TOWARDS INCREASED USE OF TRYPANOTOLERANCE: CURRENT RESEARCH AND FUTURE DIRECTIONS PROCEEDINGS OF A WORKSHOP ORGANIZED JOINTLY BY THE INTERNATIONAL LABORATORY FOR RESEARCH ON ANIMAL DISEASES AND THE INTERNATIONAL LIVESTOCK CENTRE FOR AFRICA HELD AT ILRAD, NAIROBI, KENYA 26–29 APRIL 1993 Edited by G.J. Rowlands A.J. Teale THE INTERNATIONAL LABORATORY THE INTERNATIONAL LIVESTOCK FOR RESEARCH ON ANIMAL DISEASES CENTRE FOR AFRICA BOX 30709 • NAIROBI • KENYA BOX 5689 • ADDIS ABABA • ETHIOPIA The International Laboratory for Research on Animal Diseases (ILRAD) was established in 1973 with a global mandate to develop effective control measures for livestock diseases that seriously limit world food production. ILRAD’s research program focuses on animal trypanosomiasis and tick-borne diseases, particularly theileriosis (East Coast fever). The International Livestock Centre for Africa (ILCA) was established in 1974 with a mandate to assist national efforts which aim to effect a change in the production and marketing systems in tropical Africa so as to increase the sustained yield and output of livestock products and improve the quality of life of the people in this region. Research under one of ILCA’s research themes addresses issues of livestock production under trypanosomiasis risk with particular emphasis on trypanotolerant livestock. ILRAD and ILCA are two of 18 centres in a worldwide agricultural research network sponsored by the Consultative Group on International Agricultural Research. In 1993 ILRAD and ILCA received funding from the African Development Bank, the European Union, the Organization of Petroleum Exporting Countries, the United Nations Development Programme, the World Bank and the governments of Australia, Austria, Belgium, Canada, Denmark, France, Germany, Ireland, Italy, Japan, Luxembourg, the Netherlands, Nigeria, Norway, Sweden, Switzerland, the United Kingdom and the United States of America. ILRAD and ILCA are due to merge into a single international livestock research institute on 1 January 1995. Production Editor: Peter Werehire This publication was typeset on a microcomputer and the final pages produced on a laser printer at ILRAD, P.O. Box 30709, Nairobi, Kenya, telephone 254 (2) 630743, fax 254 (2) 631499, e-mail BT GOLD TYMNET CGI017. Colour separations for cover were done by PrePress Productions, P.O. Box 41921, Nairobi, Kenya. Printed by ILCA, P.O. Box 5689, Addis Ababa, Ethiopia. Copyright © 1994 by the International Laboratory for Research on Animal Diseases. ISBN 92-9055-298-0 The correct citation for this book is Towards Increased Use of Trypanotolerance: Current Status of Research and Future Directions. Proceedings of a Workshop Organized by ILRAD and ILCA, ILRAD, Nairobi, Kenya, 26–29 April 1993, eds. G.J. Rowlands and A.J. Teale. Nairobi: The International Laboratory for Research on Animal Diseases/The International Livestock Centre for Africa, 1994. Contents Introduction Openingaddress A.R.Gray SIGNIFICANCEOFTRYPANOTOLERANCEAS A CONTROLOPTION Trypanotolerantlivestock,asustainableoptionforincreasing livestockproductionintsetse-affectedareas G.D.M.d’Ieteren BIOLOGYOFTRYPANOTOLERANCE Factorsaffectingestimationoftsetsechallenge andtheexpressionoftrypanotolerance S.G.A.Leak,G.D.M.d’IeterenandG.J.Rowlands Fieldresearchonmeasurementanduseoftrypanotolerance criteriatoenhancetrypanotolerantlivestockproductivity. 1.ILCA’sachievementsandfutureplans G.D.M.d’IeterenandJ.C.M.Trail Fieldresearchonmeasurementanduseoftrypanotolerance criteriatoenhancetrypanotolerantlivestockproductivity. 2.Recentresultsquantifyingtrypanotoleranceindicators J.C.M.Trail,N.WissocqandG.D.M.d’Ieteren GeneticimprovementofgrowthparametersinN’DamacattleinMali D.PlanchenaultandM.Traoré CharacterizationandmechanismsoftrypanotoleranceinBaoulécattle G.DuvalletandS.M.Touré Antibodyresponsestothesurface-exposedepitopesofthetrypanosome variablesurfaceglycoproteininN’DamaandBorancattle D.J.L.Williams,K.Taylor,B.Wilkie,B.GichukiandE.Authié CONTENTS iii Antibodyresponsestoinvarian tantigensofTrypanosomacongolense E.Authié,A.Boulangé,D.Muteti,K.TaylorandD.J.L.Williams CD5+ BlymphocytesincattleinfectedwithAfricantrypanosomiasis J.Naessens Comparativebonemarrowresponsesdurin gTrypanosoma congolenseinfectioninN’DamaandBorancattle A.G.Andrianarivo,P.Muiya,M.OpolloandL.L.Logan-Henfrey Markersformappingtrypanotolerancegenes S.J.KempandA.Teale TheOrmaBoran—tenyearsoffieldobservations R.B.Dolan,H.Alushula,L.Munga,M.Mutugi,C.Mwendia, G.Okech,P.D.Sayer,P.G.W.Stevenson,R.L.BakerandM.Magadi Variatio ninsusceptibilitytotsetse-bornetrypanosomiasis amongBosindicuscattlebreedsinEastAfrica E.K.Mwangi,P.Stevenson,G.GettinbyandM.Murray Variation sinsusceptibilitytotheeffects oftrypanosomiasisinEastAfricanzebucattle