Press release Which farm animals live off more human edible protein than they consume? Edible protein efficiency of Belgian livestock systems calculated for the first time

grazing cows

The Belgian Feed Association (BFA), in collaboration with ILVO, has announced the results of a study into the edible protein efficiency of Belgian cattle. The ILVO study (in Dutch) maps for the first time the ratio between on the one hand the vegetable proteins used as animal feed, and which in principle could also be used in human food, and on the other hand the amount of edible animal protein (such as meat, eggs and milk) that is balanced.

The ILVO study shows that cattle that eat a lot of grass are net producers of edible human protein. They produce more edible protein in the form of milk or meat than they consume. For pigs and laying hens, the figure is close to break-even (they consume about as much human edible protein than they provide in the form of pork or eggs). 'Broilers currently appear to consume more human edible protein than they give back, mainly because their feed contains a lot of grains,' says Leen Vandaele, senior researcher ILVO.

Katrien D'hooghe, managing director of BFA: 'As the umbrella organization for animal feed companies, we wanted to know what the situation was in our country regarding the protein competition between humans and farm animals. We find it our task to know these figures, and to strive for an even better return in this area, so that less food for humans has to go to an animal. That fits in with our roadmap to further reduce our sector's impact on the environment and food chain.'

BFA makes the case that by 2030, the livestock feed sector can source half of its feed from circular by-products that are no longer suitable for human consumption, up from 43% today. In addition, the sector wants to use even more protein sources that are not consumed by humans, such as rejected peas, lupin and insect meal, for example.

French methodology used for calculating edible protein efficiency of animal production in Belgium

Verschillende onderzoeksgroepen uit het Verenigd Koninkrijk, Oostenrijk en Frankrijk werkten al aan een methodologie om de competitie voor plantaardig eiwit tussen dieren en mensen wetenschappelijk te beoordelen. Carolien De Cuyper (ILVO dier- & voederexpert): ‘In ons vak is de berekening van bruto eiwit efficiëntie goed bekend. Daar stellen we de vraag: hoeveel eiwit wordt geproduceerd door de dieren ten opzichte van de hoeveelheid eiwit die ze consumeren? Landbouwdieren kunnen in hun rantsoen echter zowel plantaardig eiwit hebben dat zij alleen verteerd krijgen, als plantaardig eiwit dat ook in menselijke voeding (direct of na bewerkingen) terecht kan. De berekening van de eetbaar eiwit efficiëntie is een innovatieve benadering die precies de competitie tussen dier en mens voor eetbaar eiwit becijfert.”
Several research groups from the UK, Austria and France were already working on a methodology to scientifically assess the competition for plant protein between animals and humans. Carolien De Cuyper (ILVO animal & feed expert): "In our profession, the calculation of gross protein efficiency is well known. There we ask the question: how much protein is produced by the animals compared to the amount of protein they consume? However, the rations of farm animals can have both plant protein that only they can digest, as well as plant protein that can also end up in human food (either directly or after processing). The calculation of edible protein efficiency is an innovative approach that precisely quantifies the competition between animals and humans for edible protein."

Within this study, ILVO mapped what the animals use in edible protein (based on feed composition) and produce in edible protein (their total output as milk, eggs, meat) for the commonly used animal production systems in Belgium (pig, laying hens, broilers, dairy cattle and beef cattle). For the inputs, the researchers worked on the basis of the feed compositions. To determine the edible protein content of each of the different raw materials, they relied on a French study, which had previously worked out a list of the percentages of human edible protein per feed ingredient.

'Then, for each production system, we were able to determine the ratio of the human edible animal protein produced to the human edible protein consumed by the animals and thus obtained the edible protein efficiency per animal species and feed system,' says De Cuyper.

If the score is clearly lower than 1, then the animal is a net consumer of -human edible protein. If the value is greater than 1, then more humane edible animal protein is produced than edible plant protein was used for. In that case, the animal is making a positive contribution to the production of protein for human consumption.

