Panos A. Konandreas, Frank M. Anderson and John C.M. Trail
ILCA Research Report No. 10
International Livestock Centre for Africa
September 1983
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ILCA PUBLICATIONS The International Livestock Centre for Africa (ILCA) is an autonomous, non-profit making research and information centre with a mandate to improve livestock production throughout sub-Saharan Africa. The activities and publications of the centre are financed by the Consultative Group on International Agricultural Research (CGIAR). The CGIAR members which have funded ILCA to date are the International Development Research Centre, the International Fund for Agricultural Development, the United Nations Development Programme, the World Bank, and the governments of Australia, Belgium, Denmark, the Federal Republic of Germany, France, Iran, Ireland, Italy, the Netherlands, Nigeria, Norway, Saudi Arabia, Sweden, Switzerland, the United Kingdom and the United States of America. Responsibility for ILCA publications rests solely with the centre and with such other parties as may be cited as joint authors. Until 1982, the centre's two main series of scientific publications were Systems Studies and Monographs. These two series have now been superseded by the present series of Research Report. |
ORIGINAL: ENGLISH
ABSTRACT
A dynamic and stochastic cattle simulation model is briefly described and validated for production conditions in a study area in Botswana using Tswana and Simmental × Tswana cattle. The performances of the two genotypes under various milking and supplementation policies are compared, and the economic trade-offs between milk and meat production presented. An optimum production strategy is defined, and policy options for the development of Botswana's dairying sector are outlined.
KEY WORDS
/Botswana//simulation//cattle//Tswana cattle//Simmental cattle//milk production//meat production//animal performance//dairy industry//production policies//economic analysis/
RESUME
Le présent ouvrage donne une brève description d'un modèle dynamique et stochastique de simulation de troupeau de bovine, validé dans les conditions de la production d'une zone d'étude au Botswana, avec des bovine Tswana et Simmental × Tswana. Les performances des deux génotypes gérés dans des conditions caractérisées par des politiques de traite et de complémentation différentes ainsi que les avantages compares des productions de fait et de viande ont été présentés. Une stratégie optimale de production a été définie et des options relatives aux politiques de développement du secteur laitier du Botswana ont été décrites dans les grandes lignes.
MOTS-CLES
/Botswana//simulation//bovin Tswana//bovin Simmental//production laitière//production de viande//performance animale//industrie laitière//politique de production//analyse économique/
PREFACE
Livestock researchers are often asked to provide technical advice to policy makers on issues where the data required for appraisal go beyond those provided by experimental results. In such cases the researchers are usually obliged to depend upon informal concepts or models of the system in question to tailor their available data to the particular questions being posed. This informal approach makes for particular difficulties when the questions concern problems requiring detailed projections of the productivity and response of livestock systems to a range of different interventions. The application of systems simulation techniques involving the use of an appropriate simulation model or models can often assist by providing quantitative estimates of systems performance which would not otherwise be obtainable.
Dairy products are a major import into Botswana. An important policy question recently posed to livestock researchers in the country concerned the extent to which these imports could be reduced by increasing milk production from indigenous and crossbred cattle in the country without impairing beef production. Beef production is the principal livestock product in Botswana and a major source of export income. A substantial body of data was available from research by the Animal Production Research Unit (APRU) in Botswana on the productivity of indigenous Tswana and Simmental × Tswana crossbred cattle kept under ranch conditions for beef production. Information on milk production from both genotypes was available through the indirect measure of calf growth. APRU researchers considered that by combining these data and the collective experience of APRU staff and others associated with livestock production in Botswana it would be possible to address the complex of issues related to dual-purpose beef and milk production through the application of a simulation model. The cattle herd dynamics model developed by ILCA was considered to be appropriate to the problem. Full details of this model are given in ILCA Research Report 2.
This Research Report summarizes the principal results of the application of the ILCA model to this Botswana policy question.
ACKNOWLEDGMENTS
This application of the ILCA model to a practical policy question was at the invitation of APRU in Botswana. Such applications are the proving grounds of the usefulness of systems simulation techniques and of this model in particular. For this reason the authors gratefully acknowledge both the invitation of APRU to undertake the work and the able assistance and enthusiasm of APRU staff in the course of the application of the model and in the preparation of this report. Special thanks are extended to N. Buck, T. Rose and D. Light and their assistants in APRU without whose detailed input and professionalism this application would not have been possible.
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3. The simulation model and specification of its driving variables
3.1 Forage on offer
3.2 Forage intake
3.3 Energy requirements
3.4 Growth and milk production
3.5 Mortality
3.6 Reproduction
3.7 Herd management regime
3.8 The simulation process and initial herd composition
4. Baseline run and model validation
5. Simulated performance of two genotypes under various milking and supplementation policies
5.1 Experimental design
5.2 Comparative simulated performance5.2.1 Fertility
5.2.2 Mortality
5.2.3 Animal growth
5.2.4 Feed inputs and milk and meat offtake
5.2.5 Herd viability
5.2.6 Overall comparative performance on the basis of energetic efficiency
6.1 Trade-offs between milk and meat production
6.2 Profit maximization and the optimum production strategy