Australian beef cattle turn low-quality feed into lots of high-quality protein for human nutrition.

Have you noticed more friends and family making food choices based on what they think is best for the planet? 

Red meat is often criticised as having a very large footprint. One argument is that beef cattle take up land where crops could be grown for human food. Or that cows are eating grain that humans could be eating instead. This is traditionally known as the ‘food versus feed’ debate‘. But this new research provides a different perspective on protein supply.

Animal production systems differ widely across the globe in their sources of feed and competition with humans for food. We wanted to test the assumption that beef cattle production in Australia was inefficient. We found typical Australian beef production creates high-quality protein for humans. And they don’t compete with us for food.

The work gives our red meat industry a benchmark for the first time. And it paves the way to better understand efficiencies in other protein production systems.

Visual representation of the net protein contribution score.
Our net protein contribution (NPC) score of typical Australian beef systems.

Net protein contribution

In our study, we used a relatively new concept called ‘net protein contribution’ or NPC. This looks at the amount and quality of human-edible protein an animal production system consumes compared to what it contributes to the human nutritional supply. A number greater than one means a positive contribution.

Beef cattle in Australia start off grass-fed, grazing on pasture that farmers may supplement with grains or hay in times of shortage. About 50 per cent stay grass-fed their whole lives. The other 50 per cent spend most of their lives on grass. Then they move to a period in feedlots to bring them to market weight faster. This is also known as finishing. There they’ll typically receive some grain that humans could also eat.

Our research shows typical Australian grain-fed, or grain-finished, beef has a net protein contribution of 1.96. In other words, they create almost twice the human-edible protein they consume.

Inedible feed to edible protein

The feedlot sector increasingly uses by-products that humans can’t eat, while still meeting the nutritional requirements of cattle. Examples include spent grain from bio-alcohol, feed-grade grain and cottonseed.

Grass-fed cattle (that may eat very small amounts of grain) produce almost 1600 times the human-edible protein they consume. Cattle that graze only on grass or hay their whole lives don’t eat any human-edible protein at all. Their net protein contribution to the human nutritional supply is so high it’s literally off the scale.

Moo-ve over! Cattle are experts at turning inedible protein into high quality protein for humans.

Proteins ain’t proteins 

What do we mean by ‘human-edible protein’? It is protein humans can choose to eat, like meat or wheat, for example.

Proteins are made up of amino acids. The different protein types contain different amino acids, some of which are essential to human nutrition. The Food and Agriculture Organization of the United Nations has assigned scores to food proteins. They base the scores on the amino acid balance, digestibility and ability to meet human nutritional requirements.

So, not only do cattle create more protein than they consume. They turn low-quality proteins from a human nutritional perspective into high-quality protein with a more balanced amino acid profile.

Upscaling protein

To apply NPC to typical Australian beef enterprises, we used our model of ruminant grazing systems, GrassGro. We took the UN’s protein scores into account along with real-world inputs and outputs of beef enterprises. These included methane emissions, historical climate records and grain-based commercial feedlot diets.

Based on this, we found beef supply chains in Australia are efficient at turning a diet that contains very little or low-quality protein into lots of high-quality protein that meet human nutritional requirements.

The methane story

The microbes in a cow’s stomach turn indigestible cellulose from grass and hay into human-edible protein. Unfortunately, they are also the culprits when it comes to methane output.

Methane emissions from Australia’s ruminant livestock are currently 9.5 per cent of our total greenhouse emissions. We’re helping the sector move to being carbon neutral by 2030. This includes ideas like feeding seaweed to cows to reduce their methane emissions by about 80 per cent.

We’ve studied how much methane different systems produce. On average, grain-finished beef generated 30 per cent less methane per unit of beef than grass-fed. This difference is largely because grass-fed animals grow more slowly, so they’re on the planet longer. It shows that if you take sustainability into account in your food choices, the picture can be complex.

Not competing for land

Part of the efficiency equation for Australian beef is that cattle mainly graze on land we can’t grow crops on. This is because of its terrain or soil type. In fact, Australian Bureau of Statistics’ land use data show that since 2010 less than four per cent of Australia’s agricultural land is used for growing crops.

A cow needs to eat around 25 kilograms of feed to produce one kilogram of beef. But us humans can eat none or only some of that 25 kilograms. So in terms of human-edible protein – one kilogram in and 1.96 kilograms out – the perspective looks quite different.

All up our work suggests that cows can be a good use of agricultural land for contributing valuable protein to our food supply.

This research was undertaken as part of our Future Protein Mission. The Mission aims to improve the productivity and sustainability of new and existing Australian protein industries through science, innovation and technology.


