Should We Be Eating The Food We Feed To Livestock?
Why do we feed farm animals food that humans could eat? Wouldn’t we be better off if we just ate those crops ourselves?
When 14% of the world’s humans go hungry, how can we allow so many human-edible crops to be fed to livestock? These are all great questions that I am excited consumers are asking. I’ve said many times that hunger is the world’s stupidest problems because, even in developing countries where agriculture has lagged behind technological innovations, enough food is still produced for every single person to consume over 2,500 calories every day. So why don’t people get enough food? |
The answer, of course, is food waste. And many plant-based advocates have tried to suggest that feeding crops to livestock is just as wasteful as throwing it in the trash can.
The truth, however, is that we actually get more nutrients by eating the animals that eat the crops than by just eating the crops directly.
Feed to Gain Ratios
Many complain about the inequity of the feed : gain ratio of livestock animals. Basically, farm animals have to eat a certain number of pounds to gain one pound of weight.
For example, beef cattle have to eat six pounds of feedstuffs to gain one pound of body weight (6:1). This is much higher than other species. For example, sheep and swine are 3:1.
So does this automatically mean that we should be eating everything that the farm animals are eating and just cut them out of the picture? Wouldn’t that simply multiply our food production by 3 or 6?
The truth, however, is that we actually get more nutrients by eating the animals that eat the crops than by just eating the crops directly.
Feed to Gain Ratios
Many complain about the inequity of the feed : gain ratio of livestock animals. Basically, farm animals have to eat a certain number of pounds to gain one pound of weight.
For example, beef cattle have to eat six pounds of feedstuffs to gain one pound of body weight (6:1). This is much higher than other species. For example, sheep and swine are 3:1.
So does this automatically mean that we should be eating everything that the farm animals are eating and just cut them out of the picture? Wouldn’t that simply multiply our food production by 3 or 6?
What Are Livestock Really Eating?
Obviously, it's not that simple. Let’s look at cattle, which seem to be the worst-case scenario. A journal article from the University of Florida put it really well: “Beef production systems primarily bring value to society by providing a source of high-quality nutrients in a form that people have a strong desire to consume. Cattle do this by consuming diets (forages and byproducts) whose nutritional value is largely unavailable to humans. Cattle are upcyclers of protein, transforming low-quality or human-inedible proteins and converting them into beef, a high-quality protein source.” Wickersham, Tyron, and Jason Sawyer. “Protein Supplementation of Beef Cattle to Meet Human Protein Requirements.” UF IFAS, University of Florida, 2017. |
This nutritional value that is unavailable to humans includes grass, roughages (like hay), and inedible byproducts. We can’t just eat the things that livestock are eating… our digestive systems are very different from a ruminant’s, and things that are nutritious to them are often toxic to us.
Even grain-fed cattle eat exclusively grass for the majority of their lives. The reality of our beef production systems in the developed world is that the typical beef steer lives the first year to year and a half of his life on a pasture never coming into contact with grain. Then he will spend the last few months before he is slaughtered in a feedlot where he will be fed grain supplements to be “finished” with higher protein-concentrate feedstuffs.
So, a rational consumer might wonder, is this the part we should cut out? Does grain-finishing beef cattle reduce human-edible calorie production?
What’s In Livestock Grain?
It’s important to detour for half a second to realize that a very small proportion of the grain livestock consume is made from crops that humans can actually eat. So not only are the cattle eating grain for only a small fraction of their lives, but the grain they eat still does not contain many materials that a person could just walk up and chomp on.
As I explored in an earlier blog post, well over 90% of the ingredients in livestock grain are byproducts of food processing such as cottonseed or soybean meal. These are created as a result of the production of products we do use—such as soy tofu or t-shirts—but, after the usable materials are extracted, the leftovers are not safe for humans to eat.
Even grain-fed cattle eat exclusively grass for the majority of their lives. The reality of our beef production systems in the developed world is that the typical beef steer lives the first year to year and a half of his life on a pasture never coming into contact with grain. Then he will spend the last few months before he is slaughtered in a feedlot where he will be fed grain supplements to be “finished” with higher protein-concentrate feedstuffs.
So, a rational consumer might wonder, is this the part we should cut out? Does grain-finishing beef cattle reduce human-edible calorie production?
What’s In Livestock Grain?
It’s important to detour for half a second to realize that a very small proportion of the grain livestock consume is made from crops that humans can actually eat. So not only are the cattle eating grain for only a small fraction of their lives, but the grain they eat still does not contain many materials that a person could just walk up and chomp on.
As I explored in an earlier blog post, well over 90% of the ingredients in livestock grain are byproducts of food processing such as cottonseed or soybean meal. These are created as a result of the production of products we do use—such as soy tofu or t-shirts—but, after the usable materials are extracted, the leftovers are not safe for humans to eat.
It's important to realize that, even if there were not a single farm animal in all of the world, these byproducts would still be produced and we, the humans, would have no other use for them. These byproducts would become waste-products. Farm animals can consume them, however, and then we can eat the farm animals that turn those inedible byproducts into human-edible calories. Livestock don’t steal our food… they make it go farther.
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If you had any doubts about just how prevalent these human-inedible byproducts are in livestock grain, you’ll be as shocked as I was to learn that a single byproduct, soybean meal, represents two-thirds of the protein in livestock grain around the world.
However, there are still some feedstuffs, mainly corn, that are consumable by humans but are still fed to livestock. Why?
