View source for How much protein could ruminants produce without crops

{{minor|Ruminants include '''cows, buffalo, goats and sheep.'''}}

If ruminants were fed '''only grass''' (and not crops), how much protein could they produce globally?

==Answer==
<big>About '''7 grams''' of protein per day, per person globally, '''in total''' from all milk & meat from all animals.</big>

<small>
* '''Side note:''' If animals were also fed [[crop residues]] (i.e. the parts that humans can't eat), this number would go up to 12 grams/day protein.
* For comparison: '''Status quo:''' Currently 16 grams/day protein ([[Code:food2.sql|10g from milk + 6g from meat]]). Much of this comes from cows that are fed '''grains (and other crops)''' that [[plant-based food|humans could have eaten]].
</small>

<tab name='See calculations' collapsed>
{{minor|Click on parts of the equations for details.}}
{{dp
|pasture
|2.8 billion tonnes/year
|Dry mass of all grass & leaves, grazed from all pasture land
|Source:
<br />Breewood, H. & Garnett, T. (2020). What is feed-food competition? (Foodsource: building blocks). Food Climate Research Network, University of Oxford.
<br />Page 10
<br />References primary source:
<br />Mottet, A., de Haan, C., Falcucci, A., Tempio, G., Opio, C., & Gerber, P. (2017). Livestock: On our plates or eating at our table? A new analysis of the feed/food debate. Global Food Security.
}}

{{dp
|residues
|1.7 billion tonnes/year
|Dry mass of all crop residues, byproducts, and oilseed cakes except for soybean
|This should be, in principle, all the human-'''inedible''' parts of food crops (inedible due to being too fibrous; ruminants can digest the fiber and get calories from it).<br />Soybean meal is '''not''' counted here, because it '''can''' be turned into human food (soy flour).

Source:
<br />Breewood, H. & Garnett, T. (2020). What is feed-food competition? (Foodsource: building blocks). Food Climate Research Network, University of Oxford.
<br />Page 10
<br />References primary source:
<br />Mottet, A., de Haan, C., Falcucci, A., Tempio, G., Opio, C., & Gerber, P. (2017). Livestock: On our plates or eating at our table? A new analysis of the feed/food debate. Global Food Security. 
}}

{{dp
|conversion_ratio
|133
|Ruminants produce 1 gram of human-edible protein for every 133 grams of dry matter they eat. 
|Dry matter includes all materials eaten by ruminants (both human-edible and human-inedible).

Source:
<br />Mottet, A., de Haan, C., Falcucci, A., Tempio, G., Opio, C., & Gerber, P. (2017). Livestock: On our plates or eating at our table? A new analysis of the feed/food debate. Global Food Security. 
<br />The number is mentioned in the Abstract: https://www.tabledebates.org/research-library/livestock-our-plates-or-eating-our-table
}}

{{dp
|world.population
|8 billion
}}

{{calc
|pasture / conversion_ratio
|(grams/day per capita)(world.population)
||If ruminants were fed only grass
}}

{{calc
|(pasture + residues) / conversion_ratio
|(grams/day per capita)(world.population)
||If ruminants were fed grass ''and'' crop residues
}}

----
{{minor|Status quo for comparison:<br />Run [[Code:food2.sql]] with query''':'''}}
<syntaxhighlight lang='sql'>
SELECT SUM(protein_grams_per_day_per_capita) FROM summary
 WHERE Item="Meat, buffalo"
    OR Item="Meat, cattle"
    OR Item="Meat, goat"
    OR Item="Meat, sheep"
    OR Item LIKE "Milk%";
</syntaxhighlight>
Result: <code>15.8043445906667</code>
</tab>


==Transition==
In the above scenario, there would be '''fewer cows''' than the status quo. {{light|(Populations of other ruminants might be lower too.)}} To reach this, there is '''no''' need for mass culling; farmers would simply '''not breed as many''' animals{{x|for example, lower rates of artificial insemination until the population stabilizes. Note: The farmers who own ''grain-fed'' cattle would be the ones to reduce breeding rates, more specifically}}. For this to happen, the demand for milk & beef would need to be lower (i.e. people would eat more [[plant-based]]).


==See also==
* [[Abolish factory farms]]
* [[Livestock inefficiency]]<!--
* [[Land]] - pastures can't get any bigger without [[deforestation|destroying natural habitats]] {{x|exception maybe: [[convert desert into pasture]]}}-->
* [[Mushrooms]] - a more efficient way to convert [[crop residues]] into protein
* [[Plant-based food]]