Livestock Research for Rural Development

1997, Volume 9, Number 2

Abstracts of papers in LRRD, Volume 9, Number 2


An approach to the nutritional value for pigs of sweet potato vines (Ipomoea batatas (l.) lam)

P L Domínguez and J Ly

Instituto de Investigaciones Porcinas

Carretera del Guatao km 1, Punta Brava

La Habana, Cuba


Sun-dried sweet potato vine (SPV) meal contained in dry basis (g/kg): 234 crude fibre, 403 NDF, 328 ADF, 160 detergent lignin, 29.2 N, 216 ash and 158 kj/10 g DM gross energy. The effect of feeding SPV on nutrient digestibility was studied in either ileorectostomized or intact 45 kg liveweight pigs fed graded levels of SPV (0, 100 and 200 g/kg in the dry diet). SPV significantly decreased both ileal and faecal digestibility of most nutrients. Estimated ileal and faecal crude protein digestibility of SPV meal was 22.1 and 54.1% whereas in vitro ileal crude protein digestibility of SPV meal accounted for 42.2% thus indicating a rather low availability of crude protein in this biomass. The contribution of the large intestine to the digestion of diets ranged from 19.7 to 20.8% of energy disappearance in the entire digestive tract. Daily ileal and faecal output of short chain fatty acids and ammonia showed a trend to be proportional to the level of SPV meal in the diet. A low level of inclusion of SPV meal in the diet is suggested in order to avoid a negative effect on nutrient digestibility. Methods to improve digestion of this biomass could be encouraged.

Keywords: pigs, sweet potato vine, digestibility, fermentation


Promotion and utilization of polyethylene biodigester in smallhold farming systems in the Philippines

F A Moog, H F Avilla, E V Agpaoa,
F G Valenzuela and F C Concepcion

Research Division, Bureau of Animal Industry, Manila, Philippines



With the present energy and pollution problem in the Philippines, conversion of livestock wastes as source of energy and fertilizer, offers a great advantage for the livestock industry. A program that suits the need of backyard livestock raisers to abate the worsening problem of environmental pollution is now given high priority by the Bureau of Animal Industry (BAI) with the promotion of BAI Tubular Polyethylene Digester (BAI-TPED). A total of 99 biodigesters were installed nationwide of which eight (8) units are utilized for demonstration purposes in government stations or pilot barangays.

The technology is being promoted and proven with high degree of acceptance among farmers. Conduct of seminars along with field trips and study tours contributed much to make the technology popular and disseminated to the farmer clients. Several benefits can be obtained from TPED, in terms of source of renewable energy or fuel for farm household, fertilizer, sanitation and the cheapest means of minimizing pollution brought about by livestock wastes.

Key words: Biodigesters, renewabale energy, pollution, smallholders, livestock


Protein supplementation of traditional diets for crossbred pigs under village conditions in Central Vietnam

Nguyen Thi Loc, Brian Ogle and Thomas R Preston

College of Agriculture, Hue University, Vietnam


Availability and price of conventional protein supplements are major constraints to pig production in Vietnam. A survey in two villages in Central Vietnam showed that protein intake is very low in traditional diets (94 - 98 g/pig/day). A feeding trial was carried out in the same two villages to test effects of providing supplementary protein to the traditional diet. Fourteen weaner pigs (Mong Cai x Large White) were fed traditionally, and 12 similar pigs on similar basal diets were given supplements of groundnut cake and fish meal to provide an additional 100 g/day/pig of crude protein. The mean daily live weight gain of pigs under the traditional feeding system was low (202 and 230 g/day in each of the two villages) but was significantly increased to 363 and 366 g/day (P=0.001) by giving the protein supplement. The net economic benefit after deducting the cost of the protein supplement was VND 900/day equivalent to VND 135,000 for the 150 day fattening cycle.

Key words: Pigs, traditional diets, protein supplements


Cassava root silage for crossbred pigs under village conditions in Central Vietnam

Nguyen Thi Loc, R Brian Ogleand Thomas R Preston

College of Agriculture, Hue University, Vietnam


An on-farm trial in Binh Dien and Xuan Loc villages in Central Vietnam compared ensiling of cassava roots (ECR) (chipped by hand or ground by machine) with sun-dried cassava root meal (CRM) with supplements of "A" molasses at levels from zero to 20%. The HCN content of the ground whole cassava root after ensiling for 60 days was reduced from 109 ppm to 64 ppm, while ensiling the chipped root reduced HCN from 111 to 71 ppm. The optimum levels of "A" molasses replacing cassava root (ensiled or dried) in pig diets with protein supply kept constant at 200 g/day was in the range of 15 to 20% for live weight gain and economic purposes. Mean live weight gains were 465 g/pig/day for the cassava root meal diet and 453 g/pig /day for the ensiled cassava root diet each with 20% of "A" molasses. Feed costs/kg gain for the 20% molasses diet with dried and ensiled cassava root were 11% and 27% less than for corresponding diets without molasses.

