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Animal Fertilizer

As long as individual animals live in their natural environment, their excrement is a valuable fertilizer for the soil. Due to the high demand for meat, dairy and eggs, however, more and more animals are being kept in ever smaller areas. The soil can no longer absorb the enormous amounts of animal excrement that is generated.

As a result, the excretions of animals enter the air through evaporation (ammonia) as well as seeping into the groundwater (nitrate). The fish in rivers and lakes die from this overfertilization. It causes an explosion in algae growth, which in turn uses up the entire oxygen supply in the water and suffocates all remaining life. This process is responsible for eliminating life in a large part of the Gulf of Mexico.
In the US, this contamination from the meat industry is 130 times higher than that caused by humans.

Hardly any vegetable is grown without the use of animal manure. At a minimum the feces of so-called “animals for slaughter”, liquid and solid droppings alike, are dumped on almost every field nowadays. A significant producer are the land-independent animal factories. So many animals are kept in these large barns that their waste poses a disposal problem. Furthermore, pigs, for example, are unlikely kept in open habitats, where (given sufficient land) their excrement would be easily distributed.

Although around half of the meat consumed in Switzerland comes from pigs and almost all pork is produced domestically, you hardly ever see pigs in nature. They are held in pens. And the waste from these pens has to be disposed of somewhere. The easiest way to do this is to spread it as fertilizer on agricultural land.
If you shop in a supermarket, you can be certain that the vegetables are also grown using animal matter. Unfortunately, organic farming does not offer an alternative here either. Even today, organic associations, besides animal feces, still allow horn shavings, hair and feather waste from slaughtered animals to be used as fertilizer for their fields. Most associations in the EU have now banned blood meal and bone meal because of the BSE problem. In Switzerland, these products of slaughter were long used in plant agriculture.
In the Bio-Suisse guidelines (Knospe) of January 1, 2001, it is stated in regard to permitted fertilization and soil improvement (Appendix 1, Section 2):

«Products and by-products of animal origin such as horn-, blood-, bone meal, hair and feather waste."

This was changed due to BSE and the new laws that followed1. Blood and bone meal are no longer allowed (directive of 1.1.2004).
The extent of which fertilizing with animal feces is considered a matter of course can by seen in the choice of words in the Bio-Suisse guidelines, where cattle are referred to as «Düngergrossvieheinheiten» or manure large livestock units.
Vegans and many vegetarians reject such animal fertilization practices. Unfortunately, there are only a few farmers who have recognized the advantages of purely plant-based fertilization. Such products are therefore barely available today.

What are the issues of fecal manure?

Several problems arise from current animal fertilization practices:


The amount of animal excrement produced by meat, dairy and egg production is greater than the soil can handle. A small amount of manure, which is naturally present when animals graze on fields, does not pose a problem concerning overfertilization. Nowadays, however, pigs and chickens particularly are kept in stables all the time as a rule and the resulting dung and urine must be disposed of somewhere else. This causes certain areas to receive too much manure resulting in materials penetrating the groundwater directly.
You can observe this, for example, at Lake Sempach, which resists complete suffocation from the feces of the surrounding hog fattening plants only due to artificial ventilation.
Flora is also negatively influenced by this overfertilization. Consequently, biodiversity is decreasing.


It is becoming more and more evident that the high levels of antibiotic use cause the bacteria that it combats to become increasingly resistant. Therefore, people are starting to utilize antibiotics more cautiously.
Although the use of antibiotics as mere performance boosters has been banned in animal husbandry, around half of antibiotics are still used by animal agriculture
3 (the other half in hospitals, etc.).
An animal treated with antibiotics must not be slaughtered immediately thereafter, as the meat would otherwise contain too much antibiotic residue. But what occurs with the administered antibiotics in the animal's body during these instances has not received enough attention: within hours, most of the medicine is excreted through feces and urine and thus enters the environment. The aforementioned Lake Sempach also contains higher concentrations of antibiotics for this reason.
The widespread prevalence of antibiotics in nature caused by animal agriculture poses a major and not yet adequately studied risk to the environment: Will this induce new resistant pathogens? What kind of influence does this have on vegetables, fruits or other foods?

