How can Humans Eat Grass?

Every summer I mark GCSE Biology examinations, and every year I end up really depressed when I mark the agriculture or food question.  In a nutshell, the average British 16 year old – if what they write in this national examination is to be believed – has learnt that livestock farming has nothing good to offer society.  According to the 1500 or so exams I have read in the last three years, the majority of British 16 year olds believe that

  • farmers rear animals indoors because they enjoy (or at best don’t care) making animals unhappy,
  • everyone, human and livestock, would be better off if we were all vegetarian because then food would not be wasted on animals:  humans could eat animal food and that would be much more efficient,
  • possibly best of all would be if we grew all our protein in large silos in the form of fungus (this is what makes Quorn) because it protects farmland and has a much higher protein content than meat.

As is so often the case, there are grains of truth in all these which have been grotesquely distorted.  Some may be put down to adolescent inattention or intellectual incapacity, but strikingly similar arguments crop up in batches and frequently, which implies that the teacher has at best a poor understanding of the topic and at worst an ‘agenda’.

Aberdeen Angus in the water meadow, Lleyn sheep on the hill

Aberdeen Angus in the water meadow, Lleyn sheep on the hill

This photograph would not be possible in a society where no one ate meat.  I have read exam scripts in which it appears young people are being encouraged to think that if no one ate meat then farm animals would be left to live to a ripe old age in bucolic bliss.  They are also being given the impression that all livestock are fed entirely on grains which could also feed humans.  This may be true of the great stockyards of the United States, but in this country a significant part of the nutrient intake of cows and sheep is grass.

Feeding livestock with grass is a way of using land which could not be used for anything else.  The water meadow could flood.  The hill in the background is rather steep.  So both would probably be unsuitable for arable crops.  And even arable fields periodically need a rest:  a grass ley provides this as part of a crop rotation.

There is a ‘grain’ of truth in the argument that feeding grain to livestock is not the most energy-efficient (in terms of calorific content) way of growing food.  Dairy cattle in particular need extra inputs to enable them to make the many litres of milk that they produce each day.  Maybe the best compromise would be to keep using these excellent converters of grass into human food, but moderate our meat and dairy product intake whilst doing a better job of consuming the ‘5 a day’ of fruit and veg!

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