WHY FEED LIVESTOCK ON GRASS AND BROWSE? (And why feed ruminants on anything else?)

Environmentalists have long been telling us that too much livestock is a bad thing. Nutritionists have blamed saturated animal fats for human heart disease and various cancers. Many people, for various reasons, seem to believe that we should keep no livestock at all.

Of late, the gainsayers have been making common cause with industrialists and politicians – not to attack livestock in general, but to condemn grass and browse in particular.  For both factions tell us from their different points of view that conversion of grass and browse into meat and milk is grossly “inefficient”. Worse, they say: cattle raised on grass produces more methane per lifetime than cattle raised largely on a more concentrated diet of grain and soya, and methane is among the most potent of the common GHGs (greenhouse gases). To be sure, methane is far less stable than carbon dioxide, and rapidly oxidizes in the atmosphere (to form carbon dioxide) – but nonetheless, it is believed to be significant.

But the pastoralists have been fighting back. As they have been pointing out for decades (and was obvious to our ancient forebears) grass and browse can flourish in places where cultivated crops cannot — so in agricultural terms at least, grazing on pasture (particularly wild pasture) is all gain. More recently, Graham Harvey argues in The Carbon Fields that beef and milk produced from good pastureland do not contain harmful amounts of saturated fats – and in fact provide beneficial polyunsaturates in just the kind of ratios that human beings need. He also points out that well-managed pastureland is a net carbon sink – sequestering more carbon than the cattle exhale as methane.

A great deal rests on all this. The number of livestock and the way in which we feed them largely determine the structure of all of agriculture in each and every country. Animals are a major component of human diet and of all economies. Huge numbers of people earn their living from them. Their presence or absence determines the form of the landscape, and the fate of other creatures that might be living there – creatures that might co-exist with the grazing livestock, or be pushed aside by them.

In fact, if we get livestock right, then humanity, and a far larger proportion of our fellow creatures, have a good chance of pulling through the next few difficult decades; and there is good reason to think (as discussed elsewhere) that if we get through the next few decades in a tolerable state, we could be set fair for the next million years. But if we get livestock wrong, then we are in even deeper trouble than is obvious; and at the moment, we are getting livestock horribly wrong.

The issue grows knottier and knottier, as Alice might have said, the more you look at it. It all needs input from the best informed experts – farmers, scientists, economists. We hope that this section will provide the necessary forum. The aim – as throughout this entire website – is to get to the truth, to lay out the facts and the philosophy for all the world to see – replace the rhetoric and speculation that now prevails in the world at large with a little scholarship, of the kind that seems to have gone missing; and to pinpoint the problems that now, so obviously, need research.

My own self-appointed and decidedly non-expert role in all this is simply to outline the general shape of the argument as it seems to me – and, much more to the point, to  invite others to get stuck in. So:

The rest of this section could/ should operate as a WIKI: anyone who has good information to impart would be able to add their ha’porth to the general pool. By this means we should rapidly create a dossier that is truly worthwhile – a summary of what’s known, and a sense of what is unknown, and potentially important, and needs to be further investigated.  This dossier, with a little tidying up, should rapidly become a testament with which to confront government, industry, academe, and the world. Heaven forfend that I should attempt to anticipate the course of the discussion, but I confess I hope and trust that it will show, beyond all reasonable doubt, that feeding on natural pasture and browse is indeed highly desirable, and that more “intensive” systems are far less so – and that we need to change direction, back to something more biologically based, asap.

To help things along (I hope) I have divided the hoped-for discussion into topics, as follows. Please add and alter as you see fit!



The figures on the first few issues seem fairly well known and standard. But it would be very good to present all this basic data in easily visible and manipulable form. Does anyone know if and where this has been done already?

For starters, we need to establish:

** How many livestock are there in the world?

— in each place?

How many specialist herbivores

— including ruminants (which mainly means cattle and deer)

— and non ruminants (horses, rabbits, etc)

— (plus pigs and poultry which can also derive significant nutrition from grass and browse)

How many of each kind?

— and among cattle: how many European style animals; how many zebu; how many water buffalo; how many bison

** How much feed do all these animals need?

** Worldwide, as things are, how much do they get from grass and browse

— and how much from cereals etc?

** In different societies, cattle in particular serve many functions – and often milk and meat are subsidiary. So we should also be asking – what is the actual role of cattle in different societies? (Gung-ho replacement of traditional cattle and systems with European-style intensive units in the name of “progress” is truly bull-in-china-shop: profitable (for the perpetrators) but often (usually) hugely destructive).


The immediate focus, however, is cattle for meat and milk. For both, there are many systems worldwide. We can identify spectra: intensive-extensive; temperate-tropical; traditional-industrial; intensive grazing, zero-grazing, feedlots; and so on and so on.