Research results show decent edible protein efficiency

The edible protein efficiency for the cattle sector is considerably greater than 1. This means that the cattle sector is a net producer of edible protein. In other words, the cattle valorize many proteins that cannot be eaten by humans. The extensive cattle system scores the highest in edible protein efficiency for both meat and dairy cattle because of the large proportion of roughage and especially grass in the animals' rations. Pigs and laying hens have an edible protein efficiency just below 1. These animal species are narrowly considered net consumers of edible protein. 'There is a clear logic: as more raw materials with a low proportion of edible protein are fed, the pig and poultry sector can also make a positive contribution to the production of edible protein,' says Leen Vandaele (senior ILVO animal researcher).

Net contribution of Belgian livestock to human protein supply. (ILVO study of C. De Cuyper, et al., 2022)Edible protein efficiency

Fattening pigs

Dairy cattle kept intensively, with maize-rich feed1.22
Dairy cattle kept intensively with grass-rich feed1.71
Dairy cattle kept extensively with grass-rich feed3.13
Beef cattle kept extensively with grass-rich feed1.34
Beef cattle kept intensively with maize-rich feed 0.93

Four side notes

This study takes a closer look at only one aspect of sustainability. There are many other important and influencing parameters such as enteric emissions, land use, carbon storage, value of animal manure, ... that need to be taken into account to paint a more complete picture of the sustainability of livestock farming.

The final scores in this study are a rough estimate, in that the final nutritional quality of import and export proteins was not weighed. Nutritionists know, however, that plant and animal proteins are not entirely equivalent. Plant proteins provide limitations for humans in terms of amino acid profile, and sometimes contain anti-nutritional elements. Animal proteins (dairy, eggs, meat) have a higher digestibility, absorbability and contain all essential amino acids for humans.
The edible protein content of wheat was deeply considered in this study. The French study assumes for wheat that it is baking grade wheat. Wheat fed to farm animals does not meet that standard.

Katrien D'hooghe (BFA). "That's why we made a nuance on the competitive nature of feed wheat. Feed wheat, not baking wheat, is used in Belgian cattle feed rations. Feed wheat is considered by the food industry as not processable for human application. We asked to calculate the following hypothesis: Suppose you were to calculate the edible protein efficiency score using the edible protein contents of feed wheat (i.e., a coefficient adjusted to Belgium), what then? It turns out that the edible protein efficiency then comes to 1.36 for fattening pigs, 0.96 for broilers and 1.30 for laying hens. Then pigs and poultry are net producers of edible protein. For cattle this is less of a factor, as grains do not play a major role in cattle rations.

We had another second calculation made to include the factor 'whey'. In cattle rations, this is a by-product from the dairy sector used in France, an animal protein source and an important feed raw material that is not on the list of vegetable protein raw materials (editor's note: This by-product of whey is the so-called feed grade whey powder and skimmed milk powder, which are not used for human consumption). After this reconsideration, in dairy cattle the edible protein efficiency on the intensive corn-rich ration, intensive grass-rich ration and the extensive ration increases to 1.26, 1.81 and 3.59, respectively, and in beef cattle to 1.72 and 1.09 respectively."

Net contribution of Belgian livestock to human protein supply. (ILVO studie C. De Cuyper, et al., 2022)

Edible protein efficiency
(Belgian corrected edibility list )

Fattening pigs

Dairy cattle kept intensively, with maize-rich feed1.26
Dairy cattle kept intensively with grass-rich feed1.81
Dairy cattle kept extensively with grass-rich feed3.59
Beef cattle kept extensively with grass-rich feed1.72
Beef cattle kept intensively with maize-rich feed 1.09


Katrien D'hooghe, managing director BFA: "This study confirms that the choice of raw materials and the valuation of the edible protein content strongly determine the edible protein efficiency of Belgian cattle. It strengthens us in our conviction that we must maximize the use of side streams from food and biofuel production. In this way, we maximize our commitment to a circular production system. After all, we cannot eat products such as beet pulp, beer marc, etc. ourselves. Currently, 43% of our raw materials are already such by-products. By 2030, this should be 50%. We are also continuing our search for alternative proteins, such as peas, field beans and insects. With an extra focus on avoiding competition between protein for animal feed and protein for human food. For the first time, we now have a clear picture of this."


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