Is it simply that politically it would be extremely controversial to raise taxes on meat? In Europe we have very high taxes on petrol and petrol is universally used. It could also be argued that its use is beneficial to economic productivity too, yet that seems to be accepted by most people. So why can't we do the same for meat?
Say 10% of the calories produced for me at a human go to waste. And I can convert them at 25% efficiency to usable calories via a chicken. Then I have just increased the yield of usable calories by 2.5%. In consequence, I need to buy less and thus emissions can be reduced.
And wheat can be converted to pasta, which can be stored for years, and can be easily made edible by brief cooking. You can reduce wastage of wheat to negligible levels, and chicken farming has non-zero overhead, so it seems unlikely that the chickens are an efficiency win if you take reasonable care.
You're not taking into account that, by virtue of being an animal taking in oxygen and creating carbon dioxide / other pollutants, the chicken itself is contributing to greenhouse gas emissions.
The question is, in real life, are the bonus calories we get from animal farming efficient enough so as to be worth those greenhouse gases? Given the massive GHG emissions of animal agriculture, it doesn't seem so.
Perhaps I'm misunderstanding your example, though: feedback appreciated
If you feed the goat 100 calories, there is no way you get back 100 calories.
It's always better plant and eat the food directly than to feed it to an animal.
Of course, if you're in a scenario where you live on a small island with no connection to the outside world, and you only have marginal land, yes, you need might need to have livestock to survive. But that's not what we're talking about here.
https://en.wikipedia.org/wiki/Ecological_efficiency#Ten_perc...
> When organisms are consumed, approximately 10% of the energy in the food is fixed into their flesh and is available for next trophic level (carnivores or omnivores). When a carnivore or an omnivore in turn consumes that animal, only about 10% of energy is fixed in its flesh for the higher level.