First off, I'm thankful for a forum on which I can post a question about choosing POOP and get intelligent responses. It makes me happy.
So here's today's conundrum:
I have easy, ready, free access to too many poop options.
This is the set up: A bale-cob structure in central Oklahoma (where the wind really does come sweeping down the plain along with allergens from the four corners of the earth.) We want to finish the structure with dung-clay plaster for its a) accessibility and cost (or decided lack thereof) b) strength and water resistance c) the look and d) its non-toxicity/family-friendlier-than-lime-application in terms of safety. Yes, we have an generous overhang. Yes, we have a high stem wall. Yes, it will be protected from driving rain. Yes, there are layers upon layers of drainage in place. We're talking back ups to our back ups. There would need to be a flood of Biblical proportions for water to get to the plaster in any significant amount.
I have read that horse manure has more micro fibers but cow manure has more enzymes. Hmmm. And, okay, fine, the cows around here are purty conventional and eat sprayed grass and who knows what else and frankly, their poop sceers me a leetle bit.
HOWEVER, I also have access to "purer" cow manure, but it's a farther (further???) drive, (there's a conventional ranch literally across the street) as well as horse manure and POSSIBLY bison manure (how COOL would that be? "My house is coated in a fine mixture of native red clay, local sand and regal bison excrement.")
Does anyone have suggestions for what qualities to look for in manure, or more specifically, the animals from which the poop comes, when choosing what to use in a plaster that you will have physical contact with for an extended amount of time?? And, uh, am I over thinking this? AND hows about using a mixture of horse AND cow manure. I know experimentation is in order, but I wanted input from others concerning healthy poop for plaster. That is all.
Great thread. I think with all the variables of feed for manure you are going to want to make a few test plasters, something you have already thought of. I have only ever used horse manure and it worked extremely well. Make sure you crush/sift so that you don't get many clumps. I've heard the same, that fresh cow manure will make a more elastic plaster, easier to work with, but I don't know how true that is. I know people really like using fresh manure, but I have found that dry gets you a lot less bugs escaping from your plaster and ruining your finish. You will probably get less sprouting from cow manure I think.
I wouldn't go out of your way to get good quality cow manure, stick to a nearby resource if you are planning on making a lot of plaster and it will end up saving you a lot of time. Good luck!
Here is a my recipe:
1) Sift 3 (5 gallon) buckets of soil -- We used an 1/8" screen
2) Mix in water until a smooth (slightly liquid) mix is achieved
3) Sift and mix in 1 1/2 (5 gallon) buckets of sifted horse manure
4) Cook wheat paste
a) Boil 8 cups of water
b) mix 4 cups cold water with 3 cups flour
c) add flour to boiling water and simmer for a few minutes until thickened
5) Add wheat paste to mix and blend thoroughly
Zee - Horse manure is the traditional choice because of the larger size of the fibers - bigger fibers make for a stronger plaster. Horses are not ruminants which means the fibers don't get broken down into as small of pieces as the same food would in the multiple stomachs of a ruminant like cattle, goats or alpacas. Danial is correct, what the animal is eating also makes a difference. Grass can make a better fiber than alfalfa, unless the horse is eating some really coarse, stemmy alfalfa. But any horse person worth their salt will not be feeding alfalfa to horses. Cattle eating stemmy alfalfa will make a coarser fiber than cattle eating fresh grass. There's something to be said for a mix of the two as well, kind alike mixing various grades of aggregate to achieve a strong cement or non-fibrous plaster - earthen or otherwise. Having said that, there are times when a finer, smoother fiber is needed to make a smoother plaster, like inside on a highly visible wall. Then cow manure can work. For that reason I don't recommend using a ruminate manure in an exterior plaster. To make your plaster adhere better while making it much stronger and more resilient, add some femented or boiled nopal juice to the mix.
Avoid animals being fed GMO alfalfa or grass. It'll be contaminated with the bane of our existence, glyphosate (http://articles.mercola.com/sites/articles/archive/2015/12/15/glyphosate-modern-diseases-pathway.aspx#!) While working on a project for Fundacion APoy del Infatil in Sonora Mexico building low income straw bale homes, we had no manure or aggregate. Just lots of nice clay and lenty of wheat straw. I learned that if you put enough straw into clay and let it set overnight to soften up and allow the lignins to leach from the straw into the mud, you can make it do some really interesting things. If you can find lignins, use them. You might want to check out the "Natural Building" page and the "Cob Farm House" page here - http://erdakroft.com/Erdakroftfarm/Blogs/Blogs.html
"A nation that destroys its soils destroys itself." FDR
"We can't solve problems by using the same kind of thinking we used when we created them.” Einstein
Just about any of the Ruminant poos will work well then you have the Horse, Mule, Donkey poops that will have more undigested fibers.
Probably the best bet would be a combination of these instead of just a mono poop mix.
Mostly it would depend on what you can get and how much of it you can get.
