What can be done?

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Technologies

Technological change occurs as a response to changes in availability of inputs and in demand. Over the past decades the livestock sector has responded mainly by increasing efficiency and by the major structural shifts outlined earlier. There is little doubt that the sector will adopt and develop environmentally friendly technologies where policy makers provide a corresponding and consistent set of signals. On the whole, technologies which can address the environmental problems of livestock production are already available or are in sight.

Technologies which can work to the benefit of the environment, can be conveniently grouped into four different sets:

1. Technologies that simply reduce the environmental damage by alleviating the direct pressure on natural resources or by reducing the pollution load through modifying the chemical or physical characteristics of work products;
2. Technologies that enhance natural resources, i.e. that make them more productive or richer;
3. Technologies that save natural resources, that allow us to get more revenue from the same resource or to get the same from less;
4. Technologies that turn waste into products by closing cycles.

While admittedly there is some overlap among those categories, it brings clarity in what is meant by "beneficial to the environment" and it takes the focus away from the direct physical interaction between livestock and the environment, by introducing a more comprehensive picture of resource management.

Reduction of environmental damage

In the arid and semi-arid grazing areas, careful water development can help to prevent environmental damage. Any water development needs to be considered for its potential effect on distribution of seasonal grazing and settlement patterns. Investment in market technology may also reduce environmental pressure by encouraging greater off-take. In addition, new and more benign methods are now available to control diseases. Vaccines are available for tick-borne diseases spread by a number of sub-species, although not yet for East Coast Fever. Long duration tick sprays, which can be applied on individual animals (pour-on) now exist, and these have a negligible environmental effect. A number of environmentally benign control methods, which use extremely low concentrations of easily degradable insecticides, now exist for tsetse control, although the overall effect of tsetse clearance on the natural resource base remains in dispute.

Environmental damage control is of great importance for intensive systems. The environmental impact can be significantly reduced by focusing on emissions from manure by, for example, improving collection and storage techniques. The main focus should be on reducing nitrogen losses, most of which are in the form of ammonia from manure. Most losses can be avoided by manure collection and covered storage facilities. Minimal amounts of ammonia are emitted when manure is collected under solid floors, and 80 to 90 percent reductions can be achieved by covering storage tanks (Voorburg, 1994). A further reduction of odour and ammonia loads can be achieved through natural or forced ventilation systems or through bio-filters or bio-washers that absorb odours and ammonia from polluted air. This is done by oxidizing ammonia into NO2 and NO3. Up to half of the ammonia can be eliminated through such air washing systems which are, however, costly in investment and operation. (Chiumenti et al., 1994).

Nutrient losses during and after application of manure on soils can be significantly reduced by injection or application of manure into the subsoil (Brandjes et al., 1996). Better timing of application in response to crop requirements avoids further losses and enhances the nutritive value of manure. Nitrification inhibitors can be added to slurry to reduce leaching from the soil under wet conditions.

In tanneries, dairies and slaughterhouses, anaerobic systems can purify waste water and reduce by half the Biological Oxygen Demand (BOD), while more sophisticated anaerobic systems reach 90 percent BOD-purification (Verheijen et al., 1996). Waste water treatment usually first separates solids from the liquid, followed by biological treatment under anaerobic conditions (lagoons). Nutrients such as phosphorus, are then removed by chemical or physical processes such as adsorption, stripping or coagulation. The same process serves to remove the remaining BOD as well as pathogens. In a few developed countries environmental problems have already led to the establishment of high quality standards for discharge water. To meet these standards, a combination of anaerobic and aerobic methods is required, often coupled with nutrient removal systems. In slaughterhouses, the environmental impact can often be greatly reduced by employing a simple technology such as dry rendering of offal which reduces the amount of waste water produced. With reductions in water use the waste load decreases and wastes should be collected as solids wherever possible. Blood and paunch, and other solids, contribute enormously to the waste water load and should be prevented from being washed away by systematic collection.

