AN ACRE A MEAL? - MEAT: A Benign Extravagance - page 29

Also of interest to British observers is the productivity of our wide expanses of wheat
compared to that of dense forests of fodder maize. It looks as though the fodder maize pro-
duces more nutrients: and indeed it does, but only just, because a lot of that maize is water.
An average field of fodder maize in the UK provides 900 kg of protein and 130 gigajoules
of energy, while an average field of wheat produces 825 kg of protein and 108 gigajoules
of energy. Since a wheatfield also produces several tonnes of useful straw, it is clear that in
the UK feeding wheat to humans is far more efficient than feeding silage maize to cows. 30
We should also bear in mind that in the rainy South West you can easily get a high yield
from maize, but rather less easily from wheat; whereas in East Anglia bumper yields of
wheat are easily achievable, while fodder maize is less common. In other words the relative
productivity of animal feed crops and human food crops varies according to the locality.
Although the differences in yield, on aggregate, are marginal, they can sometimes be sig-
nificant, and I'm inclined to allow livestock farmers an advantage here, because they have
greater ability to adapt to the local situation. In some situations animal fodder grows more
abundantly than human food, and the carnivore farmer has a choice, whereas the vegan
farmer doesn't.
It is also apparent that the animal feeds which are more likely to outperform human food
crops are bulky whole-plant forages such as maize silage, brassicas, root crops, lucerne, or
even grass, and these are more accessible to cattle than either to pigs and poultry, which
do best on grain. As we have seen, cattle are also the animals which provide most in the
way of leather and other byproducts. Both these factors serve to lower the feed conversion
factor for beef in particular (at a guess to round about 7:1 or 8:1) and narrow the difference
in performance between cattle and the non-ruminant species.
The Global Pig Bucket
There is a further reason why higher yields are obtained from feedcrops: animals are
less fussy. Humans, unless they are underfed, tend to discard substandard seeds, roots
and fruits; animals, unless they are overfed, have much lower standards. Humans like to
mill grain, and milling reduces the yield of wheat by nine per cent - animals aren't so
bothered. 31 Of the 24 tonnes of potatoes that might be produced on a hectare, a proportion
might be substandard, a further proportion might go off in storage, and 22 per cent of the
remainder might be discarded as peel, 32 but a pig would eat the lot. The food rejected by
humans is often fed to animals, as bran, cake or in a compound feed, and this brings us
on to the matter which threatens to make a complete nonsense of all these feed conversion
ratios: that animals eat things which humans don't eat.
Human-inedible biomass can be loosely divided into two kinds: the stuff that we can't
eat and the stuff that we won't eat. The vegetable matter we can't eat consists mainly of