Key words: Pigs, protein supplement, cassava root silage, "A" molasses, growth


Local feed resources and indigenous breeds:
fundamental issues in integrated farming systems

Lylian Rodríguez and T R Preston

Finca Ecologica, University of Tropical Agriculture, Thu Duc,

Ho Chi Minh City, Vietnam


The tropics present great opportunities for sustainable development thanks to the enormous cultural and biological riches of these regions. The rational exploitation of local feeds and local breeds of livestock will support much more sustainable production systems in the medium and long term. These have received insufficient attention in the past and have not been considered seriously because of the introduction of "exotic" systems based on high inputs, high technology and "breeds of high genetic merit". As a result, local breeds of pigs and cattle in many tropical countries have disappeared or their population is decreasing drastically.

On-farm research has shown that small scale farmers in Vietnam and in many parts of the tropical world continue to work with local breeds because of their good adaptation to the prevailing conditions. A project was carried out in two villages in a rainfed hilly region in Central Vietnam, involving the use of local Mong Cai pigs, local feeds supplemented with duckweed, and plastic biodigesters to produce energy for cooking and the nitrogen-rich effluent as fertilizer for the ponds in which the aquatic plants were grown. A study of the nutrition of Mong Cai, Large White and crossbred pigs showed that the indigenous breed would eat greater quantities of duckweed and use it more efficiently than the exotic breed. Local sows fed duckweed were also more prolific than exotic breeds on small farms with feed resources of low nutrient density.

The studies were carried out with a participatory approach which identified the importance of the local pigs and feed resources and the enthusiastic adoption of the biodigester technology and the production of duckweed based on the fertilized ponds. The priorities of the farmers were identified and a proposed intervention based on restricted milking of local cattle abandoned because it was considered too long term. Parallel studies in Cambodia led to the development of pig feeding based on juice from the sugar palm (Borassus flabillifer) supplemented with boiled soya bean seed and water spinach. Biodigesters were also integrated into the farming system.

The various studies demonstrate that the appropriate use of local feed resources and indigenous livestock breeds requires close integration between crops and livestock within the system. The excreta is recycled on the farm to produce energy and the effluent is used for fertilizer to produce protein supplements for the livestock.

Key words: Local feed resources, on farm research, recycling, biodigesters, genotype-environment interactions, indigenous knowledge, local breeds, integrated farming systems


The introduction of low-cost polyethylene tube biodigesters on small scale farms in Vietnam

Bui Xuan An, Thomas R Preston and Frands Dolberg

University of Agriculture and Forestry, Thu Duc, Ho Chi Minh City, Viet Nam




In order to evaluate polyethylene tubular digester development in Vietnam, interviews were carried out in ThuanAn district and at two extension centres. Data of design parameters, gas production, economic aspects, farmers' participation, technical problems and methodologies of biogas development were collected. The technology was appealing to the rural people because of its low cost, fast payback, simplicity and positive effect on pollution. The findings pointed to the importance of farmers' participation for technical feedback, plant maintenance, plant repair and teaching of other farmers. The dissemination of the technology needs the selection of real farmers with high fuel demands as demonstrators, the support of a credit system for the poor farmers and strengthening farmer-extension-scientist relations. Follow-up research should be focused on on-farm studies, particularly the use of the effluent (slurry).

Key words: Plastic tube biodigester, low cost, farmer impact, women, sustainable development.


Evaluation of protein quality in duckweed (Lemna spp.) using a duckling growth assay

Nguyen Duc Anh and T R Preston

University of Tropical Agriculture

Ho Chi Minh City, Vietnam



The trials were done during a one-month period, from 18 Dec 1996 to 18 Jan 1997 at the University of Tropical Agriculture, outside Ho Chi Minh City, Vietnam. Two trials using 5 and 10-day-old ducklings, were carried out using a method designed to evaluate quality of protein sources. A duckling growth assay is an attractive biological test because results are obtained within two weeks after giving the test protein. Energy sources free of protein were used to ensure that the growth response reflected the quality of the test protein..

The first trial aimed to test the method with a standard protein source which was soya bean meal given at levels of 10, 15, 20, 25 and 30% (approximately 7, 9, 11, 13 and 15% crude protein in feed dry matter) in the basal diet. A protein-free basal diet as the major energy source was provided by brown sugar and cassava root meal (50/50 mixture). In the second trial, the treatments were 100% replacement of the protein from soya bean meal for assaying the protein quality of fresh duckweed. There were five levels of a ratio (fresh weight basis) between duckweed and basal diet (brown sugar/cassava root meal = 50/50) of 1:1, 2:1, 3:1, 4:1 and 5:1 (approximately 3.3, 5.2, 6.8, 8.3 and 9.5% crude protein in feed dry matter). Growth rate of the ducks was positively correlated with the protein level (r=0.99 and 0.93 for the soya bean and duckweed, respectively).