Resource-enhancing technologies

For grazing systems in arid zones, "deferred grazing", which has been a traditional practice in many Middle Eastern countries, may regenerate the vegetation. For the semi-arid areas, overseeding or planting of adapted fodder, and the introduction of a multi-species grazing pattern, will often encourage better use of the vegetation and may have positive effects on plant and animal biodiversity. Such technologies may be part of overall "management" approaches, such as Holistic Resource Management, which consider the most appropriate tools for any particular site. Such management approaches should explicitly acknowledge the high efficiency of the current pastoralist systems and their pattern of dis-equilibrium (Behnke et al., 1993). For the humid tropics, perennial grasses and legumes have now been developed that maintain soil fertility better than any other crop. Biodiversity may also be enhanced through careful management of wildlife-livestock interactions in pastoral systems as well as through prevention of bush encroachment.

Livestock, mainly through their input function within a mixed crop-livestock system, enhance the main natural resource - land. Animal manure and traction make the land more productive than would be the case in their absence. Thus, all technologies that reduce nutrient losses from manure, and improve the efficiency of their application, enhance land productivity. This may be done, for example, by promoting stall feeding which doubles the effective availability of nitrogen and phosphorus. Fodder shrubs and trees may be introduced to reduce soil erosion and improve soil fertility. Several mixed farming systems have been developed using fodder shrubs and trees. An example are agroforestry systems with three strata, including grass, fodder shrubs, and tree crops such as oil and coconut palms or cashew nuts as successfully introduced in Indonesia.

Raising the productivity of already cultivated land through crop-livestock interaction reduces the overall land requirement to meet the demand for food and thereby protects other land from being brought into cultivation. In this indirect way, crop-livestock interactions foster biodiversity. It remains one of the most important avenues for intensification of agriculture and is certainly the most environmentally friendly. It is also creating important positive externalities which are usually not accounted for and are, in fact, very often restricted by overall policies working to their detriment.

Resource saving technologies

The livestock sector possesses and continues actively to develop, technologies that increase the efficiency of natural resource use. In particular, these technologies target feed conversion because feed is a major cost item, typically accounting for 60 to 70 percent of the production costs. Better feed conversion saves land used for its production while reducing the animals' waste load. But technologies also provide solutions to saving and sparing other natural resources such as water and biodiversity.

Box 3.3 Reducing methane emissions from digestive fermentation through strategic supplementation in South Asian countries.
Urea and other supplemental nutrients are mixed with molasses to make it palatable to livestock. In addition, molasses provides the energy needed in order to realize the improved microbial growth that can result from enhanced ammonia levels. These Multi-Nutrient Blocks (MNB) have been used in many countries including India, Pakistan, Indonesia and Bangladesh, Habib et al., (1991), Hendratno et al. (1991), Leng (1991) and Saadullah (1991). Typical results have been: milk yield increases of 20 to 30 percent; growth rate increase of 80 to 200 percent and increased reproductive efficiency. Based on these results, methane emissions per unit product went down by up to 40 percent. Bowman et al., (1992), estimated that strategic supplementation of dairy animals will reduce methane emissions by 25 percent while increasing milk production by 35 percent. The efficiency of digestion in the rumen requires a diet that contains essential nutrients for the fermentative micro-organisms. Lack of these nutrients lower animal productivity and raise methane emissions per unit of product. For animals on low quality feed, the primary limitation to efficient digestion is the concentration of ammonia in the rumen. Supplying ammonia can therefore greatly enhance digestive efficiency and utilisation of available feed energy. Ammonia can be supplied by urea, chicken manure or soluble protein that degrades in the rumen. Urea is broken down in the rumen to form ammonia, and adding urea to the diet has been the most effective method of boosting rumen ammonia levels.

