The roast beef of England has been consumed by the fire of spring; April has indeed proved the cruellest month. My local butcher, an excellent man but of a dying breed, tells me that he is having a very bad time. People don't seem to catch foot-and mouth-disease (there has been just one, somewhat equivocal case - but they said that about BSE, didn't they?), yet many now find themselves repelled by meat. Have the vegetarians been right all along? Should we consign carnivory to our barbarous past? Would it not be safer for each of us, individually, to become vegetarian? And good for the planet as a whole? Was BSE the portent, and FMD the coup de grace?
It is a close-run thing, but on balance the answer is no. Animal husbandry all over the world, when done well, is good and necessary. The arguments for vegetarianism don't quite work.
But they are certainly salutary. Modern livestock production really must mend its ways, for the epidemics are indeed an outrage. And while vegetarians are not quite equipped to take over the world, they do form a stout opposition. If farming is Greek tragedy (and the resemblance grows month by month with the hubris), then the veggies are the necessary Furies.
In terms of nutrition, vegetarians have won most of the battles, though they have lost some along the way: when Percy Bysshe Shelley gave up meat, he became even more languid than usual, until his unlikely friend Thomas Love Peacock recommended "three mutton chops with pepper". For most of the 20th century, protein seemed the main issue. Nutritionists in John Steinbeck's Tortilla Flat, written in 1935, wondered how a local Mexican boy flourished on an apparently exclusive diet of tortillas and frijoles. Their theory told them that neither maize (cereal) nor beans (pulses) contain enough protein to keep a gnat on its trembling feet, yet this presumptuous lad seemed bright as a button. Clearly, they concluded, he must be some kind of changeling. A freak of nature. It never occurred to them, as good scientists, to question their own theory.
But Steinbeck was a biologist manque and his anecdote was rooted in contemporary thinking. Notably, in the early 1930s, Cicely Williams suggested after preliminary studies in Africa that kwashiorkor, the strange pot-bellied syndrome that afflicts many children suffering malnutrition, resulted not from a lack of food in general, but specifically from a deficiency of protein. In the middle decades of the 20th century, this became the dogma (even though some brave souls were questioning it by the early 1950s).
Protein seemed to mean meat, eggs, milk, and then more of the same, which suited the newly invigorated, newly bullish agriculture of postwar Britain and the US: meat removes the ceiling on turnover, and is the key to riches. Commerce, nutritional theory and hedonism (because people like meat) marched precisely in step, which is rarely the case. Meat was marketed as keenly as Craven A cigarettes and nylons, and yet had virtue on its side. A fine American academic, Georg Borgstrom, wrote a book in the 1960s to prove that most of humanity must already be dead, since they were clearly protein-deficient.
The tide truly turned in the 1970s, on three fronts. First, protein ceased to be the elixir. The concept of "protein-sparing" came to the fore. Williams was right: the kwashiorkor children were protein-deficient. But that was not because their diet lacked protein. It lacked energy, and their desperate bodies, needing to survive second by second, "burned" precious protein to supply it.
Energy could be supplied much more cheaply, and for the body more easily, by carbohydrate - starch or fat. This would then "spare" the protein. Nutritionists now vied with each other to reduce the recommended daily dose. Suddenly, and with wondrous serendipity, all the great staples emerged as adequate sources of protein: pulses, cereals, even potatoes. People can live almost exclusively on potatoes. As a final bonus, pulse protein makes good any deficiency in cereal protein, so that frijoles and tortillas (or dhal and chapatti or beans on toast) make a perfect match.
This "paradigm shift" was perhaps the most significant revelation of the 20th century, because it implied, after all, that humanity could feed itself. But there was more, for nutritionists also began at last to accept that dietary fibre, hitherto disdained as "roughage", was in various ways auspicious, not to say vital - and fibre is supplied by plants. Finally, and most conspicuously, people grew worried by saturated fat, which is mainly the domain of animal flesh, and enthused by unsaturates - for example, from sunflowers (polyunsaturated) and olives (monounsaturated).
Nutritionally, however, animal food still has much to offer - particularly for poorer people, or in far-flung places, without access to vegetables of excellent quality or to a health-food shop. Some minerals, notably zinc and calcium, are hard to guarantee without animal products. Parts of animals also supply recondite "essential fats", which perhaps are of particular importance for the development of nerves and brains. In many countries - in semi-deserts and high latitudes - it is far easier to produce livestock than to grow reliable crops; so animals become prime sources of both protein and energy. In all countries, animal products are good nutritional underwriters - good guarantors of quality. Peacock's instincts were spot on.
"Animal products" should be defined broadly, however: to include the trotters and offal that were once part of every traditional cuisine. The supermarkets' dedication to steaks and cutlets, profitable though this may be, is nutritionally pernicious. And animal products should not be eaten in vast amounts. Great cuisines use meat as garnish; it becomes the centrepiece only on feast days. Excess is vulgar, to say the least, as any vegetarian would attest. Still, a low-meat diet is better than a no-meat diet.