It is concluded that: (i) growth rate of the duckling can be used to assay quality of protein resources; (ii) duckweed protein appears to have equivalent biological value to the protein of soya bean meal.

Key words: Duckling growth assay, duckweed, non-conventional protein sources, protein-free basal diet


Cassava hay: A new strategic feed for ruminants during the dry season

M Wanapat, O Pimpa, A Petlum and U Boontao

Department of Animal Science, Faculty of Agriculture

Khon Kaen University, Khon Kaen 40002, Thailand


Dry season feeding is critical in terms of both quantity and quality especially for productive ruminants such as dairy cattle. Cassava (Manihot esculenta, Crantz) a tuber crop can be grown as foliage in the dry season producing first cut yield after three months of 20,40 kg/ha (fresh) or 10,200 kg/ha (dried) and estimated combined yield of second and third cut of 40,820 kg/ha (fresh) or 20,400 kg/ha (dried) or 5,102 kg crude protein/ha. Cassava hay (CH) contained high level of crude protein (25%) and low levels of NDF and ADF. Voluntary intake of CH was 3.1% of live weight and the dry matter digestibility was 71%. Ruminal DM digestibility of CH was relatively high while protein ruminal degradability was low indicating it would be a good source of bypass protein.

Key words: Cassava, hay, feed, dry season, ruminant, dairy cattle.


Nitrogen digestion and metabolism in Mong Cai pigs fed sugar cane juice and different foliages as sources of protein

Du thanh Hang, Nguyen van Lai, Lylian Rodriguez and J Ly,

University of Tropical Agriculture, Thu Duc, Ho Chi Minh City


Growing Mong Cai pigs (10-14 kg live weight) were used in a 4*4 Latin square arrangement of 4 treatments, which were: ensiled cassava leaves, fresh foliage of cowpea, fresh duckweed, and silage made from a mixture of cassava and trichantera (Trichantera gigantea) leaves. These were given as the sole protein source in diets in which fresh sugar cane juice was the source of energy.

The intake of leaves, as percent of the total dry matter, ranged from 4% (cowpea) to 30% (ensiled cassava leaves). The digestibility of diet dry matter decreased with increase of leaves in the diet: from 96% (4% of leaves in diet dry matter) to 86% (30% of leaves in diet dry matter). On the basis of the regression of digestibility on percent leaves in diet dry matter it was estimated that the apparent dry matter digestibility of the leaves was on average 77%. N retention increased linearly as the proportion of leaves in the diet increased and was highest for ensiled cassava leaves.

Ensiled cassava leaves appeared to be the most palatable (highest N retention) of the foliages followed by duckweed. The fresh cowpea foliage was not liked by the Mong Cai pigs.

Key words: Nitrogen, Mong Cai pigs, ensiled cassava leaves, cowpea, duckweed, digestibility, nitrogen balance.


Effect of sugar cane juice on milk production of goats fed a basal diet of jackfruit (Artocarpus Heterophyllus) leaves

Nguyen Thi Hong Nhan and Thomas R Preston

University of Tropical Agriculture, Thu Duc, Ho Chi Minh City, Vietnam


The study was conducted with lactating goats (Bach Thao breed) to examine the feasibility of: (1) improving the utilization of leaves from the Jackfruit tree (Artocarpus heterophyllus); and (2) evaluating the use of sugar cane juice as an energy source to balance the protein in the leaves. Milking was once daily at 7.00 am, the kids being separated from their mothers from 12.00 am until 06.30 am the next day. The control diet consisted of ad libitum jackfruit leaves together with a multi-nutritional block (10% urea). The experimental diet was the same as the control plus a supplement of sugar cane juice of 1.5 kg/day. The first two weeks of the experiment were for adaptation to a standard diet (the control diet plus 500 g/day rice bran).The data obtained in the 3rd week on the standard diet were used as covariate to correct the milk yields during the experimental period in weeks 5-8.

The goats supplemented with sugar cane juice had a higher (P=0.063) average milk production (0.43 kg/day) in comparison with the controls (0.32 kg/day). Intake of fresh Jackfruit leaves was lower with cane juice supplement than on the control diet( P = 0.008). There was no effect of the sugar cane juice on rumen pH, ammonia or protozoal numbers.

It is concluded that a diet of sugar cane juice and leaves from the jackfruit tree can be recommended as a diet for lactating goats .

Key words : Lactation, goats, Jackfruit leaves , sugar cane juice