There is a wide array of technologies that improve feed conversion. The most important ones are:

- Introduction of multi-phase feeding whereby feed composition is much better suited to the needs of animal classes. By better adjusting the nutrient supply to the needs of animals, less waste is produced and therefore less nitrogen and phosphates appear in waste and in the environment;
- Improving the accuracy of determining nitrogen and phosphate requirements, followed by a better balancing of feeds with these essential nutrients. In this respect, important gains have been obtained in a better balancing of pig and poultry rations in essential amino-acids, the building blocks of feed proteins. For example, a combination of better feed balancing, improved digestibility and inclusion of synthetic amino acids allows for a substantial reduction of the protein content in feed, and hence a reduction of nitrogen and phosphorus excretion by 20 to 40 percent (Van der Zijpp, 1991). Other options include the use of hormones for growth or milk production (bovine somatotropine or BST) or other stimulants (clenbuterol), frequently used in the USA but banned in Europe for public health considerations.
- Increasing diet digestibility has seen spectacular improvements with the addition of an enzyme (called phytase) which catalyses the digestion of phosphates contained in feed. The same enzyme might also increase the availability of zinc in feed thereby reducing the need for feed additives. This optimum nutrient ratio and composition management reduces the risk of loading the environment with these elements.
- Promoting feeding systems which reduce intake and stop buffet-style ad libitum feeding, popular in the eighties. Poultry, in particular, require feed of high energy and protein concentration for optimal production,. This has led to research to develop specific feed mixtures with higher protein content and the most appropriate amino-acid composition for poultry feed requirements.
- In mixed farming systems of lower intensities, strategic supplementation for specific classes of animals, such as lactating cows or growing animals, can greatly improve the efficiency of limited amounts of available feed. A basic technological approach to mitigate environmental damage is to improve feed production and quality, thereby reducing pressure on grazing areas and improving internal nutrient transfers.
- In addition to feed and nutrition, other technologies can improve feed conversion efficiency. These include enhanced genetic potential, better health and environmental conditions, and improved general livestock management.
- Increasing efficiencies in feed conversion for the livestock sector as a whole can be obtained through a shift to monogastrics as better feed converters, and to poultry and fish in particular. This trend is likely to continue, and will be particularly strong in the developing countries.

Bearing in mind that most expansion and productivity growth in the livestock sector will have to be based on concentrate feed, the main environmental challenge is to limit the land required for growing feed. This can only be done by productivity increases in both crop and livestock production. In that sense, biodiversity is best preserved by intensifying livestock production (aiming at better feed conversion) while also intensifying crop production (aiming at higher yields). Both will reduce the land requirement for given volumes of final product and will alleviate pressures on habitats and biodiversity as well as limit requirements for land and water resources.

Box 3.4 Alternatives to cereal feeding.
Countries in the humid and sub-humid tropics are cereal deficit countries. Livestock production, in particular monogastric production is thus faced with high prices for feed concentrates. This has spurred the development of sugarcane-based feeding systems (Preston and Leng, 1994) in a number of tropical countries (Colombia, Cuba, Vietnam, Philippines). Sugarcane is one of the highest yielders of biomass per unit time and area. Its juice can be used for monogastrics while the tops can be used in ruminant nutrition. As a perennial crop, sugarcane production has very low rates of erosion and can be produced with low external input. In the past, the association of sugar cane and livestock production has been problematic since sugarcane was traditionally produced on large plantations, geographically separated from livestock production. Recent developments on the diversified use of sugarcane may lead to more village-based intensive monogastric production systems in the humid tropics.

Increasing efficiencies also explain why, despite growing livestock populations, the global trend for methane emissions from livestock is to remain steady. The reasons for this stagnation are lower emission levels per animal and per unit of product, and the fact that monogastric production is growing at a much faster pace than ruminant production.

Waste technologies

Historically, the raison d'être for keeping livestock was its use of resources for which there was no alternative use. Waste land was turned into high value food. The characteristic of using resources of no or low opportunity cost also explains why efficiency per animal was not, and in many low input systems is still not, a major concern.

