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Comment by raws | Hacker News Reader

I'm highly dubious of the statement that growing plants to eat them is lightly less polluting than growing plants, feeding them to cattle and then preparing the cattle to eat the meat. Cattle does not sequester CO2 like plants do and emits greenhouse gases. Also uses way more treated water.

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When cattle are raised on well managed pasture, there is zero transportation between the cattle and feed, where as all vegetables requires transportation, and more of it pound-per-pound to reach the nutrient value of beef.

Cattle only contribute GHG when raised on grain as their digestive systems creates excessive methane breaking down corn. If more people understood how cows and ruminants should work vs how they are currently used in the industrialized feed complexes, they'd realize cows are not the problem, it's how we are using them.

There is a big difference is growing plants for human consumption when compared to growing feed for an animals and then consuming the animal meat.

Basic biology says that when cattle eat feed only of portion of that feed ends up as meat.

The farming industry actually measures this using a measure called the Feed Conversion Ratio.

https://en.wikipedia.org/wiki/Feed_conversion_ratio#Beef_cat...

For example the FCR for cattle is over 4 meaning for every unit of animal mass you'll need over 4 times that mass in feed.

This basic biology means it is always be more efficient to grow vegetables for direct consumption than to grow them for animal feed.

Right, but cattle can be raised where growing plants is impossible, and they can be fed by-products of plant agriculture that is not fit for human consumption.

It's really not an either-or, something that I feel is often lost in these discussions. Eating plants and meat is complementary, and has been for all of human history.

What percentage of cattle actually subsists on otherwise barren lands, and what percentage is fed soy and grains explicitly grown for them.

It's also becoming possible to grow plants hydroponically in a highly automated and controlled environment (warehouse/cattle shed), with up to a 98% saving in treated water usage, 60% less nutrients required but with more nutritious crops and no pesticides. This is the case for High Pressure Aeroponics, which is slightly more complex than other hydroponic methods.

https://spinoff.nasa.gov/Spinoff2008/ch_3.html

That's an interesting point, but isn't it also true that hydroponics are currently just not a very economically feasible option?

Depends on the crop. I know a lot of lettuce is grown Hydroponically. (but its basicly cellulose and water to begin with).

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