G.J.Rowlands,G.D.M.d’Ieteren,E.Authié,S.G.A.Leak, WoudyalewMulatuandS.M.Nagda ADOPTION,UTILIZATIONANDIMPACTOF TRYPANOTOLERANCE PromotionofN’Damastockbreedingandextensionactivities invillageherdsintheYanfolilaareaofMali M.Traoré,D.Planchenault,O.Kone,F.BertiandA.S.Berthe Theeconomicsoftrypanotolerantcattleproductioninregions oforiginan dareasofintroduction P.IttyandB.M.Swallow CattlebreedpreferencesandbreedingpracticesinsouthernNigeria B.M.SwallowandM.A.Jabbar SalvagingtheimageoftheN’Damabreed:productivityevidence fromvillageproductionsystemsinTheGambia K.Agyemang,D.A.LittleandR.H.Dwinger iv CONTENTS Ecological,socialandeconomicimpactsoftrypanotolerance: collaborativeresearchinCentralandWestAfrica R.S.Reid,J.J.Curry,B.M.Swallow,A.W.Mukhebi,B.D.PerryandJ.E.Ellis CONSERVATION,PRESERVATION,ENHANCEMENTANDPROPAGATION Characterization,conservationandutilizationofindigenous Africananima lgeneticresources—ILCA’sproposedprogram J.E.O.RegeandR.L.Baker Progressinmolecularandgeneticcharacterization ofcattlepopulations,withemphasisonAfricanbreeds A.J.Teale,P.Gwakisa,J.C.MaillardandS.J.Kemp Multiplicationofimprovedtrypanotolerantlivestock D.J.Clifford ProgrammeforConservationofDomesticAnimal Diversity:aFoodan dAgricultureOrganizationcontribution toconservinganima lgeneticresources R.T.WilsonandK.Hammond Breedingbiotechnologies D.Kennedy RECOMMENDATIONS APPENDIX:LISTOFPARTICIPANTS CONTENTS v Introduction The International Laboratory for Research on Animal Diseases (ILRAD) and the Interna- tional Livestock Centre for Africa (ILCA) are components of the Consultative Group for International Agricultural Research. They are the only CGIAR Centers focused entirely on aspects of livestock production. In the early 1970s, when the Centers were founded, it was apparent that disease was a major constraint on livestock productivity in sub-Saharan Africa. Today it is estimated that losses, both direct and indirect, are worth a total of $5 billion annually. Among the diseases, it is generally accepted that trypanosomiasis is the most important in terms of impact on livestock productivity, particularly in the wetter semi-arid, subhumid and phumid agroecological zones. In recognition of this, ILRAD and ILCA have, since their inception, maintained complementary research programs on aspects of trypanosomiasis, with emphasis on the tsetse-transmitted disease of cattle in Africa. Trypanosomiasis control relies on trypanocidal drugs, control of the vectors and farming of trypanotolerant livestock. Each of these options suffers shortcomings. Resistance in trypanosomes to the available trypanocides is a constant and, in some areas, increasing threat. Drugs are not always available and their purchase consumes valuable foreign exchange. Considerable advances have been made in recent years with the development of new insecticides and methods for their application, and with trap and target technology for vector control. Undoubtedly these approaches hold great promise. However, they require continuous commitment, and when control programs are relaxed the tsetse fly vectors are able to recolonize previously cleared areas very rapidly. In the case of trypanotolerant breeds of cattle, availability is limited and they account for only 17% of the total cattle population in the affected areas. Improvement and wider dissemination of trypanotolerant animals are needed if the genetic approach to control is to have a greater impact in the foreseeable future. Research at ILCA has been conducted on trypanotolerance since 1977. Research has also been conducted on the importance of trypanosomiasis relative to other diseases and on the efficacies of the different control options available, with emphasis on the use of trypanotolerant livestock. One of the major thrusts of this program has been the identifi- cation of trypanotolerance indicators and their use in genetic improvement of productivity and disease resistance in N’Dama cattle. This research has largely been conducted through the African Trypanotolerant Livestock Network (ATLN) and has involved a number of partnerships with national systems and regional laboratories. ILRAD has for the most part played a supporting role in the ATLN, which has included development and supply of a sensitive diagnostic test capable of revealing the cryptic infections which are often a feature of trypanotolerant livestock. In 1983, a number of cryopreserved N’Dama embryos were transported from The Gambia to Nairobi, and these formed the founder generation of a herd of N’Dama cattle maintained on the ILRAD site. The development of this resource has enabled scientists at INTRODUCTION vii ILRAD to undertake detailed studies of the responses to challenge with trypanosomes in trypanotolerant cattle, and to compare these with responses in trypanosusceptible Boran cattle with