The conversion of organic waste into livestock products, although associated with livestock waste, reduces at the same time the environmental hazards associated with crop and agro-industrial waste. Also, food wastes are consumed by livestock and increasingly so, as urban agglomeration and changing eating habits offer a window of opportunity for the collection of food waste from catering units to be recycled as feed. Large amounts of straw, otherwise burned on the fields or slowly decomposing with little nutritional benefit to the crops, may be turned into quality feed, for example through urea treatment of feeds (Li Biagen, 1996).

The cycles of matter can also be closed by using livestock waste as feed, energy or fertilizer. The latter has already been discussed above. Recycling manure by feeding it to other animals, as well as fish (Muller, 1980), is practised only on a limited scale largely because of a widespread reluctance to use manure as feed. This originates mainly from fear of health risks but is also due to the low nutritive value of manure with the exception of that of poultry. Poultry manure is incorporated in to the diets of livestock in intensive systems and, particularly in Asia, manure is fed to fish and pigs (China). Poultry manure has reasonable quality when used as ruminant feed.

In intensive production systems, where large amounts of collectable manure are available, the low quality of manure as feed or high processing costs make its use as feed uncompetitive with commercial feed stuffs. In less intensive production systems where use of low quality feeds is common, high collection costs and opportunity costs (manure as fertilizer or fuel) prohibit the use of manure as feed. A recent overview of the possibilities is given by Sánchez (1995).

Technology also exists to make use of the energy content of manure. Biogas plants of all sizes and different levels of sophistication not only recover the energy contained in manure but also eliminate most of the animal and human health problems associated with contamination of waste by micro-organisms. Other methods of controlling the waste load are the purifying and drying of manure.

Box 3.5 Biogas in China
In China, more than 5.3 million rural biogas systems are in place, producing 1.25 million m3 annually. Biogas is used for household heating and cooking, poultry hatching, tea roasting, grain and fruit storage. The slurry is used for fertilizer, fish farming and for feeding pigs which show good results in the semi-intensive production systems (Henglian, 1995).

Promising approaches exist to reduce emissions from manure lagoons by recovering methane and using it for energy. Large confined animal operations allow for such techniques to be profitable. This methane can be used for on-farm energy to generate electricity and the slurry effluent can be used as animal feed, as aquaculture supplements, or as crop fertilizer. In addition, managed anaerobic decomposition reduces the environmental and human health problems often associated with manure management. The controlled bacterial decomposition of the volatile solids in manure reduces the potential for contamination from run-off, significantly reduces pathogen levels, removes most noxious odours and retains the organic nitrogen content of the manure.

Methane can be recovered in covered lagoons where manure solids are washed out of the livestock housing facilities with large quantities of water, and the resulting slurry flows into an anaerobic primary lagoon. However, such anaerobic conditions result in significant methane emissions, particularly in warm climates. Placing an impermeable floating cover over the lagoon and applying negative pressure recovers the methane which can be used as fuel or to generate electricity. Alternatively, digesters can be used. Large scale digesters are engineered vessels into which a mixture of manure and water is placed and retained for about 20 days. The digester is heated to about 60°C, after which the gas is drawn off and used for energy. Large dairy and pig farms with high energy requirements find these systems to be cost effective. Small scale digesters do not include heating and are appropriate for warm climates only.

Large scale manure processing is possible where intensive production is concentrated in certain zones, but it is often not economically viable. The efficient use of manure for feed and energy production entails high capital costs which often cannot be borne by individual farmers. Most processing waste can be turned into food, feed, fertilizer or energy. Slaughterhouse wastes can be composted and used as fertilizer. Anaerobic treatment results in a slurry that can be used as animal feed, the liquid part can be used as irrigation water, fish or algae production. Bones can be crushed, ground and prepared into bonemeal as feed.

In summary, improving the impact of livestock on the resource base is not constrained by the lack of technology, but more by the lack of an appropriate enabling environment, to allow these technologies to be adopted. The next chapter will provide the beginning of an action plan to promote such.

Next section Strategies for livestock production systems

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