples I've seen ....
1- An old garden shed was removed after sitting on the site for several years. It took two years before any grass or weeds started to repopulate the spot.
2- A friend had covered an area 20'x100' with heavy black plastic with the intent of killing the grass and then planting fruit trees. Due to other reasons he never got back to the task for 3 years. He removed the plastic, planted his trees, and now 3 years later the grass and weeds are just coming back, but sparsely.
3- I stockpiled 30 cubic yards of mulching material beside one of my garden sites. It sat there for many months, maybe well over a year, until I used it all. One year later the spot is still bare.

So instead of toxicity, perhaps there are other factors at play.

...SuBa
www.kaufarmer.blogspot.com

We just picked up "aged horse manure" from a farm today -- it did not occur to me to ask the owner if wormer had been used. I hope that since it has been aged for a year it is ok. We're using it for worm composting.

Regarding long-term possible bad effects of manure: SALT (NaCl plain or mineralized) added in quantity to animal food, or offered in a way that it falls into the manure or bedding, could be a problem? A cattle rancher, who grows and stores hay for their herd, salts between layers of baled hay when putting it into the barn, if the bales had gotten rained on. North-Central Idaho

All of the different experiences and thoughts in this thread are great but unless we have some real numbers or statistics to go along with them, we are kind of walking around in the dark. So does anyone know of a soil lab that will test for the persistence of different chemicals in the soil; specifically dewormers, antibiotics and other livestock treatments?

!!! CAUTION!!! DO NOT USE ANY MANURES THAT HAVE COME FROM PLANTS CONTAMINATED WITH ANY WEED HERBACIDES!!!

We have been using and distributing organic composted aged or fresh horse manure and worm castings for over 50 years. We have them tested for medications, insecticides, herbicides, salts and ammonia.

Our compost is certified Organic because of the ingredients in and the composting process.

Fresh manure is dangerous to worms and gardens if not treated properly!!!

Only 10% of Ivermectin and other medications pass into fecal matter and urine. They usually break down within 3 days of exposure to sunlight (UV light).

Medications are NOT a problem for worms or gardens if the manure has been spread and exposed to Ultraviolet Light for 3 days.

Fresh and aged manure has three primary problems for worms and gardens:

1. Ammonia: even manure aged for a year in a pile may have sufficient ammonia to kill worms and plants.

2. Salt: horses are usually fed sufficient salt that passes through in urine and fecal matter to sterilize soil and kill worms.

3. Potassium: A ratio of about 1/.5/.7 is often found in great stable manures. Unfortunately, the potassium is not used as quickly by plants and can build up in soils where it binds to the molecules. Watering does not wash it out like nitrogen.

Rain, watering or rinsing manures will solve these problems; the rinse are may be great for soils (anhydrous ammonia binds to soil [GREAT], OR salt may contaminate groundwater [BAD] and kill worms.

Fresh manure rinsed thoroughly twice is safe for gardens and worms.

This rinse water can be diluted and used as a liquid fertilizer on gardens but not in bright sunlight. Cover a bucket of biscuits with sufficient water and change twice in 48 hours.

Use one cup of this concentrated rinsate per gallon of water for outside plants and grasses. Dilute to 1/4 strength for inside plants.

Add one ounce of worm castings and molasses and aerate 24 hours to make an amazing fertilizer/worm tea drench that also repels pests.

HERBACIDES such as those designed for Rourndup Ready Alfalfa and grass hays contaminate gardens for at least 3 and over 10 years. They sterilize soils except for corn, onions garlic and grasses.

THIS IS CURRENTLY A VERY DANGEROUS PROBLEM FOR GARDENERS.

KNOW THE SOURCES THAT GOES INTO YOUR MANURES!

Use of more than 20% manure yearly can contaminate soil. Our organic worm beds and garden beds start with 66% compost and 34% clay soil, remixed with 66% compost the second year. 2” of compost is added spring and fall on top thereafter. These beds grow AMAZING plants and worms.

(385) 202-4446: Text if you have questions!

Greetings. My first post here! Woohoo!

I agree with the need for facts and figures. Found this website as a useful source of factual information.
https://www.redwormcomposting.com/worm-farming/how-harmful-are-vermicides-in-manure/

For those otherwise not able to look at the site, the two main quotes for me are;

"Fortunately for gardeners and animal owners, most research to date indicates that Ivermectin, the vermicide most frequently given to horses, cattle and sheep, breaks down quickly once it is excreted. Several studies have shown that Ivermectin degrades rapidly when manure is hot-composted or exposed to sunlight, and somewhat less rapidly when manure is simply piled up and left to decompose.
A study of Ivermectin-treated sheep found the half-life of the chemical in sheep manure to range from seven to ten days. Because of quick decomposition, Ivermectin preparations given to animals have not been found to build up in manure-amended soil."

and

"The most common wormer used is known by the brand name Ivermectin®
made by the Merial Company. Merial’s research shows that the active chemicals in Ivermectin® are deactivated when manure is exposed to sunlight. Equine studies show that 95 percent of the active chemicals in Ivermectin® are deactivated in the horse before being passed in the feces. Leading experts in vermicomposting believe that the concentration of Ivermectin® in the horse manure is not high enough to seriously injure Eisenia."

They also mention the salt, phosphorus and ammonia found in manure, for a variety of reasons.

My conclusion in all this? I will use horse manure, but only from a location where it is collected from outdoors - paddock not stable eg our local pony club - to give the sun its chance to deactivate any lasting wormer. And only after it rains, to give the salts and phosphorus a chance to wash away.

An alternative to placing manure onto a garden or in the compost is to make a liquid manure out of it - buckets, drums, old bathtubs, etc.

A brew may also include weeds.

Since the resulting liquid is left to steep for a few weeks, some/all of the nasty stuff should be dealt with by microbes and/or UV.

Also, before use it's reduced in concentration as 1:4, further reducing any possible harm, including the high urea content if it's fresh from stalls.

I tend to use my own chooks manure as a liquid fertiliser - leafy green vegetables jump out of the ground ... maybe due to the smell!😉

Very interesting thread!

My local organic farmer has just alerted me to the issue of vermicide in horse manure, so I came searching for more information. It’s too late for my garden now, after piling manure on it for the last 10 months but one thing I have noticed is that the composter does not seem to have the number of red worms that it used to before I started adding fresh manure to it.

The manure heats up the compost bin wonderfully - the food and garden waste additions break down rapidly, even in cool weather. So, from the point of view of compost production, it still seems worth putting manure in. However, this year the rhubarb and beans were much less productive than usual after mulching them with fresh manure.

Of course, without doing a controlled experiment it is hard to say that the manure is the (primary) culprit. But since the aforementioned farmer has offered me her organic cow/sheep/pig manure, I think it prudent to make the switch.

Ivermectin is used routinely on most cows, sheep, goats and pigs too, so switching from horse to another livestock manure won't necessarily eliminate it if that is your specific concern.

I have used plenty of manure from wormed animals in the past 50 years of gardening and will continue to do so. Horse manure in particular is a 'hot' manure and needs to age a long time. In some climates a year may not be long enough. Otherwise it will burn your plants and worms. This has been known by farmers and gardeners for centuries.

Helen Butt wrote:Very interesting thread!
But since the aforementioned farmer has offered me her organic cow/sheep/pig manure, I think it prudent to make the switch.

Organic manure can still have wormers in it. Organic regulations do not stop necessary medications.