|Livestock Research for Rural Development 2 (1) 1990||
Citation of this paper
Suggestions for intensive livestock-based smallholder systems in semi-arid areas of Tanzania
Swedish University of Agricultural Sciences,
Department of Animal Nutrition and Management,
Box 7024, S-750 07 Uppsala, Sweden.
Smallholder systems based on crop growing combined with stall-fed improved dairy cows or goats have been successfully developed in the high-potential areas of East Africa, and with certain modifications could be adapted to the semi-arid regions. As increasing population pressure results in progressively smaller agricultural holdings, and traditional grazing areas are taken over for crop growing, the introduction of more productive integrated intensive systems is imperative if total ecological and social collapse as a result of land degradation is to be avoided in the semi-arid areas. Maximum sustainable productivity can only be achieved by integrating intensive livestock keeping with crop production and agroforestry. Dry season fodder supply is the most limiting factor for livestock productivity in semi-arid areas, but the problem can be solved by a combination of conserved grasses and legumes, leaves and pods from trees or bushes and crop byproducts and household waste.
The integration of zero-grazed improved dairy cows and small livestock into smallholder systems results in increased availa- bility of milk, meat and other animal products, improved soil fertility, and removal of the risk of soil erosion as a result of overgrazing. One disadvantage of such systems, however, is the increased requirement for labour, although this could be reduced by the use of pairs of cows or donkeys for ploughing.
Key words: Integrated farming systems, Africa, fodder trees, erosion, zero grazing, sustainable systems, nutrition
A variety of highly productive small-scale intensive mixed farming systems have developed in East Africa, almost exclusively in areas of high population density where agricultural holdings had become too small to support traditional farming practices. These more intensive systems are generally based on crop growing, integrated with milk production from small herds of dairy cows or goats, and usually involve the recycling of organic matter in the form of crop residues and manure, and some form of agroforestry. Examples of such systems can be found in the Kenyan highlands, and in Tanzania, for example on the slopes of Mt. Kilimanjaro and on islands in Lake Victoria. These are all relatively high-potential areas, but similar systems are now developing in semi-arid central Tanzania in areas in which agro-pastoralism was the dominant agricultural form, and where uncontrolled overgrazing was the main factor leading to severe land degradation, threatening total ecological collapse. The seriousness of the situation resulted in the initiation of a far reaching, and in some respects unique programme - The HADO Project (Hifadhi Ardhi Dodoma - Dodoma Region Soil Conservation Project) (Christiansson et al 1987).
The HADO project was started in 1973 and was initially concerned with arresting the accelerating land degradation occurring in parts of Dodoma Region through physical soil conservation measures. However,it quickly became apparent that the terraces, bunds, cut-off drains etc. that had been constructed were not having the desired effect due to their destruction by grazing animals, and also due to uncontrolled water run-off from higher slopes denuded by over-grazing. As a result, a decision was taken in 1979 to close the most severely affected area, of over 1,200 km2 - the so called Kondoa Eroded Area - to all livestock, which involved the eviction of over 85,000 cattle, goats, sheep and donkeys. A smaller area of just over 700 km2 to the south of Dodoma town was destocked in 1986.
The regeneration of the vegetation, and the arrest of ecological degradation generally in these areas has been dramatic. However, the livestock owners were originally given to understand that some form of livestock keeping would be allowed when the land had recovered, and as it is generally accepted that attempting to restrict herd sizes under traditional extensive grazing systems would not have been possible. Some form of restricted grazing or stall-feeding (zero-grazing) system was left as the only reasonable alternative. Accordingly, a number of preconditions for the reintroduction of cattle were proposed:
A number of smallholders have now satisfied these conditions, and have purchased improved dairy heifers. The performance of the holdings and the problems experienced will be monitored as part of a long-term research programme.
Suggested livestock-based smallholder systems for the hado area
The term "semi-arid" need not be precisely defined here, but it is assumed that rainfall is sufficient for crop growing to be a major activity. In the HADO areas, and similar areas of East Africa, mean annual rainfall amounts to 500-800 mm, and follows a bimodal pattern, with two short, intense rainy periods and a long, dry season. The total productivity of smallholder systems in such semi-arid areas would generally increase in proportion to the amount of rainfall, all other factors being equal.
As smallholder systems tend to be very labour intensive, high yielding, improved animals are essential. For them to reach their full genetic potential, strict disease and parasite control is necessary, as is the provision of secure, year-round feed supplies, with careful balancing of the different components of the diet in order to achieve maximum productivity and efficiency of feed utilization. It is important to emphasize that the success of such systems depends on the adoption of a complete package - ie the various interdependent components of the system are all essential for sustainable high productivity.