It is not true - or not as true as they would like it to be - that vegetarians have no blood on their hands. It is true that modern ways of producing livestock are often disgusting. Common sense says that the battery and the intensive-care unit are cruel, and such science as there is (it is hard to fund appropriate studies) supports common sense. The insouciance is increasing, too: there are "pig cities" in the US with a million desperate creatures on board. Genetic engineering is not innately evil, when tempered by aesthetics and good sense; but when applied to animals in the cause of productivity, it has proved vile - enough to give all science a bad name, as many scientists themselves point out.
But the human species cannot survive without farming, except in trivial numbers; and we cannot survive at all without encroaching on animals to some extent. Even the vegans must clear the jungle to grow their cabbages and corn. Every human being who elects to live causes at least some animals to die. Simple morality suggests - at least to a lot of people, including me - that the carnage and the suffering that we cause to animals should be minimal, and never gratuitous. I despise fox-hunting, for instance, although that is another story. Vegetarians cannot avoid the blood on their hands, but do they have less blood than the rest of us? Do they have the least that is possible?
Here, there is a dichotomy: between the vegans who eschew all animal products that directly involve the death of animals, including leather, and the varying shades of "lacto-ovo" vegetarians who accept milk and eggs and sometimes fish (among which, as in Japan, they sometimes classify whales). The vegans have purity on their side, and do seem to occupy high moral ground. The lacto-ovo case seems merely effete.
Lacto-vegetarians rely heavily on dairy products (which means, incidentally, that many of their most highly prized recipes are high in the dreaded saturated fat). Cows cannot lactate unless they first produce a calf, and this raises a host of practical and moral issues. Dairy cows produce one calf a year after a nine-month pregnancy. The calves are then taken away, and the cows milked for the following ten months. Thus, at any time, they are either lactating or they are heavily pregnant; for seven months of the year, they are both. Typically, in modern systems, they produce their first calf when two years old (first becoming pregnant at about 15 months), and the average age at slaughter, when they typically go for pies, is now around five years. They produce around 1,000 gallons in the ten-month lactation, although the 2,000-gallon cow is not uncommon. Not surprisingly, those with the biggest udders are prone to lameness. Wild, ancestral cows, by contrast, produce about 300 gallons a year, and may live until they are about 15. In the wild, too, cattle live in herds of about a dozen, with a recognised social hierarchy. The average modern British herd has about 100 animals - a constant crowd.
Thus the life of dairy cows is short (by cattle standards) and hard. It is becoming possible to bias the sex ratio of their calves as required, but only a few females are kept as herd replacements and the rest are killed. So are all the males. We could put the superannuated cows and their calves into retirement homes, like donkey sanctuaries. But in a few years we would need a sanctuary the size of Europe to accommodate the surplus animals from Britain's dairy herd alone, and soon after that they would occupy the whole world. Death must be built in to the system. The question is not whether but when the calves should be slaughtered.
They can be kept for veal - which need not be the obscene practice it has sometimes been, if we do not insist on anaemic meat. Or, if the cow has been crossed with a beefy bull, the calves can be raised for 18 months or so and killed for beef. Most of Britain's beef comes from this source. A cow requires a huge intake of energy and hence of food to produce a calf. If the calf is simply thrown away, then the input is wasted, and such waste is surely a sin. Since slaughter is inevitable anyway, the only thrifty course is to eat the meat that results. In this, the lacto-vegetarians are on dubious moral ground indeed.
Vegetarians also argue that an all-plant diet makes better use of landscape and resource, and hence is better for the entire planet. After all, a field laid out to wheat or potatoes yields at least ten times as much protein and energy as one devoted to cattle or sheep. Indeed so; but some fields are too steep or cold or rocky or high or marshy or dry to yield crops at all, although they might support sheep or goats. All crop production produces surpluses and leftovers, and this is the traditional domain of pigs and poultry. In short, however many crops you may fit into a given stretch of land, you can always produce even more human food if you add a few animals. The mistake is to add too many: not to complement production of cereals and pulses with livestock, but to grow them specifically to feed to livestock, which is what we do on an ever-increasing scale in the west. But again, although we see that the no-meat diet is better than the high-meat diet that has become the norm in the past half-century, it is surpassed none the less by the low-meat diet.
Finally, on the matter of morality, we might turn to Immanuel Kant, as doughty a court of appeal on such issues as ever there was. He suggested that no course of action can be morally unimpeachable unless it might be recommended, in principle, to everybody. Vegetarianism could not safely or responsibly be recommended to all the world's people. We in the west, who eat most meat, could indeed do without it all together. But even we would benefit from eating just a little; and there are many places without fertile plains and a forgiving climate that would be lost without it.
So while vegetarians occupy a moral high ground, they do not occupy the highest ground conceivable. They make many sound points and should be listened to. In particular, they have possibly done more than anyone to counter the hysteria of the postwar decades, when medical science and agricultural economy combined to persuade humanity as a whole that we would surely die without meat, meat, and more meat: perhaps the most pernicious piece of nonsense, both individually and globally, as can be conceived. Vegetarians have shown, after all, that with a following wind we can do without meat altogether, which is good to know.
The trick and the challenge, none the less, is not to banish animals, but to keep them properly - in proper numbers, and with due attention to their inevitable parasites. The biology is straightforward. Economics is the problem. If we want to be kind, and safe, then we must pay. And because meat shouldn't just mean steak, we must relearn how to cook.
Colin Tudge's In Mendel's Footnotes is published by Jonathan Cape (£17.99)