Choice of Poop: Like others have said, horse (or donkey or other one-stomached hay-and-stick-eaters) will have longer fibers.
Cow and other ruminants, shorter fibers. Cow dung is very commonly used in Africa, however my experience has always been that it breaks down into sawdust-like micro fiber, not much holding strength for the crack-resistant base coat that I'm usually looking for on an exterior plaster.
I have not tried buffalo. I would imagine they're like a souped-up cow (because you can cross-breed them, and I have never heard of cross-breeding averaging out the number of stomachs between differently-endowed species....)
However, if they are eating a coarser diet, with bunch grasses and woody material, you might get more interesting fiber results.
Fresh dung, screened and/or soaked for a day or two, does seem to work best. I don't love picking out baby bugs (aka maggots) from older dung.
I have not tried dung from camelids including alpaca. They do chew cud so presumably, multiple stomachs and smaller fibers.
However, they have the interesting habit of always pooping in one or two piles in a pasture, making it easier to harvest than most other pastured herdbeests.
My biggest suggestion would be to do some test samples, try the different dungs and different proportions of fiber:clay. You can do entirely without sand if you want, but keep in mind you need a LOT more aggregate (sand or fiber) compared with the actual clay content. If your clay is too sticky, or you use too much, it will crack. Thus letting weather and bugs in, while probably not letting trapped water out fast enough to compensate.
I'd use quart tubs for proportions, mix about a bucket each of several options, and give it a test. Both on your wall, and on a smaller sample you can mess around with (bake in the oven, etc).
Try: (fiber/aggregate to clay)
It can be hard to get your clay to a really consistent, creamy texture so that your finish batches match your test batches. Start processing the clay early, let it soak a long time, and pay attention to how it feels as well as the proportions in each test batch. You may have to 'doctor' the subsequent batches (add a little more clay, fiber, or water) to get back to the consistency of the original.
There is nothing wrong with mixing fibers, but I would be hesitant to make my recipe more complicated than necessary.
It would be OK to mix in a second type of fiber if you run short on your main one, or switch types from coarser to finer for the finish coat.
Hair? If you have access to all these types of dung, you might have access to another fiber that some of us can't easily get.
Animal hair (typically horse or goat, hair rather than wool) was the traditional fiber of choice for hard-wearing plasters, and can be stronger for its weight than cellulose (dung, grass, or paper fibers). It may not be easy (pr pleasant) to get it from the hide-tanner processors in any condition you'd want to touch, but some people have good results looking up animal groomers, sweepings from pre-show grooming at local fairs, or other cottage-scale sources.
Health & Hygeine I do tend to wear gloves when getting my hands into plasters, even if they're the mesh-backed garden gloves. It's easy to sand off your fingerprints, or jab yourself on rusty tools or bits of wire that stick out of a bale, and then you have an open wound near potential disease vectors. However, if you are good with your plastering tools, you may be able to do the whole process without actually touching the plaster (common practice with lime-based plasters, whose alkaline ingredients are not good for skin).
I recently had a chance to ask about disease vectors while plastering with a naturopath who also studied veterinary medicine. My impression has always been that horses share slightly fewer disease with people than other farm animals. She didn't disagree.
In her project, she did go for a horse dung, supplied by friends who regularly worm their horses (using some of the more responsible/less toxic worming medicine), to avoid equine tapeworm.
She confirmed that from a disease-control standpoint, the diseases you can catch from horses may not be as numerous or severe as from some other animals.
With sheep or cattle, there are some more lasting nasties that could be transmissible.
From the CDC website's page on farm animals: https://www.cdc.gov/healthypets/pets/farm-animals.html Most livestock dung could contain e. coli, salmonella, and other bacteria or viruses such as cryptosporidium (most common in younger calves with diarrhoea).
Sheep, goats, and cattle are slightly more likely to carry anthrax, brucellosis, and a few other diseases.
Pigs would be significantly worse - they share more, and more serious, diseases with humans. But as they don't generally eat enough hay or woody matter to produce useful fibers, we avoid pig dung (and other omnivores' dung) anyway.
Some of the worst diseases that can be carried by farm animals would not likely be transmitted through dung, instead they are transmitted by mosquitos, or by eating raw milk / young cheeses.
So the biggest thing, whether or not you wear gloves, is: WASH YOUR HANDS BEFORE YOU EAT.
WITH SOAP. and clean water.
I like to use a big outdoor bucket for roughly rinsing hands and tools (keeps sand and clay from invading the plumbing).
Then wash again with cleaner water at a hose-tap near the house.
Anyone handling ready-to-eat food for other folks would be wise to wash again in the kitchen, just in case someone has contaminated the doorknobs or whatever.
I tend to keep tools in one area, and give all tools including the handles a good rinse at the end of the day.
And in case it's not obvious, I don't like to mix food processing gear with plastering/dirt-sifting gear.
If I need a fine sifter for finish plasters I will make a new one from window screen, not use a kitchen sieve or dehydrator tray.