Is cow manure dangerous to humans?

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Is cow manure dangerous to humans?

Also: Can you get sick from cow manure?

Is smelling manure bad for you?

What can be done with cow dung?

What chemicals are in cow manure?

Why is cow manure bad for the environment?

Is horse or cow manure better for the garden?

Is mushroom compost better than cow manure?

It would be wise to assume that cow manure is dangerous to humans. All manure is a source of pathogens which are harmful to humans. The danger from cow manure can only be a problem if you ingest it in any way. By taking simple precautions humans can avoid all the potential hazards that may come from cow manure.

We keep hearing that the best thing any gardener can do is to bring in a load of cow manure, rot it down into compost, get it on the garden and work it into the soil. But this means handling it and we shouldn’t forget that we’re handling faeces. If you don’t know it, you need to know that all faeces from anywhere carries pathogens.

This is the category that’s been given to all things bad and nasty that resides in fresh manure. It includes viruses, bacteria and a list of subgroups that end up being delivered from the digestive tract. These are things which you’ve got to keep out of your life.

Is cow manure dangerous to humans? Yes, potentially, wear gloves.

So, if you’re still wondering about the question, is cow manure dangerous to humans?

Yes it is, potentially, very dangerous and you need to take all the disease risks very seriously. Every form of food poisoning is available to you from the rich, ready and waiting source that’s in cow dung or any other sort of dung.

When you hear the names: E.coli, Listeria, Salmonella, Cryptosporidium’ and others, they’re probably mentioned in association with food poisoning. The source of this can only be from faeces and not just cow dung. All farm animals and poultry present a risk. We should also include all wild animals and birds together with pets when we think about disease hazards.

The good news is that you can make it safe for yourself and this is not difficult to do. By just observing basic hygiene rules you can eliminate all risks of catching anything nasty from any of it. Everyone knows that you need to wash hands and avoid eating or ingesting any part of it.  

Can you get sick from cow manure?

There will always be a risk that you can get sick from cow manure. There is a whole range of pathogens available in cow manure. Any or all of them are waiting for an opportunity to make you sick. The most famous one is E-coli but there’s Salmonella, Listeria and Clostridium, all found in cow manure.

The biggest risks are among those who have health problems. The need to protect others is the reason why we must avoid any onward contamination.

A strong, healthy person has a much better chance of fending off any challenges that may come from the dark side of cow manure. In an earlier life, I spent many years working among dairy cows. I was in contact with cow manure more than anyone should be, but I never at any time succumbed to any illness as a result. 

This, despite the fact that I had fresh cow slurry flicked all over me on a regular basis, sometimes finding its way into my eyes, ears and even in my mouth, spitting profusely immediately after. I’m not complaining here. This is just one of the ‘joys’ of livestock farming.

Is smelling manure bad for you?

Smelling manure is bad for you if you inhale the vapours that exude from a large quantity of manure in a confined space. The smell from manure should be taken as a warning to move to clean air. When you can smell manure, it indicates the presents of airborne chemicals e.g. sulphides which may be bad for you.

Catching a whiff of manure won’t harm you. You will notice it when it’s in the air. This is especially so if you are not at all used to smelling it. With most bad smells that are out there, it’s possible to become so accustomed to it that you don’t notice it after a while. 

From personal experience, this is true for most manures but I draw the line at pig manure. I can’t understand how anyone could ever become accustomed to the smell of pigs. 

The warning

There is, however, a serious risk from the gases that can be generated from manures of any kind. This is something that everyone should be fully aware of. While the odd whiff in the open air will do no harm, if you inhale methane or hydrogen sulphide gases in a confined space, it will kill you. 

The hazard that we all need to be aware of can occur where there is a build up of gases that have come up from a large quantity of slurry manure. This is often found in underground storage chambers. Never be tempted to go down into any such a chamber where there is slurry manure even if it’s to rescue someone. 

Methane and hydrogen sulphide are just two of the gases that manure slurry will produce. These gases are invisible and odourless. You can breathe it in, not realise that you’ve done so and then you fall unconscious. Then you will continue to inhale more toxic gas. Please know about this, be shocked by it, warn others and keep everyone alive.

