This is a follow-up to a comment I received on a previous post (thankful for the kindness of co-innovators).
The commenter did not identify themselves, I think it may be Professor Grant Schofield (@grantsnz), but I could also be wrong, in any event, they show a much more expanded knowledge of impacts of diet than I’ve had previously:
The WHO and FAO research seems to have started out with extreme claims, modelled on US feedlot practice and not adjusting for carbon sequestration and other offsetting advantages, and has then reduced these estimates in each new report.
There’s more at this comment as well.
More things they don’t teach us in medical school, which I think are still important to understand if we are going to recommend diets as more sustainable than others, without information behind those recommendations – we have to read more than the abstracts.
Feed and Land Use Modeling
This paper models the use of land and feed for animal agriculture and its efficiency in conversion to human food. These things can be quantified:
The ability and performance of different livestock species and production systems to transform feed into animal products is usually measured by the feed conversion ratio (FCR), the quantity of feed per unit of output (milk, meat or eggs)
FCR can be further broken down into FCR2 and FCR3, which are the amounts of human-edible feed products with or without soybean cakes (if those are assumed to be human edible – most soybean cakes in the world are used in animal feed currently).
Same goes for land use. Not all land currently used in animal agriculture can be converted to production of human food
This study finds that out of the total grassland area currently used by livestock, 684.9 million ha could be converted to cropland. That is equivalent to 14% of global agricultural land and half of global arable land, while the remaining 1.3 billion ha of pastures and rangelands can be considered non-convertible.
Different animals have different impacts
There’s an excellent discussion of the comparison between ruminants (cattle) and monogastrics (pigs) and their differing use of resources. Monogastrics are more efficient converters of feed, however they require higher quality feed compared to ruminants.
It’s more complex than (I) previously thought
Livestock consume about 6 billion tonnes DM as feed per year, of which 86% is made of materials that are currently not eaten by humans. In addition, soybean cakes, which production can be con- sidered as main driver or land-use, represent 4% of the global livestock feed intake. Livestock play a key role in the bio-economy by converting forages, crop residues and agricultural by-products into high-value products and services. The production of global feed requires 2.5 billion ha of land, which is about half of the global agricultural area. Most of this area, 2 billion ha, is grassland, of which about 1.3 billion ha cannot be converted to cropland (rangeland). This means that 57% of the land used for feed production is not suitable for food production.
This paper’s purpose does not include modeling of climate change impacts, consumer preference, or chronic illness impacts of animal/non-animal diets.
I’m interested in this because
- Climate change is a risk to human health.
- Climate change increases disparities because it disproportionally affects vulnerable populations.
- Diversity allows the human species to survive 🙂
Comments and additional teaching always welcome
I couldn’t find a conflict-of-interest statement. The authors’ affiliations are listed as
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Viale delle Terme di Caracalla, 00153 Rome, Italy
- Independent consultant, the Netherlands.
- Animal Production Systems group, Wageningen University , P.O. Box 338, Wageningen, the Netherlands.
Citation + Discussions on social media
Mottet A, de Haan C, Falcucci A, Tempio G, Opio C, Gerber P. Livestock: On our plates or eating at our table? A new analysis of the feed/food debate. Glob Food Sec [Internet]. 2017;14(Supplement C):1–8. Available from: http://www.sciencedirect.com/science/article/pii/S2211912416300013