Sustainable Livestock Feeding and Management: What Changes are Needed?

Introduction

The greater availability of accurate information about products and production systems of various kinds is increasingly changing many aspects of the world economy from a ‘push economy’ to a ‘pull economy’. While producers of food and other goods purchased by consumers formerly determined methods of production, consumers are now exerting more control on production methods (Broom 2014, 2017a). 40-50 years ago, many consumers stopped buying some goods on moral grounds, for example, carpets whose production involved child labour were ostracised. The World Trade Organization (WTO) permitted countries to ban imports of such goods on public morality grounds. At this time, and until about 20 years ago, the public wanted food products but farmers determined production methods. Then many retail companies such as supermarkets and fast-food chains were forced by consumers to sell Fair Trade and Welfare-Friendly products (Bennett et al 2002, Broom 2010). The demand pull by consumers has become more detailed as information has become more available (Kim and Lee, 2009, Antonelli and Gehringer, 2015). Retail food companies were also pressurised to publicly state their standards in a number of areas by consumers who said that they would refuse to buy anything from the companies if they continued to sell, for example, pig meat if sows were confined in stalls or tethers, or eggs from hens kept in battery cages. The WTO extended the use of the public morality reason for blocking imports, to include seal skins when the killing method was often not humane, and many governments changed legislation about livestock production (Broom 2016, 2017a).

The concepts of ‘one biology’, ‘one health’ and ‘one welfare’ emphasize the great similarities between humans and other animal species and are changing human attitudes (Tarazona et al 2020). Most people regulate their actions because they consider that each person has obligations to avoid causing harms to humans, other animals and aspects of the world environment. As a consequence, a key question about any system is whether or not it is sustainable (Aland and Madec 2009). Sustainability is now a broader concept than it was when first used (Herrero et al 2010). A system or procedure is sustainable if it is acceptable now and if its expected future effects are acceptable, in particular in relation to resource availability, consequences of functioning and morality of action (Broom 2014, modified after Broom 2001). Sustainability is demanded in relation to: travel, erecting buildings, heating or cooling buildings, producing clothes and all other goods, disposal of waste, etc. Examples given here are mainly from food production.

The quality of food, as assessed by many consumers now, is not just about taste and nutritional value but also includes its impacts on consumer health and various aspects of any perceived negative effects of its production. Moral issues concerning food production emphasise the close links between sustainability and food quality. A palatable, nutritious food item whose production method is unacceptable to the general public for any reason is not regarded as being of good quality and the production system is not sustainable. Some consumers would not purchase certain items whatever the price whilst others might buy them if the price was low so the market size was reduced. The rejection of food items produced in certain ways now varies less from country to country than was formerly the case.

Sustainability components

Sustainability has many components such as: adverse effects on human welfare, including human health, no fair reward for producers in poor countries, and not preserving rural communities; poor welfare of animals used in production; unacceptable genetic modification; harmful environmental effects such as causing climate change or biodiversity reduction; and inefficient use of world resources. In order to evaluate systems of production and products, the source of all raw materials and product modifiers and the fate and impact of all of the product after sale or usage must be taken into account. The life-cycle approach (Day et al 1981) requires evaluation of all environmental changes resulting from the system (Ciambrone 1997). Another terminology used is to say that all externalities of the functioning of the system must be measured, e.g those of motor vehicle use (Delucchi 2000) or of farming systems (Balmford et al 2012, 2018). There have been attempts to express all of the changes in terms of money, or carbon usage, or energy usage but none of these can be used for all sustainability components. The scoring method (Broom 2021a) must be based on scientific information. In order to be able to compare systems, in the example shown here, a score of any negative effects is allocated ranging from 0, for no negative effect, to -5 for the worst effect described in the scientific literature to occur. The scoring could also be positive. Where there is evidence that some consumers completely avoid a product because of the negativity of the particular component, this is indicated by Z.

How do we measure each component of sustainability that affects a system? Some impacts of food products on the human health component are positive. For ingestion of meat, saturated fats may increase the risk of disorders so consumer mortality or morbidity rate can be measured. Public opinion surveys may also provide quantitative information. Fair trade labels require good traceability of products for the main measure of the extent of the effect is what consumers buy. Job satisfaction on farms can be measured by asking people doing the work and considering ease of getting staff. Impacts on rural populations can be measured by human population movement and, to some extent, by use of questionnaires.

The welfare of production animals is an important sustainability component for livestock products. In Brazil, consumers stated that for beef, the welfare of the production animal is the most important sustainability attribute and that traceability is important (Burnier et al 2021). There is now much good quality scientific evidence about the welfare of production animals. Wild animal welfare and mortality rates are also affected by plant production but there is less scientific evidence about this.