1. The animal component
1.1. Improved Dairy Cows
One or two upgraded dairy cows will be the central feature of smallholdings in the HADO areas, providing cash income from sales of milk surplus to the family's requirements, and heifers not needed as replacements. On a typical smallholding in a semi-arid area of Tanzania, assuming an improved environment with respect to feed quantity and quality, disease and parasite control, and physical factors such as provision of adequate shade and water, the most productive type of animal would probably be a Zebu x Exotic cross, with the percentage of exotic blood being directly proportional to the quality of the environment. From experiences elsewhere it is likely that the optimum level of exotic blood would be around 50%, possibly higher where management standards and feed quality are good, and the climate not too harsh. Ideally, the exotic should be a large-bodied breed, such as the Friesian, sothat the crosses would be suitable for draught purposes, and male calves not wanted for breeding could be reared for meat. Upgrading using artificial insemination is possible in the more accessible areas, but would obviously pose problems in the remoter regions, as would using exotic bulls for natural mating. An alternative approach could be to use a dual purpose breed developed in a similar environment, such as the Mpwapwa breed from central Tanzania, which is based on the Sahiwal, Ayrshire and improved East African Zebu breeds.
Traditionally cows in Africa have not been widely used for ploughing, presumably being considered to be too weak. Where animals have been used, oxen have been preferred, but this means that their usefulness is limited to the ploughing season, although they must be supplied with feed all the year round. However, pairs of well-fed, healthy cows, particularly the large-bodied types, should be quite capable of meeting the draught-power requirements of smallholdings, especially if techniques such as mulching and the recycling of manure have been applied, increasing the organic matter of the soils and thus making them easier to work. Research in countries where a considerable proportion of draught animal power is derived from cows has shown that milk yields (Lawrence 1985) and calf growth rates (Munzinger 1982) are not significantly reduced, provided that the cows are adequately fed when working.
1.2. The calf
As male calves not required for breeding would be slaughtered for meat, both a large-bodied type, and a milking system which allows rapid calf growth are necessary for a successful calf rearing system. Restricted suckling - using the calf to initiate milk let-down, which can otherwise be a problem in cows with more than 50% Zebu blood, and then allowing it access to the cow after hand milking - has been shown to significantly improve calf growth rates, particularly on poor quality rations, and to increase total milk yield and reduce the incidence of mastitis (Preston and Leng 1987).
1.3. Small ruminants
Sheep and goats are essential components of pastoralists' herds, partly due to their abilty to withstand drought conditions and,in the case of goats, due to their preference for browse, which means that they do not compete with cattle for available biomass. Although small ruminants would not be essential in a smallholder system, goats, tethered and grazed, or housed and fed on low quality crop residues and household waste, have, due to their smaller body size, obvious advantages over cattle as sources of meat and cash income. Zero-grazed exotic dairy goats are also an alternative, particularly in the drier areas, although they are probably less attractive than cows on all but the smallest holdings due to their susceptibility to parasites and higher requirements for both labour and more sophisticated housing.
1.4. Poultry, pigs and rabbits
These small monogastrics would be useful additions to smallholdings for a variety of reasons. Their main function would be as consumers of household waste and various by-products, providing meat, manure, and in addition eggs in the case of poultry and skins in the case of rabbits. Chickens are particularly attractive, as specialized housing need not be provided, although if they were confined, the manure could be collected and used as a supplement in dairy cow rations, being a valuable source of non-protein nitrogen. Rabbits lack the homing instinct, and must therefore be confined, but have an advantage over other small non-ruminants in that they can efficiently utilize fibrous plant materials. Pigs are omnivorous, converting a wide variety of waste feedstuffs of both plant and animal origin to meat. They would probably need to be confined in a smallholder system, but could be used to clear fields of root crops after harvesting, thus assisting in land preparation. All these species have obvious reproductive advantages over domestic ruminants.
Donkeys are an alternative source of draught power, hauling small carts, carrying water, or produce to market, and in North Africa are even used for ploughing, although they have an obvious disadvantage compared to ruminants in that they are not normally eaten.
2. Feeding strategies
Fodder supply during the dry season is the most important single factor limiting livestock productivity in the semi-arid areas of East Africa. In nomadic pastoral systems the problem is solved by moving the herds vast distances in the constant search for pasture, whereas in the smallholder system most of the feed can be brought to the animal. There are several important benefits associated with this, both in the context of soil erosion and fertility, and also in relation to productivity and feed utilization, compared to extensive grazing:
Some form of restricted grazing is an alternative possibility, involving for example rotational grazing of small, improved, fenced pastures. The advantages of such systems are that once the pastures have been fenced and established, labour requirements are lower than for a zero-grazing system, although maintenance of sown grass/legume pastures requires considerable inputs. Other disadvantages of restricted-grazing systems include increased exposure of the animals to parasites, loss of manure, and the risk of soil compaction.