Soil life

Natural soil is full of life: countless microorganisms, worms, beetles, ants and many more reside on or in it. The effects drugs used in animal farming have on the soil have so far hardly been researched. What is clear, however, is that antibiotics (whose purpose is to destroy life: anti-«bio»-tics) do not exactly promote life in the soil. Bacteria are the dominant group of microorganisms in the soil. It is estimated that there are 106 to 109 bacteria in each gram of soil.5 It is precisely these bacteria that are especially affected by antibiotics.

In addition, the large amount of feces favors those creatures that require or desire a lot of nitrogen and disadvantages other life forms. This can disturb the natural balance of life in the soil. Biodiversity it not only endangered above the ground, but also within the soil below it.
Farmers who have not loaded their soil with feces for many years have found that their plant-based soil evidently attracts fewer “pests”. This could, on the one hand, have something to do with the absence of the stench, but could also be due to a greater diversity of useful soil organisms.

Myths and constraints

To question animal fertilizer in agriculture is often considered heretical in and of itself. Manuring has always been considered integral to an optimal and natural nutrient cycle: The animals are fed the grass from the meadow that they once fertilized. Today, this idyllic representation is sustained on organic farms at best. Yet even there, some of the same issues described above arise.
For meat producers it is absolutely crucial to perpetuate this myth of the natural cycle. If it were not possible for animal owners to spread the feces from the animal factories onto the agricultural land, they would face a disaster scenario. So there exists a practical constraint that prohibits questioning this practice.
The stench of manure has become an indispensable part of today’s agriculture.


Although fertilization with animal feces and other animal products is not welcomed by vegetarians and vegans, the food produced by it is not rejected. This is certainly not least due to the fact that it would be very difficult to entirely do away with all foods produced in this manner. Interestingly enough, people who obtain a portion of their vegetables from farmers who farm exclusively with plants, report that these products are considerably tastier than their counterparts. Reduced overfertilization may explain this, allowing the plants more time to grow. For as long as practicality (as well as cost) does not allow for a diet consisting of strictly plant-grown crops, most vegetarians and vegans will continue to be forced to make concessions in this regard. For the farmers a market, rarely cultivated today, lies fallow.
As a first step towards a more natural and environmentally friendly agriculture, a discussion on animal fertilizers would be much welcome.

Organic vegetables from slaughterhouse waste?

Some organic organizations recommend blood meal, bone meal and even entrails from slaughtered animals as fertilizers in order to maintain the “natural cycle”. This approach has always been problematic as there are certain animal pathogens that can survive in the soil for a long time. Yet mad cow disease has made this practice even more questionable. Swissveg has clarified (as of the beginning of Dec. 2000):
Bio-Suisse (the “Knospe” label) still allows all animal fertilizers, i.e.: meat meal, blood meal, feather waste, hair meal, horn meal as well as liquid manure and manure. However, (liquid) manure is only rarely used in organic vegetable growing. Fertilizers made from slaughterhouse waste are derived from conventionally kept animals. However, this fertilization practice is soon to be reconsidered, as attitudes among the population have changed significantly due to BSE.
The biodynamic Demeter farms, which in practice also always include animal husbandry, previously recommended all the above animal fertilizers. Fortunately, this changed in1997: Blood and bone meal has since been banned in all biodynamic farms because of the risk of BSE. Nonetheless, fertilizers made from pure horn substance, hair and feather waste are still allowed today.
The situation is different in the case of the German organization “Bioland”: Blood meal and bone meal are still permitted fertilizers there.

Renato Pichler

  2. An exception in Switzerland is the «Bliib Gsund»-Nature-Distributor with their online-shop: and in Germany:
  3. 90% der Schweizer Kälber erhalten Antibiotika
  4. Neue Zürcher Zeitung, Forschung und Technik, 28.2.2001: Antibiotika allüberall
  6. Bioveganer Landbau
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