The small quantities that we’ll be handling in the garden, in the open air won’t generate any noticeable toxic gasses. The smell won’t hurt you. So don’t panic.

What can be done with cow dung?

Around the world, there’s a couple of things that can be done with cow dung. In the most part, cow dung is a useful by-product which is an almost essential ingredient for feeding the soil. There are regions where cow dung is thoroughly dried and used as a solid fuel.

The best use of fresh cow dung, in the garden, is to make a heap of it and encourage it to rot down into compost. This will take some time and a bit of effort but it will be worth doing. 

Allowing fresh cow manure to rot in a heap will preserve any nitrates that you may have in the soil. If you allow fresh manure to rot on the soil surface, the rotting process will pull nitrates from the soil and release it as nitrogen. We want all the nitrates in the soil to stay there for the plants to use. 

Making compost from cow manure will allow nitrogen to escape from the heap. This won’t mean losing any of the other nutrients e.g. potash and phosphates. It will help if you cover the heap during the rot-down period. This will reduce the leaching out of nutrients when you have heavy rain.

You can speed up the composting process by digging the heap over and adding hydrated white lime. Take a look at Making compost with cow manureto get some more ideas.

When you have a well rotted heap of compost, generated from cow manure, you will have a stock of some of the best compost anywhere. It will be good for growing potatoes, good for fruit trees, it will be the best you can get for growing anything. 

There is guidance to avoid problems

There are chemicals in cow manure but they are all naturally occurring. While there are potentially dangerous pathogens in cow manure, the chemicals found in cow manure are not a hazard. Chemical compounds that you can expect to find in cow manure will be nitrates, phosphates, potassium and some ammonia.

You may want to spread fresh cow manure on the ground. The United States Agricultural Department has a National Organic Program which insists that you must allow at least 120 days between application and harvesting of food crops. This is particularly important where any food crops come into contact with the soil.

The 120 day ruling means that the timing of application is, in some cases, compromised. In some districts it may be better to apply any fresh manure in the Autumn and allow the 120 day period to expire through the winter months. Then cultivate the ground in the Spring. 

The only down-side to doing this is that the weeds will be more of a challenge in the new growing season. However, the manure should be completely broken down by the Spring-time, making it easier to work the ground.

What chemicals are in cow manure?

Here we have to differentiate between naturally occurring inclusions that emerge in fresh cow manure as a result of the cows’ standard diet and chemicals that are an input for management reasons.

On analysis, there will be clear indications of a range of elements that are conducive to those which can be found in the basic diet of any herbivore. These will include nitrates phosphates and potassium. There will also be a range of metals. All of these will be very low concentrations.

Further to this, there may be the presence of synthetic compounds that have been administered for parasite-control reasons and have survived, without breakdown, through the digestion.

One such compound that has been in wide use is ivermectin. This is used as a parasite controller. Manure generated from cows that have received ivermectin will almost certainly show traces of it.

Should we worry about ivermectin? No. It’s been in use for many years and there have been no reported problems. It’s generally recognised as being very safe to use. 

However, there does appear to be a problem in fresh cow manure as regards the early stages of decomposition. This is the stage where small insects, for example scarabs and others, consume what they can. The presence of the ivermectin compound in the fresh manure, deters them from doing anything. 

This isn’t critical to the degradation of cow manure. If allowed to progress and with all other factors being equal, fresh cow manure with traces of ivermectin will decompose and become compost. It will happen without the normal early-stage intervention from insects.

 Why is cow manure bad for the environment?

Cow manure is bad for the environment because of what it contains. There are large concentrations of nitrates, phosphates and pathogens which need to be kept out of water ways. A large quantity of cow manure will generate a liquid that contains these compounds that can be bad for the environment.

Cow manure, in small quantities, has no effect on the environment. There are, however, justified concerns about large concentrations of cow manure that are sited in one place. A selection of vapours are going to be emitted. The immediate effect of this is likely to be odour. 