Some genetic modification, including gene editing, can negatively change animal functioning in substantial ways. A range of genetic modification effects can be measured, as can public acceptances of GM products.

Environmental effects of livestock production systems can be measured by: greenhouse gas output, biodiversity reduction and pollution of water etc. per unit of product. Inefficient usage of world food resources is likely to become much more important as a factor affecting plant and animal production. One aspect is the amount of food waste produced and what happens to it. Another major factor is the energy loss between plant product and human consumption. Animals that eat leaves and other food that humans cannot eat, such as ruminants and herbivorous fish, will become more important than animals that are carnivores or that eat grain.

When wheat, maize, soya etc. are produced, it is much more efficient for humans to eat it rather than to feed it to pigs or poultry. Even worse is to feed it to ruminants as they can eat food that we cannot eat. If dairy cows are fed grain, food resources are wasted. The dairy production has a negative overall energy balance if more than 30% of cow diet is grain. Ruminants, herbivorous fish and insects are expected to be important sources of human food for the future. When the sustainability component land area per unit of meat is to be measured, the land needed to grow all food given to the animals must be measured, as well as land actually occupied by the animals (Broom 2019). The other ways in which the land could be used is relevant to the efficiency of use of world resources mentioned above. Similarly, the largest water cost is often that used in growing feed. Conserved water is usually a better measure of water cost than total water, including rainfall, while purified water has costs additional to the water costs themselves.

Beef sustainability

What do we know about the sustainability of beef production systems? Recent and current world production of beef has high greenhouse gas production (Steinfeld 2006). Extensive beef uses a lot of land so there is less land available for conservation but more highly productive beef systems have environmental advantages over low production systems Balmford et al 2012, Balmford 2021). There have been improvements in water usage, land usage and greenhousegas production as compared with 40 years ago (Capper 2011). However, there are large differences across current beef production systems in the amount of land and water needed per kilo of beef (Broom 2019). Beef and lamb can be produced using plant material that humans cannot eat. It would therefore be better to stop feeding substantial amounts of grain to ruminants (Eisler et al 2014, Wilkinson and Lee 2017). Given this background, an analysis of the following widely-used beef production systems was carried out: extensive pasture degraded or not degraded; fertilised irrigated pasture with and without concentrate feeding; feedlots preceded by fertilised irrigated pasture or by extensive pasture; indoor housing throughout life or preceded by fertilised irrigated pasture or by extensive pasture; and semi-intensive silvopastoral system. The sustainability components for which there were some differences across these systems were: human health; welfare of production animals; efficiency of use of world resources: land usage; efficiency of use of world resources: land area per kg meat (conservation); efficiency of use of world resources: amount of conserved water per kg meat; greenhouse gas production per unit of product; extent of water pollution and nitrogen/phosphorus cycle disruption; biodiversity decline; and reduction in carbon sequestration (Broom 2021a). For example, degraded extensive pasture used most land per kilo of beef, semi-intensive silvopastoral used the least land and feedlot was intermediate. The totals of all sustainability components are shown in Table 1.

Table 1. Totals of sustainability components for each beef production system (modified after Broom 2021a)

As a result of this analysis, Conclusions 1-4 at the end of this paper concern beef production systems.

Sustainability comparisons of beef with other meat and with plant production

No comparable scientific analysis of all components of the sustainability of other meat and of plant production has been conducted. I hope that this work will be done. However, the data for lamb from extensively reared sheep would be similar to those from extensively-reared beef cattle. Estimates for pork, chicken and cultured meat are made here. Pork and chicken would score worse than beef for efficiency of use of world resources and significantly worse for production animal welfare but a little better for land area, water use, greenhouse gas and biodiversity decline. The overall sustainability score would be slightly worse (-2 estimated) for pork and chicken than for beef. This estimate contradicts the widely stated view, based largely on greenhouse gas production, that beef is less sustainable than pork and chicken. How will future judgements about sustainability be made? If efficiency of use of world resources or animal welfare is the most important component - beef and lamb are better than pork or chicken. If greenhouse gas, land area used, or biodiversity decline are the most important components - pork and chicken are better than beef or lamb. For each meat, the best systems are much more sustainable than the worst.

I have endeavoured to obtain information from three cultured meat producers that would enable me to do an analysis like that carried out for beef. None of the producers would give me sufficient information to allow the analysis to be carried out. Publications in this area are mainly written by those with a commercial interest in cultured meat production. My estimates for cultured meat suggest that it would be better than beef in land area, water use, biodiversity decline, and production animal welfare and not substantially worse in any components. Hence it could be more sustainable than beef, pork or chicken. However, a reliable replacement for fetal calf serum as an initial nutrient, a usable main nutrient source and safeguards for the spread of human and farm animal disease are needed. Tentative conclusions 5 and 6 follow the estimated comparisons of meat production systems.

