H.N. Le Houérou
The importance of browse trees and shrubs, especially in the arid, semi-arid and montane zones, is increasingly acknowledged throughout the world today, and more and more work is being carried out under various disciplines in this field.
The major value of browse trees and shrubs is that they provide protein, vitamins and frequently mineral elements which are lacking in grassland pastures during the dry and/or cold season.
They also enable standing feed reserves to be built up, so that herds are able to survive critical periods of shortfall or prolonged drought without losses.
Moreover, browse species are an effective means of utilizing marginal land on which normal crop production is ineffectual owing to climatic, topographic or edaphic constraints.
During the last 20 years many important research and development projects with a browse component have been implemented in various countries, in particular in Tunisia, Libya, Iran, Syria, Israel, France, Greece, Italy, Brazil, Chile, Mexico, the USA, Australia and South Africa.
Although many studies have revealed the major importance of browse in tropical Africa, few research and development programmes have been devoted to this topic, so far.
The aim of ILCA is to contribute to the promotion of research and development programmes on this subject since these will enable some major constraints to the development of the livestock sector in Africa to be lifted, especially as regards the drought evading strategies adopted in the Sahel and elsewhere.
Knowledge of browse species and their utilization by animals in Africa is certainly by no means insignificant, but it has often been published sporadically or only in part, in scattered contexts, and it is often qualitative and distributed or rather buried in a mass of literature (including several hundred documents) which often deal with pastoral problems in a general manner.
Moreover, a large proportion of this literature appears in the form of what have been called hidden documents, i.e. papers published in only a small number of copies, generally in mimeo form.
It therefore seemed appropriate, and completely in accordance with ILCA's mandate to disseminate knowledge, to make a synthesis of these documents accessible to the largest possible number of people in ILCA's two working languages, English and French.
I will now give a true example illustrating the reasons for holding this symposium. During the initial preparation phase in 1978 I asked a documentation service specializing in bibliographical searches to provide me with a list of references on browse trees and shrubs. After waiting many months I eventually received a list of 35 references, of which 5 had nothing to do with the subject concerned. If the present symposium has filled this gap, even if only partially, it will have achieved one of its objectives.
The sharing of experience by 50 or so scientists and technicians who are authorities on the subject and come from different ecological areas and continents seemed a powerful means by which to rake up ideas and stimulate research so as to achieve the targets which ILCA has been assigned: in other words to eliminate constraints to the development of livestock production in tropical Africa.
The interplay of ideas and experiences intended to allow better harmonization of methodologies and better coordination of research and extension programmes, so as to avoid as far as possible the duplication of work and promote better utilization of resources, as well as to initiate new cooperative programmes, exchange material and information, and finally, create awareness amongst decision makers and those responsible for defining livestock development and pastoral resource management policies.
A further 10 communications have been added to those presented at the symposium, enabling certain subjects to be better covered.
Overall, it seems reasonable to assume that the contributions presented in these proceedings represent the current state of knowledge on browse in Africa.
Vast gaps in our knowledge still remain, and suggestions have been put forward to establish the priorities for research and international cooperation.
Unfortunately, for purely material reasons it has been impossible to publish more than a summary of the lively discussions which took place over 5 days both during the working sessions and outside them. Nevertheless, the conclusions and recommendations, and their preamble, constitute what I believe to be a faithful reflection, although a highly condensed one, of the discussions and conclusions which emerged.
