From grass to nutrients, a journey into the cow's digestive system

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Extract of the talk given during The Soft Protest, re-chewing & Digest’s dinner
in October 2019 at Corridor project space in Amsterdam.

“The cow’s digestive system is a wonderful machine: it allows cows to get energy from an undisputed resource that humans can’t digest: grass. 1/4 of Earth’s land area being grasslands it allowed herds of ruminants to thrive across the Old World, even before mankind domesticated them.

Grazing consists on wrapping the tongue around plants and pulling to tear it — this is the entry that let us access grass energy in the form of milk and meat. Once the tongue swallowed the grass, it ends up in the rumen, the first stomach compartiment, field with the precious microbial fauna allowing recalcitrant plants fibres to be proceed through fermentation. While the liquid portion of food moves from the reticulum to the other compartiments, the solid portion stays in the rumen. It may then be propelled up by the oesophagus to be chewed again, before to be swallowed again: this is ‘rumination’. After grass passed through the 4 compartiments, all nutrients obtained are absorbed in the intestine.

This process unfortunately produces a greenhouse gas called methane, resulting from fermentation in the rumen. If we combine feed production, grass digestion, animal waste, and land-use change, livestock farming accounts for 14,5% of global man-made greenhouse gas. But methane being more potent than carbone dioxyde, cattle is considered to be responsible for 30% of global methane emission. With 1 billion animals worldwide, cattle farming is an over-size industry, relying on huge amounts of exported feed, resulting on an excessive production of manure and methane per hectare of land.

If we were to reduce the world’s herd for the good of the environment, it is safe to say that smaller quantities of meat would be available for consumption. One solution could be therefore to re-introduce parts of the animal which are, in countries like the Netherlands, considered like bi-products: e.g. intestins, stomach, tongue, etc… In many neighboring countries, such parts are still eaten, making use of the cow in its entirety as well as of the veal (which has to be slaughtered every year, to allow the cow to produce milk).”

Exhibition of the cow’s digestive system

To illustrate our talk on the cow’s digestive’s system as well as the use in cooking of what is often considered as “by-products” (ergo: tongue, tripes, stomach, etc.) of the meat and dairy industry, ceramist Denise Aimee Rijnen (Darc matter ceramics) produced two custom platters for a veal tongue and its digestive system. These plates were exhibited during the following week as part of the exhibition and transformed again into raw clay.[1]

Related dish


  1. The platters had not been fired on purpose to allow them to be recycled.