After decades of promoting the use of high-grade exotic breeds to increase animal productivity, researchers and farmers in tropical regions are reassessing the contributions of local breeds to food production.
Small-holder farmers commonly raise tropical Bos indicus or zebu cattle breeds for multiple purposes. In almost all production systems in sub-Saharan Africa, zebu cattle produce both milk and meat, and some breeds, like the Ngaundere Gudali in Cameroon and Nigeria, are used for traction as well.
The zebus' yields of milk and meat are relatively low, largely because they have not been as rigorously selected for one output as have the temperate Bos taurus breeds. Living in the tropics, however, they have acquired, through natural selection, adaptive traits which enable them not only to survive in a harsh environment but also to produce calves, milk and draught power. They are hardy and usually docile, will trek long distances for grazing-sometimes without a drop of water for two to three days-and can withstand high disease challenges.
In contrast, the high-producing exotic taurine breeds are often not viable in the tropics. Exposed to high disease challenge and insufficient feed, their productivity decreases markedly, and many eventually succumb to environmental stress. Crossbreeds with Bos indicus are hardier than pure exotics, thanks to specific adaptive traits inherited from their local parents. But they still require substantial feed and veterinary inputs to survive and to maintain reasonably high productivity in tropical environments.
In the cool tropics, farmers, who have the necessary resources to provide these inputs, tend to go for crossbred dairy cattle, especially if there is a well-developed market for milk. In the cool East African highlands, where cultivation is usually done with animal power, farmers may even use crossbred cows for both traction and milk production. Recently, Ethiopia imported 100 crossbred cows from Kenya for on-farm testing of their performance as traction and milk-producing animals.
Despite their higher production, there are not as many crossbred animals in sub-Saharan Africa as one would have expected. Except for a few countries where the delivery of artificial insemination services has been privatized, increasing the stocks of crossbreeds has generally proved to be a Herculean task. According to farmers, the high mortality rates of the calves produced, and frequent disruption of crossbreeding programs for political and economic reasons, have eroded the benefits of promoting crossbred cows. Mortality rates are high, particularly where extension of improved feeding and management packages for crossbreeds has been slow.
Notwithstanding, demographic and economic growth in the developing regions demand that livestock production be substantially increased. To increase milk and meat production from ruminants, two options are likely to be pursued in parallel: Where crossbreeding already forms the basis of market-oriented dairy production, such as in Kenya, research and development efforts will focus on promoting an increased use of improved dairy cows by generating and extending feeding and management packages suitable for small-holder conditions. Where resources are limited, attention will be given to increasing the meat and milk output of local breeds by increasing the efficiency with which they use locally available feed and other inputs.
Fed on feeds that either have a high fiber content or anti-nutritional factors or both, and which vary in quantity from season to season, local zebus usually direct the nutrients they are able to extract from these feeds toward the build-up of body reserves for use in times of feed scarcity. Their milk yields are low, barely enough to feed their own calves and leave some milk for the farmers' children.
Since no cow has as yet been designed to produce milk without a calf, the challenge for researchers is to improve nutrient utilization by zebus in a way that would enable them to have calves more frequently and also more milk per lactation. Male calves could be fattened before sale, which would bring in more money to the producers since they would be able to sell the animals on the more lucrative urban markets.
Where local breeds are concerned, "better" feeding does not necessarily mean feeding more high-energy feed. What matters more is the genetic potential of a given breed for milk, meat or traction and on how well the breed is adapted to produce these products from local feeds.
At present, zebu cattle account for most of the meat and milk produced in the tropics, and they will most likely continue to be used for animal food production where introduction of grade animals would not be sustainable. What research thus needs to do is to make them as efficient in producing food from available feeds as it is biologically possible. Since tropical animals seem to adapt to marked seasonal fluctuation of food quantity and quality by storing energy as fat, investigations are in process to determine how energy carried "on the back," can profitably be converted into more meat or milk without compromising their adaptive strategies.
The International Livestock Research Institute (ILRI) provides national crossbreeding programs with information on the productive and adaptive traits of indigenous breeds, thus helping the national programs decide which valuable genes need to be conserved in more efficient production systems or sperm banks.
Once researchers understand the exact nature of the trade-off between adaptation and productivity in tropical zebus, they will be able to select for those individuals that are genetically predisposed to increase their outputs of meat and milk. Moreover, it may be possible to manipulate the relationships between productivity and adaptability in such a way that the animals produce calves for fattening and milk at the time the farmer wants these products.
Indigenous breeds, long part of Africa's past, can contribute more to food security on the continent by better matching their production potential with locally available feed resources. Better utilization of local breeds in local production systems will also help conserve the valuable adaptation traits of these breeds that may otherwise disappear.
(ILRI Newsfeature)