Within this there are crucial details such as: organic vs “conventional” (meaning industrial); natural pasture vs “improved” pasture (with various degrees of improvement); and so on.

Then there are what to many might seem like peripheral details but are of crucial importance within their own societies such as: cattle as garbage disposal units in traditional India; cattle as consumers of crop residues including pigeon pea sticks in traditional India; and so on.

Following from this we have cattle worldwide as part of integrated systems – from western rotations to the kinds of systems seen in SE Asia involving rice, horticulture, ducks, pigs, and water buffalo; and worldwide as cattle are fed on browse.

Crucial too, worldwide, are the niceties of pasture. What kinds of grasses? What proportion of legumes? Which ones? What proportion of wild herbs (eg, we know a farmer in Cornwall who speaks very highly of the otherwise dreaded Japanese knotweed. We will try to persuade him to write for us).

All this needs laying out and talking through. As a local (Oxfordshire) farming friend is wont to comment, “In farming, the Devil lies in the detail”.


We need to know exactly what is out there including

— the extent of the land

— the quality of the land

— how usable it is (altitude, water – too much or too little, etc)

— how much feed it can provide

— how much feed it can provide while still supporting a local flora and fauna


This is crucial. “Grass fed” could mean wild vegetation (which in truth may contain very little grass at all); or it could mean intensive, heavily fertilized custom-bred ryegrass. The economics and biology of intensive ryegrass may be closer to the cereal feeding than it to wild pasture.

We need definitions.


This is clearly key. The basic biology, as Graham Harvey describes it, is that the mycorrhyzal fungi that wild pasture depends upon, convert atmospheric carbon into organic forms that happen (for what reason?) to decay rather slowly. If the grass is grazed judiciously, leaving some of the roots (and their mycorrhyzae) to die off at intervals, these organic compounds build up in the soil, sequestering the carbon and improving soil texture.

There is hard research on this but it is so important in principle that there surely should be more. We have to know in detail how this works (the mechanisms) and how and under what circumstances it works best. What kind of plants? What kind of soil? What kind of climate? What kind of grazing regime?


It’s amazing how few people seem to grasp the biological basics – even among farmers (let alone policy-makers). Specialist herbivores in general are animals that have mastered the arts of deriving energy from cellulose. Cellulose is a carbohydrate and is the chief (though by no means the only) component of plant cell walls. As such is it one of the commonest organic molecules in nature and for those that can make use of it, it is a cornucopia. But there are a couple of snags. First, to all animals (the reported exceptions generally turn out to be mistaken) cellulose is indigestible. So those that rely on it must make use of microbes – bacteria, archaeans, and protozoa – that live in vast fermenting chambers that form part of their gut.

Secondly, in leaves and stems, as in grass, the plant cell walls surround cells that are full of water, so stems and leaves are very bulky relative to their energy and protein content. So specialist grazers and browsers must be bulk feeders. Put both these facts together and we find that specialist grazers and browsers, at least among birds and mammals, are always big: nothing smaller than a grouse or a rabbit. In animals much smaller than this, the metabolic rate is too high to be maintained on a low-energy diet; and they just aren’t able to eat enough (or carry a fermenting chamber big enough to provide them with all the energy they need). So any mammal smaller than a rabbit or any bird smaller than a grouse that contrives to live on a diet of plants must feed on seeds. Seeds are designed by nature to nourish the plant’s own embryos, and are packed with nourishment (starch, oil, protein) with very little water. Hence mice and goldfinches.

Specialist grazers and browsers are either “foregut digesters” or “hindgut digesters”. The foregut digesters have stomachs modified as fermenting chambers, while the hindgut digesters have enlarged colons or caecums (diversions of the gut) or both to do the same job. The principal foregut digesters are the ruminants – and they are the ones that concern us most, because they include cattle and sheep (and goats and deer). They have complex stomachs which include a huge fermenting chamber known as the rumen.

But there are other, non-ruminant foregut digesters too. Camels, llamas, etc are commonly loosely classed as “pseudo-ruminants” (they are fairly close relatives of ruminants, but may have arrived at their foregut digestion independently). Both ruminants and camelids regurgitate their food from the rumen to give it a second chew (and the second time round it by-passes the rumen and carries on down the gut). Kangaroos are also foregut digesters although of course they are quite unrelated to ruminants, while the only foregut digesters known among birds is the hoatzin, a most peculiar creature from Amazonia.

