The ‘Bull About Cows’

David Hunt, Co-founder and chief strategy officer Cainthus

Throughout history there have been three agricultural revolutions, from domestication to industrialization and on to intensification (The Green Revolution). Now in the 21st century we are witnessing the fourth agricultural revolution – the digitization of farming.

David Hunt is co-founder and chief strategy officer for Cainthus

This digital farm revolution is presenting many new ways to produce and enjoy food while also striving to undo some of the unintended and damaging consequences of the green revolution which saw the introduction of high yielding seeds, an increased use of fertilizer, herbicides and pesticides as well as a move away from small holder farm models that utilized crop rotation and integrated livestock.



While the Green Revolution gave us a super abundance of food, one of the biggest learning points has been that replacing the old system entirely was a mistake, and this can be addressed in this new digital agriculture.

In August this year the IPCC (Intergovernmental Panel on Climate Change) published their report which strongly advocated for agro-ecological food production systems, diverse and nutritionally balanced diets, no over-consumption, and waste mitigation.


One interpretation of these findings has been to advocate for plant-based diets, but when you read the report it demands ecological sustainability for both crop and animal production and advocates for a balanced diet that includes animal protein. The important role that cows play in up cycling waste materials into some of the best sources of animal protein a human can put in their bodies is crucial for a sustainable food system; a story less told. So, in the spirit of balance, let’s take a moment to clarify their five charges about cows:

Claim 1: It takes ~15,000 litres of water to make 1kg of beef/milk

Reality: 97% of water consumed by cows is ‘green water’ or rainwater and it’s almost entirely from the plants the cows eat rather than direct intake. ‘Blue water’ or drinking water accounts for just 1.1% of their intake while the remainder is service water to clean facilities and feed mix water. Rain falls where it falls regardless of human intervention and we are not in a situation where this rainwater can be re-purposed to fall somewhere more convenient. The argument that you could use this rain to grow crops for human consumption does not really apply to cows as only ~13% of their diet is grain, the rest is agricultural waste streams and grass.

The fact remains that the water use of milk is extremely comparable to most plant proteins. Beef remains water intensive, but not as bad nuts or fruits on a L/gram of protein basis.

Source: Mekonnen and Hoekstra (2010)

It’s also worth noting that human nutrition is not based on weight of food or calories, it is based on the nutritional content of the food and its bioavailability. If we are to replace dairy/beef protein and fat with plant sources, then we need to compare them with plant sources on this basis as we best can. It is hard to do this because:

  • Different production systems for plants and animals result in very different numbers

  • Animal protein is not directly comparable to plant protein as it has amino acids and vitamins key for human development that cannot be found in sufficient concentrations in plants.



Claim 2 : Cows are eating all our grain

Reality: Cows are not just beef and dairy. They are a symbiotic part of the global Ag system that takes waste from other areas of food and agriculture and upcycles them into highly digestible protein. A typical cow’s diet is only 13% grains, and cows do not really compete with humans for food as 86% of the global livestock feed intake in dry matter consists of feed materials that are not currently edible for humans.

The principle consumers of grains globally are poultry, pigs, and fish. Cows mostly eat grass, leaves and waste. When this is considered, 1 kg of meat requires ~2.8 kg of human-edible feed for ruminants and 3.2kg for monogastrics. If we look at specific crops, in the US cows consume ~9% of annual soybean usage (pigs & poultry are 82%). For corn, cows consume 14%, with humans the highest consumers at 48% (38% ethanol, 10% food).


Claim 3: Cow related emissions are greater than emissions from all transport.

Reality: This belief first arose in a paper from 2006 called Livestock’s Long Shadow. This paper estimated livestock emissions as 18% of the global total vs transport at 14%. Several errors were pointed out in this number, chiefly that it used a full life cycle analysis for livestock, but only looked at tail pipe emissions for transport. On a like for like basis, it is estimated that livestock emissions are actually 5% vs 14% for transport.

Emissions associated with cattle fail to account for the fact that cattle in pasture environments sequester a lot of carbon. On a net basis, it is possible to produce beef and dairy on a negative carbon basis through regenerative agriculture. The problem is not the cows, rather how they are being used. While cows are a material source of methane emissions globally, it is estimated that grazing cattle can sequester up to 3 tonnes/acre/year.

