Livestock feeding systems and the environment

Rapid population growth, in a context of scarce material and natural resources, is a common feature of developing countries. It is evident that appropriate and sufficiently productive agricultural technologies are needed urgently. Livestock production strategies and policies are needed which make optimum use of local resources without inflicting further damage on ecological environments already under pressure. However’ the role played by livestock in the overall farming system has been largely ignored.

Whilst technological transfer involving primarily Western models continues, research into the potential of regional resources is being neglected and social and economic constraints hindering innovative techniques are not being given adequate attention.

New livestock strategies are needed urgently; strategies which do not create import dependence but rather stress local needs, local resources, and identify the potential of indigenous breeds and feed resources.

Livestock and the “greenhouse effect”

It is generally agreed that the industrialised West has achieved a high rate of livestock productivity by using a disproportionate amount of the world’s resources, particularly fossil fuels, marine fisheries, and protein-rich cakes and meals. The efficient animal industries of industrialised countries would have been much less productive if their access to inputs, derived from fossil fuels, were as limited as those of the world’s poorer countries. Fossil fuels are too expensive for developing countries struggling with limited foreign exchange. Alternative and renewable energy sources have to be found.

Industrial countries are becoming increasingly aware of the environmental threat posed by fossil fuels and they are beginning to look for less destructive industrial and agricultural technologies. Rising world temperatures are causing growing concern and an awareness of the “greenhouse effect” is spreading. This is seen as a consequence of increases in levels of carbon dioxide, methane, CFCs and oxides of nitrogen. Carbon dioxide and methane are intimately related to plant growth and animal production. Methane contributes to heat retention in the earth’s atmosphere and reacts destructively with the ozone layer.

Herbivorous animals mainly cattle and buffalo, contribute 15-25% of the total global production of methane. With this in mind research priority has to be given to developing feeds for monogastric animals that can be derived from local tropical biomass such as sugar cane, water plants, and forage trees. These feeds use a minimum of fossil fuels and produce negligible quantities of methane.

The methane production factor in herbivorous animals means that ruminants must be given supplements to ensure efficient fermentative digestion. Research is also necessary for a better understanding of factors involved in the accumulation of CO2 and CH4 in the atmosphere. Agricultural development strategies at national and global level must aim at a reduction and eventual stabilisation of the principal ‘greenhouse gases”.

Planning livestock development programmes is critical and requires interdisciplinary cooperation. Action has to take place simultaneously on several fronts. Health, feeding, breeding and socio-economic aspects must all be considered and livestock and crop production must complement each other optimally.

The potential of lesser known species, micro-livestock and wildlife has to be explored and livestock production techniques must be selected which optimise long- and short-term benefits. In developing countries, Multiple Ovulation and Embryonic Transfer (MOET) and animal importation are likely to be less cost effective tools than artificial insemination (AI). AI can ensure genetic improvement and can be used as part of an integrated programme aimed at upgrading calving percentages and increasing survival rates in local herds. Local legislation can play an important role in ensuring the quality of inputs (vaccine and semen) and in setting realistic standards for local products such as meat and milk. Local legislation can also be used to ensure the supply of such valuable inputs as seeds and scientific information.

Research is essential to the future of livestock production in developing countries and one important issue is how to make the best use of animals for draught at the smallholder level. Research is needed on genetic improvement programmes for multi-purpose traits. Studies are needed into animal partition nutrients for work, foetal growth, lactation and the effects of reproduction. Finding the best feeding progammes for adaptation to available local resources are also areas requiring investigation.

The use of local feed resources

The question of feed resources is central and raises the issue of dependence on imported food, feeds and technological inputs. It is important that livestock feeding systems use locally available feed resources. These include feeds which can be produced using alternative cropping systems. Emphasis must be given to management systems and especially to the role supplementary feeding plays in optimising the use made of local resources.

A major problem arises in how to evaluate and use local feeds. Two categories are useful in identifying feed resources. First there are those basal feeds which provide the bulk of the diet and secondly there are those feeds which are high in nutritional content and which can be used as potential supplements.