All other specialist grazers and browsers are hindgut digesters, including horses and rhinos, rabbits, elephants, koalas, ostriches, grouse, and so on. The extent to which omnivores such as pigs can derive energy from cellulose by hindgut fermentation seems to be controversial . Some breeds, such as the Berkshire, are widely recognized as grass feeders, though some say that other breeds are perfectly capable of adapting (It would be very good to throw more light on this!).

Ruminants are recognisable in the fossil record not from their guts (which are very rarely fossilized) but from their teeth: ruminants in general have lost the upper incisors. The fossils tell us that they first appeared in the North America and Eurasia by the Upper Eocene (about 35 million years ago) and in Africa in the Early Miocene (around 20 million years ago). There is an honourable history ever since of both grazing and browsing ruminants. But after the Eocene the world grew steadily cooler and drier and forest more and more gave way to grassland – which from the Miocene onwards were very extensive indeed. So the grazing ruminants, extreme specialists, became the commonest large animals on Earth, by far, and among the most various. There must have been vast herds everywhere, of cattle, antelope, deer, and relatives of the modern pronghorn. But the biggest herbivores of all in any age were always hind-gut digesters, like elephants and rhinos (and others long since extinct). Hind gut digesters are especially good at coping with very low-grade fodder because they push the food through more quickly and don’t waste time, as ruminants do, extracting every last calorie. But this tactic works best in very big animals with a very low metabolic rate. (The biggest living ruminants are the giraffes – not grazers but browsers).

Cellulose is compounded from molecules of glucose joined end to end, so you might suppose that the microbes that so obligingly break it up in the herbivores’ guts break it into glucose, and that from then on the metabolism would proceed as it does in humans. But not so. The cellulose is broken down into “volatile fatty acids”, VFAs, which for cattle and sheep are the chief source of energy. All their nutritional physiology is geared to this.

Cattle in the wild surely eat some seeds, but cattle fed exclusively on “concentrate” (seeds in the form of cereal, oilseeds, and legumes, which nowadays means soya) are definitely playing away from home. This is not what their metabolism is intended to cope with at all. Such fare is for mice. Metabolic disorders of various kinds are only to be expected, and indeed are a hazard. But if the cattle don’t get sick on cereal then they grow fast, and fatten early, and since oil is still cheap and is the ultimate source of fertilizer, pesticide, and herbicide, cereal is also cheap. So as things are it can be highly profitable to raise cattle in particular largely or exclusively on concentrate. It increases turnover no end if the animals grow quickly.

Some research suggests (and indeed it seems pretty clear) that although cattle are built for a low-grade, bulky diet (leaves) rather than a concentrated, seedy diet, they actually convert more of the latter into milk and meat than of the former. In both cases, some of the carbon in their feed is converted into methane, which escapes into the atmosphere; but they produce more methane when fed on grass and browse, than on concentrate.

But the diet also affects the quality of the meat and milk. As Graham Harvey outlines in The Carbon Fields, animals raised quickly on concentrate have a higher ratio of saturated fats in their milk and meat, and a lower proportion of the polyunsaturated fats that nutritionists call “essential”. So on the face of things at least it seems that grass-fed beef and milk are better for us than concentrate-fed beef and milk. Indeed, it could be that grass fed meat and milk and positively good for us, while cereal-fed beef and milk, eaten in more than modest quantities, are bad for us.

But all of this of course needs further research and adumbration – but, as so often with issues that really matter, the necessary research is not being done with the intensity that seems necessary. It is convenient, for commercial purposes, to assume that we already know all we need to know – that cattle grow quicker when fed on concentrate, and so long as oil is cheap that must be the right thing to do. This is the level of banality we find in high places these days, which people who give a damn have to battle against.

So the issues for discussion are:

** The further details of herbivore nutrition, including the intricacies of rumination.

** Why do ruminants (and all animals that eat plants) produce methane?

** How much more methane do they produce on browse and grass than when fed on cereals?

And so on.

All this leads us to:


** Metabolic disorders. Given that ruminants have been adapting for so long to a cellulose-based bulk diet, we might expect them to suffer metabolically when given a diet of concentrates. It is a grave physiological insult. So it transpires. More needs to be known.

** Infection. However, animals that do not venture to the fields, whether fed on grass brought in or on concentrate, should presumably suffer less from grass-born diseases such as worms, or wildlife-borne infections such as TB.

On the other hand, the ghastly episode of BSE could not and did not occur among animals fed outside on a natural diet. It resulted entirely from a particularly cynical form of intensive feeding.