  1. The logic with cattle produced methane is wrong. it is no different to using biofuels in motor vehicles but with an 8 year time constant. The methane is already in the atmosphere from the cattle and it breaks down to CO2 in 8 years. The CO2 is photosynthesised back to feed. No further methane is generated unless there is an increase in production numbers. It does not contribute 9% to our greenhouse gases. With constant numbers reducing methane from cattle is a GHG sink.

    1. But methane is not produced in batches, there is constant production at a daily basis from the industry. The data shows that methane concentrations in the atmosphere have been generally increasing for the past 2 centuries, clearly indicating that any offset in feed or other sources is not happening at the same pace. If not, there would be no interest in reducing methane production in the industry like what as discussed in the article.
      While there are other sources of methane that also should be considered in the broader scheme of things (e.g. the biofuels you mention) it’s a strawman to use that as a response to an article about beef production. Like CO2, anthropogenic production of methane has been increasing over time, with animal agriculture being the key driver.

  2. yes, i have followed the science but i think veganism is based more on ideology that science

    1. Agree veganism is a moral and ethical stance, nothing to do with health or the environment. But the totality of science seems to show that animal agriculture and consumption is bad for both.

    2. Just wondering who funds this research which I find very interesting as I have reduced my red meat consumption due to carbon footprint. Does this research or any of the researchers have any link to the cattle industry as I know this is what will be asked when I share it on my FB pages as I would like to . It would have been good to put this at the bottom of the article- I don’t think I saw it any where

      1. Hi Sue,

        This project was funded purely by CSIRO – namely, our Agriculture and Food business unit and our Future Protein Mission. The red meat industry didn’t fund this work. There is a funding acknowledgement in the paper itself, rather than in this article.

        Our researchers are experts in livestock science for the red meat industry. CSIRO has been working with the livestock and other traditional protein industries such as the grains sector for over 100 years.

        We’re glad you found this work interesting.

        Team CSIRO

  3. It’s all a matter of perspective. From your information we could also say; if Australia stopped using ruminant animals for food we would cut 9.5% of our total greenhouse gas emissions and, if we stopped raising animals for food we could return up to 96% of agricultural land to its natural eco-system.

    1. Efficiency – The concerns on inefficiency of beef is not rooted in protein, it is about grazing land, water use, feed input quantities and most of all, the opportunity costs. By sole focusing on the protein production, the findings appear to promote some sort of confirmation bias. The low proportion of land required for growing crops demonstrate that from total food production perspective (not focusing on protein), beef production is highly inefficient relative to crops.

      Comparing proteins – the article compares protein quality between beef and the crops used for feed. Consideration should be given to the protein from beef compared to the opportunity cost of other foods that provide similar or better proteins based on total protein quantity and amino acid profile. It’s weird to compare protein from beef with feed, which would not by itself represent a food choice for humans, Why not compare the inputs and protein outputs of beef production with alternatives that represent food choice e.g. soy, legumes, etc? And again, there is a skewed focus on protein. The ‘high-quality’ protein from beef is packaged with saturated fat, trans fat and cholesterol that raise serum LDL and lead to heart disease.

      Methane production – In terms of efficiency, would like to see the costs of beef production from an emissions perspective and the reduction from new feed technologies, perhaps capturing the time/costs for practice-change.

      Land-use – if such little proportion of land is required for crop production thus far, why would the suggestion be that beef production yield positive outcome? Wouldn’t it make more sense to then deemphasize the need for agricultural land, reducing opportunity cost for loss biodiversity?

      Overall, like any research, this work seem to be done within a finite scope but the article uses the narrow scope of findings to make overzealous claims about efficiency of beef production.

      1. Its not the cow, it’s about the how. How we farm. Holistic grazing practices improve water content, carbon storage and regenerate pastures. Humans need to stop blaming ruminants for the damage to our climate, it’s us and how we use the Earth to get what we want, we live seperately from the natural world, that is the issue.

    2. Kangaroos are ruminants too! Do we kill them off as well?

  4. I’d like to know if you factored in the transportation (road, etc) into the carbon emissions calculation both from the perspective of transporting live cattle and from the abattoir to wholesalers/grocery stores. As an example, locally transported meat is often magnitudes higher than fruits/vegetables shipped via sea.

  5. Great to see some data around this subject. It’s always made intuitive sense but because so much of the criticism of beef consumption has been based on data from US where corn is subsidised and lot fed beef production is s.o.p., it’s been hard to defend Australian beef. Factor in the role of well managed range-land cattle in carbon cycling & sequestration and fuel load reduction for fire hazard management and cattle start looking pretty good. Plus grass fed beef wins on flavour every time.

What do you think?

We love hearing from you, but we have a few guidelines.