The Great Corn Debate
Cooperative Extension had a great post where they broke down how 6 pounds of corn is used to produce 1 pound of beef. This may sound like an inadequacy in favor of cutting out red meat, but let’s look at the nutritiousness of each product. One pound of beef produces 119.43 grams of protein, whereas 6 pounds of corn produces 87.63 grams of protein. This means that we get 36% more protein from corn fed to livestock than from eating the corn ourselves.
In October of 2018, the scholarly journal, Translational Animal Science, published a study that looked at the inputs versus outputs of human-edible protein in beef production systems. What they found is that the amount of human-usable protein that beef cattle eat, regardless if they’re grass-fed for their entire lives (meaning they never ate any feedstuffs that humans can get usable calories from) or consume grain, is less than the amount of human-usable protein we get in the form of beef. Here’s what they said:
“A model was developed to estimate beef’s contribution toward meeting human protein requirements using a summative model of net protein contribution (NPC)…. NPC was calculated by multiplying the ratio of human-edible protein (HeP) in beef to the HeP in feedstuffs by the protein quality ratio (PQR)…. An NPC > 1 indicates that the production system is positively contributing to meeting human requirements…. NPC for the entire beef value chain was above one for all scenarios, indicating each scenario was positively contributing to human protein requirements. Although the feedlots were in competition with humans for HeP, it was outweighed by the stocker and cow–calf sectors’ ability to positively contribute to the human food supply by using less HeP and improving the protein quality.”
Baber, Jessica R, et al. “Estimation of Human-Edible Protein Conversion Efficiency, Net Protein Contribution, and Enteric Methane Production from Beef Production in the United States .” Translational Animal Science, vol. 2, no. 4, Oct. 2018, pp. 439–450.
However, there are still some feedstuffs, mainly corn, that are consumable by humans but are still fed to livestock. Why?
The Great Corn Debate
Cooperative Extension had a great post where they broke down how 6 pounds of corn is used to produce 1 pound of beef. This may sound like an inadequacy in favor of cutting out red meat, but let’s look at the nutritiousness of each product. One pound of beef produces 119.43 grams of protein, whereas 6 pounds of corn produces 87.63 grams of protein. This means that we get 36% more protein from corn fed to livestock than from eating the corn ourselves.
In October of 2018, the scholarly journal, Translational Animal Science, published a study that looked at the inputs versus outputs of human-edible protein in beef production systems. What they found is that the amount of human-usable protein that beef cattle eat, regardless if they’re grass-fed for their entire lives (meaning they never ate any feedstuffs that humans can get usable calories from) or consume grain, is less than the amount of human-usable protein we get in the form of beef. Here’s what they said:
“A model was developed to estimate beef’s contribution toward meeting human protein requirements using a summative model of net protein contribution (NPC)…. NPC was calculated by multiplying the ratio of human-edible protein (HeP) in beef to the HeP in feedstuffs by the protein quality ratio (PQR)…. An NPC > 1 indicates that the production system is positively contributing to meeting human requirements…. NPC for the entire beef value chain was above one for all scenarios, indicating each scenario was positively contributing to human protein requirements. Although the feedlots were in competition with humans for HeP, it was outweighed by the stocker and cow–calf sectors’ ability to positively contribute to the human food supply by using less HeP and improving the protein quality.”
Baber, Jessica R, et al. “Estimation of Human-Edible Protein Conversion Efficiency, Net Protein Contribution, and Enteric Methane Production from Beef Production in the United States .” Translational Animal Science, vol. 2, no. 4, Oct. 2018, pp. 439–450.
The University of Florida article I mentioned earlier had similar conclusions:
“Even when corn is fed at 120% of the level reported by Peters et al. (2014) beef still represents a breakeven proposition on a net protein contribution basis…. Ruminal microbes can transform low-quality sources of protein into a much more valuable source of indispensable amino acids…. Upcycling of low-value or inaccessible sources of protein into a high-quality source of human edible protein is truly remarkable, and an essential component of meeting the increasing demand for high-quality sources of human-edible protein.” |
Notice their emphasis on not just the quantity of protein, but also the quality. Your body does not absorb 100% of the protein you consume. The Journal of Nutrition published a 2015 study that reported that animal-based protein sources are over 90% digestible. However, they said that plant-based counterparts, are, at best, 80% digestible, but usually closer to 45% of the protein in plant products actually gets absorbed by human intestines.
The researchers attributed this difference to, among other things, a component of plant proteins called urea. The human digestive system cannot derive the amino acids out of urea, but livestock animals can. In general terms, cattle change the protein into forms of amino acids that our own digestive systems can more-easily use.
Let’s apply this phenomenon to our earlier comparison of the protein from one pound of beef to six pounds of corn. 90% of the 119.43 grams of protein gives us 107.49 grams of protein from one pound of beef that our bodies can digest. On the other hand, if we take an average of those plant-based nutrients and say that 63% of protein from corn is usable, we see that the six pound of corn we fed to livestock would only afford us 55.21 grams of digestible protein.
This means that we get 94.7% more usable protein from corn that’s fed to livestock than from corn fed to people.
The researchers attributed this difference to, among other things, a component of plant proteins called urea. The human digestive system cannot derive the amino acids out of urea, but livestock animals can. In general terms, cattle change the protein into forms of amino acids that our own digestive systems can more-easily use.
Let’s apply this phenomenon to our earlier comparison of the protein from one pound of beef to six pounds of corn. 90% of the 119.43 grams of protein gives us 107.49 grams of protein from one pound of beef that our bodies can digest. On the other hand, if we take an average of those plant-based nutrients and say that 63% of protein from corn is usable, we see that the six pound of corn we fed to livestock would only afford us 55.21 grams of digestible protein.
This means that we get 94.7% more usable protein from corn that’s fed to livestock than from corn fed to people.