The range of potential animal feeds available on a smallholding will vary with local soil and climatic conditions, but a feeding strategy for both wet and dry seasons could be based on the the following components:
|Wet season||Dry season|
|1. Improved grass/legume pastures, grazed or cut and fed fresh||Grass/legume pastures cut andconserved as hay (or silage) or left as standing hay|
|2. Leaves from legume trees and bushes||Leaves and pods from legumetrees and bushes|
|3. Fresh leaves from growing crops||Dried crop residues and by-Products|
|4. Agro-industrial by-products, poultry manure, urea/molasses etc.||Agro-industrial by-products,poultry manure, urea/molassesetc.|
Each of these components will be considered in more detail below;
2.1 Improved grass/legume pastures
In addition to providing fodder for animals, grasses and legumes have a vital function on erosion-prone smallholdings in binding and strengthening bunds and terraces, and providing year-round vegetative cover, thus reducing run-off erosion. Whether the improvement of native pastures through bush clearing and oversowing, or the planting of mixed grass/ legume stands is justified on an individual holding would depend on various factors, in particular the size of the holding, or more precisely the area available over that required for food crops. The most suitable grass and legume species will depend on local climatic and soil conditions, and in the semi-arid areas of East Africa could include, for example:
However there are considerable difficulties in maintaining sown grass/legume pastures in the semi-arid tropics unless they consist of adapted species, are adequately fertilized, and are not overgrazed. In addition to their higher digestibility and protein, mineral and lipid content, legumes also increase the dry matter production of the associated grasses by raising soil nitrogen concentrations. Legumes also tend to be deeper rooted than grasses, and continue to grow longer into the dry season.
Conservation by making hay usually involves losses of at least 25% of the original material, and as the forage should be harvested well before maturity, before digestibility and nutrient content has started to decline, drying conditions are often unsuitable, and the risk of moulding and loss of nutrients by leaching is high. Harvesting towards the end of the rainy season, however, means that although total yields may be higher, the forage is at an advanced stage of maturity, and digestibility and feeding value are considerably reduced, and this also applies to standing hay. Digestibility and feed intake of dried, low quality forages can be improved by, for example, chopping or treating with alkali or urea, but these techniques are usually difficult to apply on a small scale.
The technique of ensiling forage has one important advantage over haymaking in that the forage can be harvested well before maturity, when digestibility and nutrient contents are still high. However, tropical grasses usually have too low a sugar content for ensiling, although immature maize or sorghum can be used. Another problem is that a certain minimum quantity of material is required, and it may be necessary for small farmers to make silage on a communal basis. A promising technique for preserving straw by "ensiling" with chicken manure or animal urine has been developed in Bangladesh (Davis et al 1983).
2.2 Leaves and pods from legume trees and bushes
Legume trees must be considered essential components of animal-based smallholder systems in semi-arid areas for a variety of reasons. In addition to reducing soil erosion and improving soil structure and fertility, the deeper roots of legume trees allow exploitation of the reserves of water and minerals lower down in the soil profile, providing green biomass of high digestibility and nutritive value throughout the year. Supplements of up to 30% of the diet with leaves and pods from legume tree species such as Gliricidia, Leucaena, Prosopis and Sesbania, which contain around 25-30% protein, much of it in a protected form which is used more efficiently, can produce considerable increases in milk yields of cows fed on basal diets of hay or dried crop residues. Shade trees such as Acacia albida drop up to 5 tonnes/ha of protein-rich pods at the end of the dry season, and as this particular variety sheds its leaves at the beginning of the rainy season it does not compete with growing crops or pasture for light.
2.3. Leaves from growing crops and crop residues
In China, farmers traditionally cut off the green tops of the maize plants immediately above the highest cob several weeks before harvesting for use as animal feed, and in Ethiopia the lower sorghum leaves are stripped off during the growing season (personal observation). At this stage the leaves are more digestible and have a higher nutritional value, and in both instances the effect on crop yields is said to be minimal. In the dry season, dried crop residues such as maize and sorghum stover are of low nutritional value, and digestibilty and voluntary feed intake are also low, but can be improved by, for example, chopping or soaking in dilute alkali and supplementing with leaves from legume trees or crops such as cowpea or pigeon pea vines.
2.4. Agro-industrial by-products, miscellaneous feeds and supplements
The availability of these potentially very useful feedstuffs is often seasonal and localized. Agro-industrial by-products, such as maize bran and rice polishings are relatively expensive, and may be used more economically by monogastrics such as laying hens or pigs, but the increase in milk yields resulting from their use in dairy rations makes them extremely valuable dry season supplements for lactating ruminants. Molasses/urea/mineral blocks, if available, can result in significant improvements in the productivity of, in particular, cows on poor quality dry-season diets, and poultry manure is also an excellent low cost source of non-protein nitrogen and minerals.
The total productivity of smallholder systems in the semi-arid areas of East Africa can be increased considerably, but only provided that a complete package of technical innovations and improvements is adopted. For example, introduction of upgraded dairy cows would be unsuccessful unless accompanied by simultaneous improvements in housing and parasite and disease control, and the provision of high-quality, correctly balanced diets. The emphasis must always be on sustainability, which can only be attained if the unit is in ecological balance, which requires the recycling of soil nutrients and organic matter, maintenance of soil fertility and prevention of soil erosion. The transition from traditional extensive, to more intensive forms of mixed agriculture in Africa has in the past been a gradual, long-term process, but time is a luxury that the people of the vulnerable, semi-arid lands of East Africa do not possess.
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