Proceedings Buffalo Workshop December  2001

http://www.mekarn.org/procbuf/chin.htm

 

Potential of agro-byproducts as feed resources
for buffaloes in Vietnam
 

Bui Van Chinh and Le Viet Ly

National Institute of Animal Husbandry,
Hanoi, Vietnam

Introduction

Mechanization  of agriculture has increased quickly in Vietnam during the past 10 years, with draught power being provided by small agricultural machines,. However, the buffalo population has not decreased. There were 3 million buffaloes in 2000 compared to 2.85 million in 1990 and 2.6 millions in 1985. There are seven eco-agricultural zones suitable for buffalo raising in Vietnam, but climatic constraints are the 5-6 months dry season in the South and 4-5 months of winter season in the North. During these  times the productivity of buffaloes is decreased through lack of roughage and body weight is lost. The grazing land is limited, and the productivity of natural grasses is very low (6-8 tonnes /ha / year according to Nguyen Ngoc Ha 1994). Much of the grazing land is hilly, sloping land, and there is over grazing. However, in Vietnam the agro-byproducts are abundant such as: rice straw, maize stover, groundnut vines, sweet potato creepers, cassava tops, sugar cane leaves, pine apple tops, and pine apple waste.

 

Only a small part of these products is used as ruminant feed. The main part is left on the field and then burned or a little may be used as fuel (Bui Van Chinh and Le Viet Ly 2001). There are many studies in ruminants on agro-byproduct processing by application of ammonia and urea, with good results from  feeding trials in Vietnam in particular and other tropical and European countries, in general (Sundstol 1984; Preston and Leng 1987, Le Viet Ly and Bui Van Chinh 1994; Wanapath 1999). Although research has been done on the technology for treating rice straw by urea,  there are few data to demonstrate the potential of the agro-byproduct resources such as the ratio of rice straw and paddy rice (in dry matter). This  is recorded as 1: 1 by FAO, but the Vietnamese farmers are accustomed to harvest only two thirds of the straw, therefore in fact the ratio between rice straw and paddy rice tends to be lower than 1:1. There is even less research on determining the potential of other agro-byproducts  from crops such as maize, groundnut, sweet potato and cassava.  Therefore the objectives of the study were as follows:

• Determination of the chemical composition of agro-byproducts.

• Estimation of the quantity of the byproduct resources.

• Investigation of the use of the agro-byproducts for buffaloes on smallholder farms in Vietnam.
   

Materials and Methods

The quantity of the rice straw, ground nut vines, old maize stems, sugarcane leaves and cassava tops was estimated by selecting 5 points in the field with 25 square meters for each with 3-5  replications in Red River fields, and Northern mountainous  areas.

Methods for chemical composition analysis of the agro-byproducts were carried out by Vietnamese standard (TCVN-86) aileds nd AOAC (1980) methods. The total of agro-byproducts was estimated from the Vietnam statistical Yearbook (2000), and the results of the research.

The extent of using agro-byproducts for buffalo in the mountainous and hilly areas was assessed by participatory rural appraisal (PRA) methods (FAO).

 

Results and discussion

Nutritive value of the main agro-byproducts in Vietnam

Table 1. Chemical composition and nutritive values of the main agro-byproducts in Vietnam.
	DM	% on dry matter (DM) basis				ME
	(%)	CF	CP	NFE	TDN	(Kcal/kg DM)
Rice straw	90.8	34.3	5.1	42.8	45.9	1662
Old maize stems (winter crop)	35.5	30.2	8.4	54.4	54.7	1958
Sugarcane leaves	28.8	42.9	8.2	38.2	43.3	1578
Sweet potato creepers	20.0	24.5	11.0	47.0	59.5	2160
Groundnut vines	22.5	27.7	14.1	43.3	63.6	2289
Cassava tops	25.5	22.7	16.9	46.4	67.5	2549
DM: Dry matter, CF: Crude fibre, CP: Crude protein, NEF: nitrogen free extractives, TDN: Total digestible nutrients

 

The main constraints in rice straw, maize stems and sugar cane leaves are the low contents of crude protein and the high level of crude fibre (Table 1).

Investigation of the yield of the main agro-byproducts

Rice straw, old maize stems, ground nut vines, cassava leaves, sugarcane leaves were investigated in some provinces in North Vietnam. (Table 2). 

Table 2. Investigation of gross output of  some agro-byproducts
Byproducts	No of studies (years)	Total samples (m2)	Productivity (kg DM/ha)
Rice straw	2	1250	3490
Old maize stems (winter crop)	1	625	2970
Groundnut vines	2	2500	1780
Cassava tops	2	1250	1260
Sugarcane leaves	1	625	215

 

Estimation of the total gross out put of the agro-byproducts in Vietnam

 

The total gross output of agro-by-products such as sweet potato vines, and waste pineapple and vegetable by-products is estimated at nearly 1 million tonnes (in dry mater) (Le Viet Ly and Bui Van Chinh 1996). Therefore, the total quantity of the agro by-products that can be used as ruminant feed is over 29 million tonnes.

