Le Hong Man
Vietnam Union of Poultry Enterprises
Fish and duck integration in research and development received considerable attention in Vietnam
and it has been proved effective. In each ha of swamp, pond or lake about 200–300 ducks can be
raised round the year. Subsequently, fish yield also has increased by about 30–40% in comparison
with ponds without ducks; it is due to the duck manure and waste feed which nourishes the ponds.
The paper briefly describes what has been achieved in Vietnam and experiences gained with this type of integration. Attention is paid to the water sanitation. However, this is not yet properly developed in Vietnam and needs to be further studied to extend to the appropriate areas.
In Vietnam, ducks have been kept under the traditional methods for long time, i.e. scavenging along the paddy fields. This method has proved its effectiveness in that it saves on the feed needed to provide the ducks.
After brooding period, ducks are raised in the paddy fields, small ducklings scavenge the snails, insects and crabs in the sloughed field and after that along the paddy rows. At night, farmers will give them some small supplementary feed. When harvesting seasons come, the adult ducks can feed themselves with the fallen paddy seed and no additional feed is given by the farmers. They will be slaughtered (at about 45–56 days old) when harvesting seasons finish. Experiences show that keeping duck in this way farmers have to give only about 1.5 kg paddy/ducks. However this method has its disadvantage. The duck rearing will have to depend upon paddy seasons and when improved technology for new rice varieties are introduced, duck can scavenge less feed in the fields.
In order to increase the economic efficiency of land use, conserve the nutrient resources and increase the income of producers, attentions have been paid to the integration of duck-fish-rice. Research had been done since 1970 for a duck-fish integration system. During this time, Phap Van duck-fish integration farm was established. Duck houses were built above the pond using cheap materials like bamboos and palm leaves. The duck scavenged snails and fishings in the pond and were also given supplementary feed. The waste feed and duck manure fell to the pond and thus became the feed source for fish. The results of this integration was quite encouraging. But in 1972 during the war research in this area was given up.
However, now in Vietnam, there are still some places where fish-duck integration is being done, e.g. Dai Xuyen Duck Breeding Centre, Hanamninh province; Cam Binh duck enterprise, Hai Hung province, Vinh Long and Tu Binh duck farms in the south. This integration is also being done by private producers, in household units in the villages and by members of VACVINA Association (This association encourages integrated production system, i.e. Gardening - Fish rearing - Livestock Production). Results obtained so far had been encouraging.
INTEGRATED PRODUCTION SYSTEM IN VIETNAM
The example of duck-fish-rice integration can be clearly seen in Cam Binh duck farm (under Union of Poultry Enterprises).
Local and overseas researches have shown that duck manure is a rich protein source. About 30– 35% dry feed consumed by ducks are usually undigested and excreted in manure. On average, every year each duck may excrete nearly 30 kg of manure. In the integration system, 70–80% of this source has been used to nourish the pond water and provide nutrition to the fish.
In Cam Binh duck farm, duck houses are built near the pond/lake border and in that pond, they keep various kind of fish like carps, salmon (a kind of carp), roach, tilapia etc. In the night, ducks are kept in the houses till about 8 a.m. (laying ducks will lay eggs in the houses before leaving for feed). During daylight, ducks scavenge food in the pond, they feed on snails, crab, algae, plankton, fishlings and other food available in the water. They are also provided with certain ration of mixed feed from automatic feeders scattered on the border of the ponds. Duck manure excreted together with the waste feed, which is cleaned and drained into the pond help the aquaculture, plankton, microbacteria and microbial grow quickly. These in turn become feed for either duck or fish. They have recorded that this system helps to save a part of supplementary feed (30–40%) and at the same time improve the environmental conditions of the fishes. The most desirable area in lakes/pond for integration system is 30/50 ha. The density of ducks raised depends on the water streaming and the cleanliness of the water. Generally, we can keep about 200–300 ducks/ha. After 2–3 years, the ponds/lake may become full of mud and the duck/fish yield start to reduce. Then ponds should be emptied to clear out the mud/sludge, repair the border and improve the sanitary conditions. The sludge can be used as organic fertilizer for the gardens or paddy rice. This has helped in increasing the paddy yields by 50–80%. After that, duckfish integration can be started again.
Another reason for the duck-fish integration is the benefits received from sales of fish. This is a substantial profit, even more than profits gained in duck production. In duck manure, there are substantial amount of nutrients: 72–79% nitrogen, 61– 87% phosphorus and 82–92% potassium (P. Edwards, Asian Technical Institute). This is the nutritive source for the development of aquaculture, phytoplankton, microbacteria, chaos and plankton, which are protein rich natural food for fish. The duck manure can help to reduce 20–25% fish feed. The most suitable type of fish for duckfish integration ponds are carps (Chinese and Indian carps), grass salmon, roach, Tilapia mosambica, Nile tilapia and other species of Oreochromus. In order to take advantage of all nutrients in the pond, they often choose different kinds of fish living in various water layer (above, middle and bottom). Fish yield from ponds with duck rearing is 30–40% higher than from ponds without ducks. However, in this integrated system there is still the problem of duck health care. Because while scavenging, ducks may eat the insects which are carriers of diseases. Research is now being done in Vietnam on these disease aspects.
POTENTIAL FOR FURTHER DEVELOPMENT
Vietnam has great potential for the development of an integrated production system as it has many swamps, lakes, ponds and duck production technology is now well developed in the country. Vietnam duck breeds particularly the local and local crossed with exotic ones well capable of scavenging either in paddy fields or ponds. This type of production system requires less investment as farmers need only to invest capital in purchasing ducklings and a sum for feed. Feed given to duck are the cheap carbohydrate rich sources like corns, rice polish, cassava starch, sweet potatoes and other kitchen waste. Meanwhile, they can get benefits both from ducks and fish, especially fish, as these almost do not need supplementary feed and still give high yield. The system also helps to improve the environmental condition and soil quality for paddy and other crop cultivation. Much more research must be done to study all aspects of the livestock-paddy-fish integration so that in future it becomes a popular method of production both in the state and private sector.
Fish-duck integration has initially enhanced the economic efficiency of animal production in Vietnam. However, it can further develop when Ministry of Agriculture is closely linked with the Ministry of Fisheries. An extensive survey should be undertaken in the whole country to determine the appropriate areas for such integrations.