Farming systems can be roughly divided into on the one hand large scale, highly mechanized and energy intensive systems managed as corporate agri-businesses and on the other hand small-scale farms, which employ family labour and use limited external inputs. In the small systems, a closer integration of the different components, recycling and optimized use of local resources can enhance productivity. This approach aims to imitate the functioning of natural ecosystems, which are sustainable, primarily because the inputs are provided by nature. In the small integrated farm the livestock component has a central role to play. In addition to providing meat and other animal produce the animals are important for the recycling of residues and wastes, converting these from sources of pollution into valuable inputs such as organic fertilizer or biogas. The selection of appropriate livestock species is therefore an important consideration in the development of an integrated farming system. This article argues that smaller species of animals are more appropriate than larger ones.
LEISA Magazine • 21.3 • September 2005
Farming systems can be roughly divided into on the one hand large scale, highly mechanized and energy intensive systems managed as corporate agri-businesses and on the other hand small-scale farms, which employ family labour and use limited external inputs.
In the small systems, a closer integration of the different components, recycling and optimized use of local resources can enhance productivity. This approach aims to imitate the functioning of natural ecosystems, which are sustainable, primarily because the inputs are provided by nature. In the small integrated farm the livestock component has a central role to play.
In addition to providing meat and other animal produce the animals are important for the recycling of residues and wastes, converting these from sources of pollution into valuable inputs such as organic fertilizer or biogas.
The selection of appropriate livestock species is therefore an important consideration in the development of an integrated farming system. This article argues that smaller species of animals are more appropriate than larger ones.
In a farming system the components to be considered include the cropping system, the animal system and the management of the whole farming system, as well as the recycling of animal manure.
Prior to the industrialization of agriculture and the increasing dependency on oil, farming practices were in general more sustainable, simply because fewer external inputs were available. Soil fertility was maintained though fallow, use of leguminous plants either in mixed swards or as rotational crops and livestock often played a valuable role as a source of manure, and to provide the power for soil cultivation and for transport.
These basic features of sustainable farming systems are still relevant, but can be considerably enhanced in the light of new knowledge and opportunities. The opportunity is to be found at the heart of the energy crisis, which will result from the reduced availability of oil. This will mean that farm-produced energy will have increasing value as one of the outputs of the farming system, and as a replacement for previously purchased energy (liquefied gas or kerosene).
Fibrous biomass is likely to be one of the most important sources of alternatives to oil. This creates an opportunity for more diversified cropping systems and especially the promotion of perennial tree crops, many of which fix atmospheric nitrogen, and of sugarcane, which is the most efficient of all crops for converting water and carbon dioxide into biomass through photosynthesis.
Pasture is not an option as it is almost impossible to economically recover the fibrous components not eaten by the grazing animal. “Cut-and-carry” systems facilitate the separation of biomass into edible (leaves for feed) and non-edible (branches and stem for energy) components. This in turn will put emphasis on those crops which are easy to harvest and need less time and effort to cut and carry the biomass to the point of utilization. When this is taken into consideration, it is found that farmers prefer Gliricidia, mulberry and cassava over Leucaena, because of the greater time required to harvest a given weight of Leucaena compared with the foliages of the others. As well as feed and fuel, small farms should also produce materials that can be used to meet the construction needs of the family and their livestock.
This points once again to the advantages of crops that have multi-purpose uses. Thus, from sugarcane, the dry leaves can be used as roofing material (see later section), the juice as energy feed for pigs, the bagasse for fuel energy and for bedding, and the tops (leaves plus growing points) for goats and sheep.
As in the pre-oil age, livestock will be an integral component of the new farming systems. In addition, the proposed cropping systems will provide comparative advantages for the smaller livestock species, especially goats, sheep, rabbits and pigs. The overhanging threat of bird flu, with the potential to spread from South-East Asia to the rest of the world through migratory birds, puts a serious question mark over the future of poultry other than in a minor scavenging role, the loss of which will not prejudice the economic viability of the overall farming system.
Beyond the classical arguments for small livestock species – lower investment, facility in marketing the products, adaptation to the management skills of women and children – can be added the appropriate nature of their feeding behaviour and digestive system for utilizing the products of the crops that will have new significance as joint producers of feed, energy and construction materials, in integrated farming systems.
The browsing habits of goats make them especially suited to consume the foliages of tree crops, the stems and branches of which will be the feedstock for electricity generation through gasification. By contrast, the grazing preferences of sheep will often be satisfied by the herbage available on the ground in the tree plantation. They have also proved to be especially suitable for grazing the access paths among plots of sugarcane, as they do not find standing cane an attractive feed source.