How does the sustainability of eating meat compare with that of eating plant-based food? The efficiency of use of world resources is better by a factor of between 3 and 15 if plants are eaten rather than feeding the same plant material to animal species and then eating those animals. Plants can provide all essential human nutrients. A lot of protein in the US diet already comes from plants (8.7% from various breads, 7.2% from pasta, rice, potatoes and other vegetables, 4.5 from breakfast cereals etc. – a total of 32% as compared with 68% from animal sources (Pasiakos et al 2015). Comparable totals for a study in France were 31% of protein from plants, 69% from animals (de Gavelle et al 2017). However, as mentioned above, humans cannot eat most leaves, branches and roots and only some fruits and seeds. Leaves make up most of the plant food that is available to animals. As a consequence, mammals, birds, fish, insects etc. that eat leaves are more important as human food than seed or fruit eaters. World resource use is likely to rapidly become an important issue throughout the world and will have a major impact on livestock feeding. Plant cultivation systems also vary in sustainability. Some involve clearing natural vegetation and almost all involve killing native plants and animals.

What is likely to change in agriculture?

Changing farm animal diet, both that fed to livestock and that foraged by the animals, can reduce greenhouse-gas output and water use. However, the effects are relatively small. Feed additives, such as 3-hydroxy propanol and providing certain forage plants can reduce gut methanogen numbers or activity by 2-12% (White et al 2014, Feng and Kebreab 2020). Changing farm animal diet should be a rapid response in the production industry and there is likely to be greater reduction of output of methane and other greenhouse gases possible but not enough to solve the greenhouse gas problem. In addition, any changes must take account of reduction in anti-microbial resistance and be transparent and traceable (Maia de Souza et al 2017). System change is also needed for a fully sustainable future. A lot of studies focus on greenhouse-gas production (Kamilaris et al 2020) but all components of sustainability should be considered. It is likely that the components now widely considered to be of key importance: greenhouse-gas reduction and avoidance of poor welfare of livestock, will become even more important in the next few years. Using world resources efficiently by minimising waste of food and reducing use of livestock that compete directly with humans for food is very likely to become much more important. This would reverse the recent trend of increase in pig and poultry production. At the same time there would be increase in ruminant production, in production of herbivorous fish, and in production of some insects and other leaf eaters for human consumption. Pigs and poultry might return to their earlier role of consuming human food waste after it has been properly treated to avoid disease spread (zu Ermgassen et al 2016).

Biodiversity loss is an increasingly important factor for many of the general public who are driving these changes. Extensive pasture systems have higher biodiversity than irrigated pasture and most crops such as maize and soya have less biodiversity than pasture. Biodiversity of insects and birds is much higher on silvopastoral systems than on pasture areas in the same locality (Murgueitio et al 2008).

Biodiversity decline on farmed land has been greater in the last 15-20 years than ever before in world history. Much of the decline is a consequence of widespread herbicide use and some of it is a consequence of pesticide use. This decline involves the death of enormous numbers of animals and plants. The general questions of conservation and biodiversity decline have led to discussion about future aims. Should conservation be aimed at keeping islands of natural vegetation in a relatively barren world of agriculture (land-sparing) or should all land be biodiverse (land-sharing)? High productivity per unit of land allows more land to be spared for conservation (Balmford et al 2018, Balmford 2021). My personal view is that there should be some conserved areas managed to have only native communities of plants and animals but that the consequences that we see now of high production agriculture with very low biodiversity are too negative for wild animals and plants and for humans. Reducing biodiversity by causing the death of very many animals and other living organisms is morally wrong. Hence, both land-sparing and land-sharing are needed. Plant production methods need much more rigorous analysis so that unsustainable practices can be avoided. This might well be the greatest change in farming in forthcoming years.

In some areas, the use of semi-intensive silvopastoral systems, together with some entirely natural vegetation areas, is a good solution. Plant production from a mixture of herbs, shrubs and trees is much greater than from a single level pasture system. The use of nitrogen-fixing shrubs such as Leucaena as part of the forage for livestock, or as cut fodder, in semi-intensive silvopastoral systems can be economically successful and sustainable. As indicated in the analyses above there is typically: greater production and biodiversity; less pollution run-off because of water-holding properties of soil; less methane production per kg of meat; better carbon sequestration; less disease and better welfare in semi-intensive silvopastoral systems (Murgueitio et al 2008, Broom et al 2013, Broom 2017b).

Should you be vegetarian or vegan?

The answer to the question of whether or not an individual should be vegetarian or vegan depends on the reason for being, or becoming, vegetarian or vegan (Broom 2018). Reasons A, B, and C are briefly considered here.

