Man and beast - working together
As the cost of importing machinery, spare parts and fuel rises, the economic arguments for the use of animal energy as an essential part of a sustainable and self-sufficient national economic system should become more evident. In reality however, with the exception of the "oil crisis" during the mid-1970s, this source of energy has received little attention from policy makers and international organisations. Nevertheless, the vast majority of agricultural energy inputs in lesser developed nations are of animal origin. In many of these countries, man and beast work side-by-side to cultivate the land, transport loads and operate machines; and in many places human labour makes the larger contribution. A wide range of domestic animals are used for work; cattle, equines and buffaloes are some of the best known but this group also includes camels, yaks, dogs, reindeer, elephants and others. In addition, animal manure is utilised as a direct source of fuel or as a raw material in various types of bio-gas digesters.
The use of work animals is often billed as an intermediate technology, particularly suitable and really applicable to smallholder farmers only. Whilst this may be a truism in some cases, there is no reason why animal power could not be utilised, in combination with other power sources, for commercial operations. In fact this is quite often the best and most cost effective solution. There are a number of examples where this mixture of technology has been applied successfully. In Cameroon, for example, a large oil palm plantation uses carts pulled by trypano-tolerant N'dama cattle to transport the harvest to collection points. In Indonesia, teak logs are pulled out of the plantations by teams of oxen, whilst cattle have also been used successfully in forestry work in Central America, Chile, Malawi and Zimbabwe. In the Dominican Republic, a large sugarmill estate has continued to use oxen to transport sugarcane from fields to loading train stations. The company has found that it is not only cheaper than using motorised transport, but the use of oxen, in addition, reduces the compaction of the soil. As a result, the sugarcane replanting interval can be increased from five up to 6 - 7 years, providing a technical and an economic advantage of animal power.
Probably the most important contribution of work animals to land tillage operations is their traditional employment in ploughing. However, to optimise their contribution to crop husbandry practices this should be extended to include activities such as weeding and harvesting. There are, however, a variety of other practical benefits which can be obtained from animals beyond cultivation: animals can power machines, lift water for irrigation and transport goods or people. Farmers can also hire out their animals when they are not needed for farm work. The manure produced by work animals can be composted or used directly as an organic fertiliser (1 tonne of cattle manure contains about 8 kg of nitrogen, 4 kg of phosphate and 16 kg of potash). Alternatively, manure can be dried and burned as fuel or converted to biogas (25 kg of fresh cow dung produces approximately 1 m3 of methane which can be used as domestic fuel or to power gas-driven engines and pumps).
If income-generation related to the use of work animals is increased, farmers will be able to justify the cost of improving husbandry practices such as the provision of supplementary feeding, the provision of shelter and the use of better harnesses. As a result animals will be healthier and stronger and able to work year-round.