Grass Finishing and Rotational Grazing: Why It's Both Essential and Not Enough
Our farming philosophy has always been to raise no more meat than is necessary to preserve and enhance the ecology, e.g. building soil, trapping carbon, and nourishing people, all at the same time. Our stance is that the world - and the United States in particular - produces far and away more livestock than necessary for this purpose.
Key points we make for the argument that people need to eat far less meat:
1.) Agriculture only contributes ~10% of total greenhouse gas emissions. GHG is not the environmental onion for agriculture.
2.) The two major environmental items regarding meat - cattle in particular - are a.) water use, and b.) land use, both of which are extractive and unsustainable
As can be surmized from the image on the left, a gigantic portion of the U.S. landmass is devoted devote to cattle pasture and livestock feed. And a careful look at the rest of the map will demonstrate that there's very little land left for livestock agriculture to expand into without environmentally deleterious consequences.
Perhaps a little scarier is the issue of water use. Half the grains grown in the United States are devoted to animal feeds, and most of those grains are grown in the U.S. corn belt. The problem is, the productivity of the grain belt is underwritten by groundwater irrigation from aquifers, many of which are non-renewable. Cattle are being fattened by grain grown with water that is effectively being mined.
Even as U.S. cattle becomes more efficient throughout the supply chain - higher feed grain yields, improved cattle and plant genetics, etc. - the industry still must contend with the fact that efficiency gains at the margins are coinciding with a global increase in demand that far outpaces those advances. The call from the mainstream CAFO beef industry to "grow smarter meat, not less meat" is essentially a call to preserve an incumbent industry by managing environmental decline.
What About Rotational Grazing and Grass-Fed Beef?
Rotational grazing can drastically reduce the amount of land required to raise beef, while improving forage quantity, soil health, and water use at the same time. There is a common argument from the CAFO beef industry that grass-fed beef actually consumes more resources - particularly water - because it spends as much as an additional year on the hoof. But that argument only holds water (ha) if you're only considering the water the animal actually drinks, and not the water required to grow the animal's feed.
It takes 2,500 gallons of water to produce a bushel of corn*, and about 80 bushels of corn to bring a finishing beef to slaughter weight, leading to 200,000 gallons of water to finish the animal (plus about 5,400 gallons of drinking water over 180 days, assuming a very high rate of 30 gallons per day).
In the grass-fed model, the animal consumes only the water it drinks. We'll assume our grass finished steer is drinking 30 gallons of water per day for the 180 days it would have spent in the feedlot, plus the 365 extra days required for grass finishing. (180 + 365) x 30 = 16,350 gallons.
So even under the best water management for its feed grains, grain finishing requires more than 12 times as much water for the finishing process as grass finishing. Under conventional water management, it's closer to 20.
Land use is a less straightforward issue. Of the 95 million head of cattle in the U.S., about 15 million are on feed (in feedlots). Taking that 15 million out of the lots and back on pasture would require an additional 15 million x (365+180) cow days of grass = 8.175 billion cow days of grass.** This is not a figure that translates readily to acreage, because the amount of space a cow needs depends on the amount of forage available. A steer could graze on a single acre in Virginia where it might need 30 in Texas. So let's assume generously that we're going to ship all that CAFO beef to the lush and well-watered grass of the eastern seaboard, and assume even more generously that all of the grass is the 100 cow day per acre feast waiting for the cattle at Polyface. Then it's simple division: 8,175,000,000 cow days / 100 cow days/acre = 81,750,000 acres.
That's a hair more than the combined acreage of Virginia, Pennsylvania, Maryland, and West Virginia.
There is an argument to be made that this land mass COULD come from the reduced land use devoted to animal feeds, and to more land being available from the remaining 80 million head of cattle being moved to a rotational grazing system. But you have to remember that a.) the land taken out of grain growth in the corn belt can't support the stocking rates we have here in the east, and b.) most cattle are grazed on marginal or semi-marginal land west of the Mississippi River, where efficiency gains from MIRG aren't going to be as pronounced as they are here in the east.
The Solution, Then?
My unrefined three-part solution:
1.) Return the size of beef herds to roughly that of the bison herds that created the deep, rich soils currently being mined in the corn belt, which is estimated at around 30 million head. They must be rotationally grazed with the purpose of restoring tallgrass prairie as both a carbon sink and a source of biodiversity.
2.) Cropland vacated by cattle - and then restored by cattle - should be returned to production of human edible plants, ideally focused on perennials, which are far less resource intensive to produce than cattle.
3.) IF the amount of beef produced in this system puts it out of economic range for too many people (this is likely), and/or does not produce the amount of meat in line with nutritional recommendations (this seems extremely unlikely), then cultured meats and systemic, managed game harvesting should be pursued as a environmentally and economically cost-effective means to make up the shortfall
Questions or comments? Leave them here or email the author at firstname.lastname@example.org
*2,500 is the most conservative estimate I've seen. Most are between 3-4K gal/bu.
**A "cow day" is roughly the amount of grass an adult steer or cow will eat in a day