A. “I cannot eat something that was once a live animal.” This is an aesthetic reason and is likely to persist if all food-production systems become sustainable.

B. “Eating animals is poor usage of world resources.” This is true for animals that compete with humans for food. Hence it is better to eat more plant food, to stop eating animals that eat food that humans can eat, or that comes from land where the plants humans eat can be grown, but to eat animals whose food is not edible for humans.

C. “I do not agree with killing animals in order that human food can be produced.” Very large numbers of animals are killed during crop production, during harvesting and during storage. For some crops the numbers are higher than for some animal production systems. Hence this is not a logical argument for being vegetarian or vegan.

Food from the sea and other open water

A final point concerns other changes in food production and other human activities, especially in relation to marine and other aquatic habitats. The chemical industry, building industry, clothing production industry, agriculture, human sewage and other human activities all cause pollution of the seas and open water that kills animals. There should be studies of the number of deaths of any animal per unit of pollutant and fines at a deterrent level linked to the number of deaths. A few examples are presented here. There has been a big decline in puffins, guillemots and terns because sand-eels have been fished for use as fertiliser. Albatrosses, dolphins etc. are killed in drift nets and other nets and are called “by-catch”. Several fishing methods are non-selective. They catch many animals that are not the target animals. Nonselective catching methods are morally condemned or are not permitted for most forms of vertebrate trapping. One of the worst fishing methods in this respect is trawling. While a few of the non-target animals caught are returned to the sea, very large numbers are injured or killed. Bottom-dwelling animals are particularly vulnerable. Plastic pollution in the sea has small effects on some species but very large effects on others. Legal redress is needed. Unwanted fishing gear also has large effects, killing many marine birds and mammals as well as fish and invertebrates. Penalties for leaving the fishing gear in the sea should be high but the identification of people who dump plastic or leave fishing gear in the sea is often difficult. As with food production on land, world resources are better used if people eat more aquatic plants.

Future livestock food production and feeding; some predictions

As the current trend to seriously consider the sustainability of human products and actions accelerates, what consequences for livestock food and feeding can be expected? Systems of production that cause poor welfare of the production animals, such as high production rates in broiler chickens and high milk yield in dairy cows, will be modified greatly and close confinement in systems that do not provide for the needs of sows, calves, etc., described by (Broom 2021b, 2022) will cease. The feeding of grain, soya, and other foods that humans can eat, to cattle and other ruminants will cease. Ruminant diets that reduce methane production will be refined and become universal. Systems for the management of livestock involving the animals foraging, or being fed cut forage from edible high protein leaves of trees, shrubs and pasture plants will increase. Poultry, pigs and other monogastrics will be fed less grain, soya and other human-edible material. Human food-waste treated to prevent disease spread will be fed to poultry and pigs. The overall effect will be a substantial decline in poultry and pig production. The farming of herbivorous fish will increase even faster then it has in recent years and fish and insect protein will become more important in the human diet. Cell-cultured food will become more widespread if no disease-risk or other sustainability issue prevents this.

Conclusions

1. Beef production systems have a wide sustainability range with the best much better than the worst.

2. The least sustainable beef production systems are extensive grazing that causes land degradation and the use of feedlots or indoor housing with grain feeding.

3. The most sustainable beef production systems are semi‐intensive silvopastoral systems. Well‐managed pasture‐fed beef from land where crop production is uneconomic is also sustainable.

4. For all meat and meat-like products, consumers need reliable sustainability labels taking account of all sustainability components. These would allow them to avoid purchase unless there is a sustainability label and to avoid the least sustainable meat.

5. Consumers should not avoid beef and lamb on grounds of overall sustainability, they should probably prefer beef and lamb to poultry and pig-meat.

6. Cultured meat may be more sustainable than beef, pork and chicken but reliable evidence is lacking.

7. The use of high-protein pasture plants, shrubs and trees should increase.

8. Use semi-intensive silvopastoral systems when possible.

9. Increase efficient use of extensive pasture.

10. Stop feeding maize, wheat, other cereals and soya to livestock, especially cattle.

11. Stop using feedlots and indoor housing of beef cattle.

12. Change dairy production to avoid high-producing cows and closely-confined calves.

13. Reduce pig and poultry production and increase sustainable beef and lamb.

14. Increase use of treated, unwanted human food for pigs, poultry, farmed fish.

15. Minimise ploughing and other soil-damaging activity.

16. Subsidise carbon-sequestration.

17. Switch fish-farming to the use of herbivorous fish: Tilapia, carp etc. Do not farm salmon, trout and other predatory species unless waste food is used.

18. Regulate human exploitation to prevent harms to world marine and other open water habitats. Develop exploitation of aquatic plants for human consumption.

Presented at the 2022 Animal Nutrition Conference of Canada. For information on the next edition, click here.