On a site where cow manure is being constantly generated, the vapours associated with it can be an irritating constant.  There’s very little among that which is released into the atmosphere, that will have any long lasting impact. Despite the fact that a large concentration of vapours can be released into the atmosphere, it will all become broken down and reabsorbed into the ecosystem without any lasting consequences.

Every gaseous compound that’s released can be seen as naturally occurring. They will largely include the elements, carbon, hydrogen and oxygen. All will convert by natural processes into mainly CO2 and water.

The biggest potential problem that can have a longer term effect is the liquid that may drain away from large quantities of cow manure. This is likely to be very concentrated and must be channelled away from any waterways that lead to streams, rivers and the sea. 

The risk is extended when cow manure is spread on farmland as an organic fertilizer for crop production. However, the risk of polluting by spreading cow manure on the land is significantly reduced if it’s spread at low concentrations. With careful management, it’s very possible to spread enough cow manure on farmland without allowing any potentially harmful liquids to drain through the soil and flow to the waterways.


Fresh cow manure on your garden is unlikely to pollute


A large concentration of cow manure has the potential to release large amounts of phosphorus and soluble nitrates among other compounds. All of this would be useful in smaller, less concentrated quantities but large doses in a confined area will pollute ground-water including drinking water. 

If a large amount of nitrate and phosphorus-rich liquid drains from land to sea, there may be a sufficient concentration to create, what’s known as an algal bloom. This is when the concentration is so high that algae, to which phosphates and nitrates are a food, can thrive so well that it multiplies very quickly. In some cases the area that an algal bloom expands over, can be so big that it can be seen from space.

But none of this should be a worry to us in the garden. We aren’t going to have access to such large volumes of cow manure such that we are going to do anything bad to the environment. However, it must be pointed out that if you take delivery of a sizeable load of cow manure, be careful about where you tip it. 

Have a look around and find a place to tip it where there is less risk of any liquid running off and into drains. If any juices from the stored heap of cow manure go into the drains, you will be polluting that immediate waterway. You could argue that it will dilute as it goes further along but that’s no excuse.

Apart from anything else, these are valuable liquids that are getting away. They contain phosphates, potash and some nitrates which you can make better use of in the garden.

Is horse or cow manure better for the garden?

There’s very little difference between horse or cow manure. It’s difficult to say which is better for the garden. Horse or cow manure will make compost for the garden. Horse manure tends to heat up when making compost due to the higher dry-matter content. Cow manure often needs more dry matter added to it for compost.

Horse manure tends to have more straw added. This is because horses are mainly kept as pets, so horse owners tend to make them more comfortable by giving them more straw to lie on.

Where as with cows, they tend to have to make do with less straw, mainly for commercial reasons. This isn’t to say that cows aren’t being cared for. They get enough straw but they rarely receive the same amount as horses. 

The extra straw in horse manure will often result in the manure heap generating more steam as it goes through the early stages of rotting. Cow manure will also generate heat and steam but if ever there was a contest to establish which would produce the most, the horse manure heap would win.

None of this will make any difference to the final outcome. If ever I’m offered the chance of either, I would take both.

Is mushroom compost better than cow manure?

There’s nothing about mushroom compost that makes it better than cow manure. There will be a valuable range of nutrients that can be found in both. Mushroom compost will be easier to handle than cow manure because it’s been processed into the friable material that is compost. Cow manure is at the pre-composting stage.

Given the choice of mushroom compost or cow manure, I would go for the latter. But it depends on what you want to do. Mushroom compost will be ready to go straight into the garden. It will have some nutrients in it but you have to realise that it will be mostly spent as a fertilizer. 

Mushroom compost also has a bit of an advantage because compost that’s used for growing mushrooms is heat treated before being released for others to use as a garden compost. This will mean that no weeds or mushrooms will sprout from it.

Cow manure will definitely have the edge over mushroom compost. You will have to wait a while for it but if you dig it over in the making and add some hydrated white lime from the outset, then you will have the most nutrient-rich compost that’s going.

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Cow manure dangerous to humans?

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