Methane emissions associated with cows are not an unsolvable problem. New products and methodologies from feed additives to gene editing entering the market are dramatically reducing methane emissions associated with cows. Some studies are showing a 30% reduction in emissions if cows eat certain feed inputs, and we have also isolated some of the genes causing methane production, enabling manipulation via selective breeding and gene editing.

In fact, emissions associated with cows should make us excited about our potential to use ruminants as a carbon sink that produces food while enriching its environment.

Claim 4: Livestock use ~ 80% of agricultural land but provide only 13% of calories

Reality: It is possible to hit your daily calorific intake and to die of malnutrition.  Like the arguments made in relation to water and cows, calories are an inappropriate measurement unit to use as it takes no account of nutrition requirements. Our entire agricultural system is built around rewarding production of weight and calories, rather than an ability to produce nutrition. If you look at them in terms of nutrition, the picture is very different.

Additionally 66% of the 2.1bn hectares used for livestock production can only be used as ruminant pasture, making beef and dairy look more sustainable still as there is no alternative use for this land. Either it is used for ruminant food production or it is wilderness. It is not possible to replace it with crop production.

Land Use per unit protein.PNG

The chart highlights that dairy has a better footprint than barley without even considering amino acid profile, B12, and availability. For beef, mutton, and goat meat, please recall that 66% of the land mentioned here cannot be used for anything else.

There are many claims that vegetarian diets will result in lower land use for agriculture, but these claims are largely based on the incorrect assumption that food edible by livestock is directly edible by humans, or that land used by livestock could be used for human food.

 A 2017 study examined what the USA would look like without animals. Its chief finding was that the US would have 23% more food by weight but would suffer from malnutrition. Like most things in life, it seems a balanced approach is better. North America and Australia need to eat less animal protein while sub Saharan Africa need to eat more.

Claim 5: We are deforesting the planet to create pasture for cows.

Reality: This belief is most commonly voiced in conjunction with concerns about the Brazilian rainforest and makes a degree of sense given that Brazil has developed into a major global beef exporter. However, between 2000 and 2016 global pastureland reduced by 140m hectares while demand increased strongly, a remarkable achievement by farmers.

While deforestation is still a major global problem and still happens for pasture creation, over the last 25 years it has been marginal (with Europe and North America even demonstrating reforesting). And when it comes to cattle, their role in deforestation is often misunderstood.

“Typically, the deforestation process starts when roads are cut through the forest, opening it up for logging and mining. Once the forest along the road has been cleared, commercial or subsistence farmers move in and start growing crops. But forest soils are too nutrient-poor and fragile to sustain crops for long. After two or three years, the soil is depleted. Crop yields fall. The farmers let the grass grow and move on. And the ranchers move in.” – FAO

Cutting down forest for either pasture or cropland is completely indefensible in the modern era, but it does appear that cattle farmers are getting outsize blame for their role in this. Brazil could double its beef output without cutting down a single additional tree simply be adopting more intensive production practices like the USA; deforestation of the Amazon is largely a soci-political issue rather than a bovine one.

This article is not intended to absolve cows of blame. Rather, it is to highlight that cows are an important part of the incredibly complex system we call agriculture. The US dairy industry has reduced emissions by 50% while increasing productivity by 100% in less than 50 years and are a shining example to other industries of what can be achieved with new technologies and techniques. An ecologically sustainable agriculture system will need ruminants of some kind, until such a time as we can create an ecological substitute for them.

In terms of agriculture and food production it is easy to let the ‘bull about cows’ distract from much bigger problems including:

Agriculture is an incredibly complicated industry and narrowing focus rather than taking a systematic view will cause us to make things worse rather than better.

Let’s embrace this digital revolution. Let’s take the tools that work and make them even better. Let’s approach food production and choice in a balanced and sustainable way. Let’s learn from the past and build an agroecology that allows us to harmonize nature and nurture far into the future.

Editor’s note:  David Hunt is co-founder and chief strategy officer for Cainthus, a new firm developing facial recognition for herd management. David started his career as a corporate banker but had long been fascinated by the opportunities to exploit emerging technology in various agricultural areas, so in 2016 co-founded Cainthus. As a startup founder, David has led many different initiatives pivotal to building the company to where it is today. He now leads the company’s strategic focus.

David has provided consultancy for the Advanced Research Projects Agency of the United States Department of Energy on sustainable agriculture and the European Union Agriculture and Rural Development Cabinet on agricultural legislation and entrepreneurship. He is also an accomplished public speaker, chiefly discussing the intersection of technology and agriculture.

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