Basal feeds should be allocated according to digestive requirements: fermentation (feeds rich in cell wall components such as crop residues, agro-industrial by-products’ and pasture) or intestinal gastric enzymes (sugars and starches such as those found in molasses’ sugar cane juice, and cereal grains). Supplements are recommended where nutritional deficiencies are likely in basal feeds. These supplements would usually be high in protein, examples being the vegetable protein meals from the oil seed industry, animal protein meals’ forage trees? shrubs and water plants.

The question of the chemical analyses needed in the initial formulation of diets based on these components is relevant here. Where pigs and poultry are concerned. important factors include protein elements, amino acid content, potential toxic compounds, such as fungal toxins for example and secondary plant components. Digestibility has also to be considered. In preparing ruminant diets attention has to be paid to soluble nitrogen, insoluble protein, rumen degradability, and the efficiency of the rumen ecosystem in relation to a particular feed. Attention must also be given to the rumen ammonia concentrations in animals fed basal diets. In the supplements fed to pigs and poultry, protein and amino acid content, secondary plant components and toxins should be carefully examined. The digestibility of the protein must also be considered. Where ruminant supplements are concerned, the important factors are insoluble protein and digestibility.

In general, it is useful if response curves can be established showing the relationship between levels of animal performance and the amount of the most limiting supplement added to the basal diet. This limiting supplement is frequently either an important or an expensive and/or scarce item. The results of such research will provide essential biological and economic data for future decision making.

Given the high cost of imported cereal grains, research must concentrate on finding an efficient and more cost effective way of using grain. In poultry diets this can be done by using a choice feeding system where whole grain, pelleted protein concentrates and a particle source of calcium carbonate are offered in the same trough. Restricted feeding of grain can be complemented by scavenging for protein and the productivity of free range village birds can be improved by giving strategic supplements.

Alternative feeds

More effective ways will have to be found of making use of alternative feeds based on sugar derived from molasses, sugar cane juices and starch derived from tubers, bananas, and plantains. More appropriate management systems must also be devised for liquid and semi-solid diets and further developments are needed in methods of satisfying amino acid requirements. Since many alternative diets contain no fibre, studies are also needed into the role of fibre. The question also arises of how best to exploit new sources of protein from trees, shrubs and water plants. Combinations of protein sources which form mixtures of high biological value (vegetable and animal protein) have to be identified, and promising new sources of animal protein, rich in lysine and methionine/cystine, such as earthworms and snails, must be evaluated.

Research in ruminant husbandry should stress the importance of optimising the efficiency of rumen fermentative digestion by maximising the rate of digestibility of fibre and ensuring adequate levels of rumen ammonia. Research is needed to develop response relationships to by-pass protein (locally available) before and after treatment, in order to increase by-pass characteristics. Research must also be done on ways of protecting soluble protein from being degraded in the rumen.

The strategic position of on-farm research must also be emphasised in relation to feed resources. Once knowledge has been accumulated, the quick est way to improve existing techniques is by on-farm experiments. An example of this might be substituting concentrates typical of the present feeding system for strategic supplements (ruminants) or alternative sources of “farm produced” carbohydrates (pigs and poultry). Their effects can then be monitored.

It is acknowledged that pasture and the role of livestock management require particular attention, especially where problems arise because land has been used too intensively in livestock production. If pasture use on limited land areas is to be intensified, the problem of dry season feed scarcity has to be overcome. Strategies which can make feed available during this period will have a great impact on animal productivity. Establishing “ banks “ providing fermentable big-mass, such as sugar cane, and both fermentable nitrogen and by-pass protein, in the form of forage shrubs and trees, is highly recommended.

The possibility of increasing wet season grassland productivity by introducing improved methods of species fertilisation should not be ignored. This would have to be complemented by practices which could ensure the continuity of feed supply during the dry season. Strategic nutrient packages molasses/urea blocks and pelleted by-pass protein could be used as dry season feed. These initiatives would result in a greater degree of self reliance and a reduction in dependence on supplements coming from outside the region.

Finally, a word about erosion. Erosion is recognised as an extremely serious consequence of overgrazing and several measures to combat it are available. These include removing ruminants from areas where erosion is taking place, and establishing land rehabilitation systems based on planting multi-purpose trees. Permanent stable grassland can be encouraged by actively discouraging tree clearing or tree harvesting unless there are tree reclamation or tree re-planting programmes. Finally, where overgrazing threatens, greater use must be made of full or semi-confinement management systems for all classes of livestock.