The use of agro- byproducts as buffalo feed

           

Buffaloes in the provinces of Tuyen Quang, Thai Nguyen, Lang Son and Hoa Binh are grazed on the pasture nearby the forest or reforested areas. The buffalo production is mainly to supply draught power and for reproduction and sale. In these areas the buffalo production is very important as part of the economic development strategy. The buffalo population is usually 1.5 to 2 times higher compared to cattle in the villages.  In the investigated areas, there is some advantage because of availability of grazing land, but in fact the farmers showed that green grasses are not enough for buffaloes because the grazing land is reduced by reforesting development. The lack of green fodder is serious during the winter season because grass does not grow or has died because of the cold weather (there are some days when the temperature is only 4 to 6^oC), and the lack of water. Therefore the farmers have to make use of the agro-byproduct resources as buffalo feeds the year around according to harvesting seasons (Table 5). 

Table 5. The availability and use of the main agro-byproducts at 4 locations.

Jan.

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Rice straw

+++

+++

++

++

+

+

++

++

+++

Maize stoves

++

+

+

+

+

+

++

Sugarcane leaves

+

+

+

+

Sweet potato creepers

++

+

+

+

+

+

+

++

++

Groundnut vines

+

+

+

+++: Byproduct is main component of the diet;  ++: Byproduct accounts for 20-30% of the diet  +: Byproduct is about 10-15% of the diet

           

Most farmers said that rice straw was the basic feed throughout year, except for June, July and August when there is enough green fodder. After harvesting of spring rice crop and winter crop, the straw is dried and stored in a dry and clean location to feed the buffaloes during the year. Almost no farmers applied the method of treatment for rice straw by urea. Yet research has shown that by use of urea-treated straw during the winter season, the straw intake of ruminants would be increased by 55 to 70% compared with untreated rice straw and cattle and buffaloes would not lose body weight during the winter season (Bui Van Chinh et al 1994; Bui Van Chinh and Le Viet Ly 2001; Wanapat 1999).

 

The other agro-byproducts are mainly used in  fresh form during harvesting times, therefore only a small part is used as animal feed and the main part is wasted on the field, because the harvesting time is limited to only 2 to 3 weeks. The groundnut vines can be made into silage and can be stored for 9 to 12 months and is a good animal feed resource during winter and dry seasons (Bui Van Chinh et al 1997). Farmers do not use the fresh cassava tops as cattle and buffalo feed because they believe the  toxic HCN is a problem, therefore it is usually wasted on the field. However, the treatment of the cassava leaves by ensiling decreases by 90% the HCN content. The green grasses were replaced by  50 to 100% by ensiled cassava tops in ruminant diets, with no loss of performance  (Bui Van Chinh et al 1997, 2001). The ensiled cassava tops and groundnut vines are easy to apply for smallholder farmer coonditions. Cassava hay has been a successful supplemental protein feed for buffalo in Thailand (Wanapat 1999).

 

Sweet potatoes are grown by farmers for harvesting the foliage as buffalo and pig feed with cutting interval from 30 to 40 days. Sweet potato foliage is rich in crude protein, carotene and soluble carbohydrate, therefore it is advantageous  for rumen fermentation, especially when the basal diet of buffaloes is rice straw.

Conclusion

Agro-byproducts in Vietnam are abundant with estimated availability of over 29 million tonnes DM per year. If better use could be made of these byproducts it would help to develop buffalo production in particular and ruminant production in general.

 

Vietnamese farmers have the habit to use agro-byproducts as buffalo and cattle feed, but in general only a small part is used as animal feed and the main part is left out on the field and then burned or used as fertilizer. Encouragement for farmers to make better use of the available agro-byproducts  is needed and would contribute to increased income.

 

References

Chinh B.V, Le Viet Ly, Preston T R,  N.H Tao and P.V. Thin 1994 Ammoniated rice straw or untreated straw supplemented with molasses-urea-blocks for growing cattle. Proceedings: “Sustainable livestock production on local feed resources”, p. 67-71, Agr. Pub. House.

 

Chinh B.V, Le Viet Ly and N.H Tao 1997 Storage and use of groundnut vines as animal feed. Proceeding regional workshop: “ Better use of locally available feed resources in sustainable livestock based agricultural systems in South East Asia, P. 44-47, Phnom Penh.

 

Chinh B.V.  and Le Viet Ly 2001 The use of some agro – byproducts for ruminants. Proceeding of National workshop on nutrition and feed for ruminants in Vietnam, P. 31-41, Hanoi.

 

Chinh B.V and N.V. Hai 2001. Study on the diet based on using of agro-byproducts for dairy cattle in winter season. Proceeding: The national annual scientific conference of the Ministry of Agriculture and Rural Development. P. 59-64.

 

Gohl B. 1993 Tropical feeds (in Vietnamese), Hanoi, P. 318-320).

 

NIAH 1995. Composition and nutritive values of animal feed in Vietnam, Hanoi.

 

Orskov E..R, 1993. Reality in rural development aid (with emphasis on livestock). Aberdeen.

Preston T.R and Leng A. R., 1987. Matching ruminant production systems with available resources in the tropics and subtropics. Penambul books, Armidale, NSW, Australia.

 

Statistical Yearbook of Vietnam, 2000. Statistical publishing house, Hanoi.

 

Wanapat, M.,1999. Feeding of ruminant in the tropics based on local feed resources. Thailand.

 

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