Inst. of Advanced Studies, 
UN University, Tokyo
Bui Xuan Men, Brian Ogle and T.R. Preston. 1998.
 Studies on Duck Production in the Mekong Delta, Vietnam  
 In: Integrated Bio-Systems in Zero Emissions Applications.
Proceedings of the Internet Conference on Integrated Biosystems.
Eds: Eng-Leong Foo & Tarcisio Della Senta. 1998  http://www.ias.unu.edu/proceedings/icibs/men
 
About the Authors
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About the Authors
Mr. Bui Xuan Men, Faculty of Agric., Cantho Univerversity, Cantho, Vietnam.  
E-mail: bxmen@ctu.edu.vn 
Mr. Bui Xuan MEN is an expert on duck raising systems in S.Vietnam. He has conducted research on the use of duckweed to substitute supplemental protein in diets of ducks raised in smallholders , use of local ducks for insect pests and weed control in rice fields and thus reducing insecticides and herbicides applications. 
Dr. Brian Ogle, Dept of Animal Nutrition and Management, Swedish Univ. of Agric.Sci., Uppsala, Sweden. E-mail: brian.ogle@huv.slu.se 
He has a PhD in animal nutrition, with over 25 years experience in the tropics. Firstly at the Agricultural University in Tanzania in the early 1970's and then at the University of Botswana, Lesotho and Swailand between 1975-79 teaching tropical livestock systems and monogastric nutrition. He came to Sweden in 1983 after 2 years at the University of California, Davis, and since then have been the project leader of a number of SAREC (Swedish Agency for Research and Economic Cooperation in Developing Countries) financed University Research cooperation projects in East Africa and Vietnam, focussing on integrated smallholder livestock systems based on renewable natural resources since 1992. Dr. Ogle has also been the course director of an international M.Sc.programme ("Sustainable Tropical Livestock Systems") based in Vietnam and at the Swedish University of Agricultural Science; with students from Africa and SE Asia. He is currently the superviser of 3 Vietnamese PhDs investigating locally available feedstuffs for monogastrics. 
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 Dr. T.R. Preston. Finca Ecologica, Univ of Agric.& Forestry, Thuduc, Ho Chi Minh City, Vietnam. E-mail: tpreston@HCM.VNN.VN 
Dr. Thomas R. Preston was born in Cumbria, north-west England, and brought up on the family farm. He was educated at Newcastle University and gained his D.Sc. from work done at the Rowett Research Institute, Aberdeen. He has spent the last 32 years, living and working in tropical developing countries, beginning in Cuba, and including extensive experience in Mexico, Dominican Republic, Ethiopia, Colombia and most recently in Vietnam. He is known in Britain as the inventor of the intensive barley - beef production system in the 60s. However, during his time in Cuba, at the height of the American blockade, he realized that intensive beef production based on cereals was not feasible economically while from the ecological viewpoint, the tropics offered much greater production potential in indigenous crops such as sugar cane. He has since devoted his time to developing feeding systems using locally available resources not competitive with human needs. He is the principal promoter of the idea of the University of Tropical Agriculture Foundation and  the coordinator of the program. 
 
Abstract
Five experiments were carried out both on station and on small farms in the Mekong Delta, Vietnam to evaluate the use of duckweed as a replacement for soyabeans in broken rice based diets for growing ducks, and to determine the effects of feed supplementation of scavenging ducks.   

The two first experiments were carried out with crossbred common ducks on station, and with Muscovy ducks on a small farm. The ducks were fed broken rice diets, in which soyabeans were replaced partially or completely by fresh duckweed in the growing period. There were no significant differences in daily weight gains between the crossbred ducks fed the diet with 100% duckweed replacing soyabeans and the conventional diet. The gains were significantly higher (P<0.001) for the ducks fed 30 and 45% soyabeans replaced by duckweed. Feed conversion ratios (FCR) were significantly inferior in all diets with duckweed. There were no significant differences in the gains between female Muscovy ducks fed the diet with 56% and 100% duckweed replacing soyabeans and the conventional diet. However, the daily gains were significantly lower with 47% and complete replacement for the male Muscovy ducks. The FCRs tended to be inferior for the duckweed diets. There were no significant differences in carcass traits between treatments for the crossbred, and the female and male Muscovy ducks.   

Two experiments were conducted with improved common ducks and female Muscovy ducks at the Cantho University research station. The ducks were fed levels of 80 or 60 g/duck/day of broken rice and duckweed ad-libitum from 28 to 63 days of age for the common ducks and 28-70 days for the females. Daily gains were significantly lower with the restricted broken rice diets, except for the 80 g/day broken rice diet for common ducks. The FCRs were significantly improved in the restricted broken rice diets. Complete replacement by duckweed in the diet with 60 g/day broken rice had the lowest feed cost.   

An experiment was carried out using scavenging ducks on farms in the rural area. The ducks were given supplements consisting of a mixture of broken rice and dried fish meal, or broken rice and dried fish meal alone. These diets were fed to crossbred scavenging ducks from 28 to 70 days of age at night in the farmers' households. The liveweight gains were significantly higher for the fish meal and broken rice mixture than for the broken rice diets. However, the cost per kg gain for these diets were higher compared with no supplement.   

Key words: Crossbred ducks, Muscovy ducks, duckweed, soyabean, daily gain, intake, local resources.