In lowest income families, pigs are often managed as scavenging animals; however, apart from the difficulty in controlling them and preventing damage to crops, scavenging systems also make inefficient use of manure. When energy is at a premium, the opportunity to convert pig manure into biogas for cooking and effluent for fertilizer for crops and fish ponds, will be equally, if not more, important as the income from the sale of the animals.
This leads to the question of which breeds or strains of livestock will be most appropriate in the integrated farming system. Local “unimproved” breeds are usually viewed negatively by the animal scientist, because of their low rates of growth or of milk production. However, for an animal to express its genetic potential for high productivity requires feeds of high nutritional value, and these are usually not the feeds that can be produced when the available resources are solar energy, soil and water, with minimum external inputs. An equally important point in this equation is that purchased “high performance” feeds are highly digestible, which means that less manure is produced, than if local feeds of lower digestibility (and lower cost) are used. Less manure results in less biogas and less fertilizer. When the added value from the manure is taken into account, animals of lower productivity may be more appropriate.
Rabbits are one of the small livestock species whose unique digestive system has not been adequately exploited by conventional research. Like other hind-gut fermenters such as the horse and deer, rabbits have the combined advantage of the monogastric and ruminant modes of digestion. Unlike in other livestock species, a low content of fibre in the feed leads to poorer feed utilization efficiency. These physiological advantages are not utilized in the typical systems used in the industrialized countries where feeds for rabbits mainly consist of cereals and oilseed meals. In contrast, recent research in South- East Asia is showing that acceptable levels of performance in rabbits can be achieved with diets of 100 percent foliage derived from a crop (water spinach – Ipomoea aquatica) with a very high biomass productivity, and capacity to use organic manures efficiently. This research, which is especially relevant in the context of small scale integrated farming systems, is leading to increasing interest in rabbit production in South-East Asian countries, where the threat of renewed outbreaks of bird flu has stimulated the search for alternatives to poultry meat.
Small animal species are as subject to disease constraints as the larger species. However, when the interaction of the species with the other components of the environment – nutrition, housing and management – is taken into account then goats certainly, and sheep to some extent, present comparative advantages in terms of susceptibility to internal parasites.
In a number of studies it has been shown that when goats are managed in a “cut and carry” system, in which the feeds are foliages of trees and shrubs (as opposed to grasses) then the incidence of intestinal nematode parasites is negligible, making the regular use of chemical de-worming unnecessary. The main reasons appear to be that the infective nematode larvae do not develop in the foliage of trees and shrubs, but need the specific micro-environment found in grass swards.
A secondary factor may be the presence of tannin-like compounds in the leaves of shrubs such as cassava. Whatever the reason, goats in an intensive “cut and carry” system making use of tree and shrub foliages as the feed, are less prone to infections by parasite nematodes, than when they are managed under extensive grazing.
When land is in scarce supply, as is invariably the case in small scale family farming systems, grazing is rarely a management option. Even in upland areas, where land resources are more plentiful, farmers generally find it convenient to house their animals at night time, for their protection and because this facilitates the collection of the manure.
A general advantage of small livestock species is that their housing needs are simple. The production of modern construction materials, such as cement and bricks are energy-dependent and prices will eventually rise in line with the oil price. In most countries, and especially those in tropical latitudes, all the construction materials required for housing of goats, sheep and rabbits can be grown on the farm and are recyclable. In the design of housing for small livestock species, the first consideration should be the provision of an efficient means to recycle the wastes.
Recycling of manure
The manure from different animal species has different physical and biological characteristics which must be taken into account when deciding on which recycling method to use. The excreta from pigs and people is offensive to handle and it is best processed through a closed biodigester. The manure from goats, sheep and rabbits is not offensive, but it is not a suitable substrate in a simple biodigester system (see LEISA Magazine 21.1).
The pellet-like nature of the manure causes it to float on the surface of the liquid inside the biodigester, and scum formation becomes a problem. This kind of manure is better recycled through earthworms. It is convenient to house sheep, goats and rabbits on raised slatted floors. It is then a simple procedure to add some earthworms to the manure that has fallen through the floors. Any feed residues can be combined with the manure. Irrigating the earthworm beds with the effluent from the biodigester will speed up the process of decomposition and growth of the worms. The residue from this process (vermicompost) can be removed at intervals and used directly as fertilizer.
In a world faced with declining oil supplies, the comparative advantage will shift from large scale, oil dependent, farms to small scale integrated farms producing most of their needs, including energy, from natural resources. In such a scenario, small livestock species, especially pigs, goats, sheep and rabbits are the most useful animals, in particular in view of the low investment, reduced risk, adaptation to recycling systems, capacity to use local feeds and easy management by family members.