** Micronutrients. Micronutrients and what might be called “tonics” (what the pharmaceutical industry now calls “nutraceuticals”) clearly play a far larger part in animal, including human, health than formerly appreciated. This is entirely to be expected on evolutionary grounds: all animals have been adapting to whatever is around since animals first appeared on this Earth, and we would expect a very great deal of symbiosis. We would also expect that many of the beneficial effects of recondite natural ingredients would be very hard to detect – which is why the science of “nutraceuticals” is still so new (and, such is the way of the modern world, has already largely been pre-empted by the pharmaceutical industry). Anecdotally, there is a great deal of evidence that animals on a natural diet fare far better than those fed artificially since, even with the best will in the world, no-one knows in great enough detail what animals really benefit from. Among those anecdotes is Ben Mead’s – that his vet bill in 2008 for 400 dairy cattle fed on wild vegetation was £13.00, and that was for an injury caused by barbed wire. These anecdotes need to be taken very seriously – and turned into something solid. Meanwhile I have written in speculative vein about the reasons why such micro-nutrients are important in “Pharmacological Impoverishment” (which will be posted on this website when we can get round to it and meanwhile can be read on www.colintudge.com)


We need to pin down the evidence which says that the chemistry of body fat is different in cattle raised on pasture rather than concentrate – and that this matters to human consumers.

Anyway, I won’t go on in such detail. I think the gist is clear enough. So this is the rest as I see it in note form:


Environmental issues include:

— the carbon story

— other inputs (notably water)

— effects of different systems on wildlife as a whole.

In outline the questions are:


** Is pasture really a net carbon sink?

— for how long

** How does this carbon sink work?

— microbiology

— evidence !

** How much carbon is used in inputs

— to fertilize cereals

— to fertilize grass (if any!)

— to plough fields

— for pesticides/ herbicides

And (as always)

— the special significance/ contribution of organic systems


** How much water the various systems need?

— irrigation !!


Impact of the various systems on wild ecosystems!

— v complex


** How do the different systems impact on people’s lives

** How many people do they involve

** Food culture!

— traditional cuisines are low meat cuisines !!


** Vegans argue that the world could feed more people if there were no livestock.

If livestock kept as they are now

— this is correct

But if kept properly

— herbivores on grass and browse

— omnivores on leftovers and surpluses

Then livestock clearly increase overall efficiency!

** Efficiency = output divided by inputs

But what are the various inputs

— and how are they/ should they be measured!

Tricky one ! (Soon there should be an essay by Simon Fairley on the whole concept of efficiency. Like many other highly significant concepts in agriculture, it seems to have been very sloppily handled, and clearly means very different things in different contexts depending on who is arguing what).


** The details may differ from field to field

— but the principles are universal

— and are those of biology

— physiology; ecology (inc soil microbiology); botany; evolutionary theory (without which “nothing in biology makes sense”)

The industrial stuff

— is an exercise in industrial chemistry

— which the ill-informed equate with progressive science !!

** You would expect human food preferences

— to be geared to good nutrition

— and to good husbandry

— on evolutionary grounds!

** And the thesis of pharmacological impoverishment

— is rooted in evolutionary theory !

** No global warming in the Miocene

— when grasslands and herbivores probably most extensive!!

** Proper management of grazing and browse is also, of course, very much in the spirit of The Age of Biology!

Orchestration of whole ecosystems, with finesse and understanding

— as opposed to their wholesale replacement with brutalist industrial chemistry !!


** How the money stacks up

** Is the economic status quo

— ie the market

— fit for purpose?

** Economic/ political reasons behind rise in meat consumption

— meat has become an exercise in value-adding

— and to solve the problem of market elacsticity!

— ie it is too easy to feed people without excessive livestock!

— it’s a way of creating a problem

— to which is found a commercial solution!

** Why isn’t proper, government-sponsored research done into matters of universal importance, such as those raised here?

— must science be the handmaiden of big business?

— must government be the handmaiden of big business?

** Science must be rescued !!


** Often in agriculture (as in all walks of life) we see grand and necessary ideas corrupted by short-term expediency and commerce. Thus the “organic” label is sometimes used to conceal dubious practice (including transport of perishable goods half across the world), and “local” can mean local-but-not-very-good, and “free-range” can mean a glimpse of grass on alternate Thursdays, and so on. Similarly, we need to define grass-fed and pasture-fed very carefully. In particular, we need to differentiate between maximum-yield custom-bred monocultural ryegrass, and natural or only slightly improved wild pasture (which sometimes may contain very little grass at all. I know at least one farmer whose cattle are reared largely on sedges and other waterside plants).

Criteria have been drawn up, and we will publish them on this website as soon as we have the author’s permission to do so.


The British Grass-fed Livestock movement

The Crofters



We have an ever-growing list of people in various continents who are working with grass-fed or browse-fed livestock in various ways. We would love to publish details of them all and will do so when we have their permission.

That’s me done for the time being. Please contribute !!

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