Livestock Research for Rural Development 22 (4) 2010 Notes to Authors LRRD Newsletter

Citation of this paper

Effect of cassava hay supplementation to untreated rice straw and a mineral-urea block on growth rate of swamp buffaloes under small-holder conditions

K Souksamlane, P Ammaly and M Wanapat*

Livestock Research Center, National Agriculture and Forestry Research Institute,
Ministry of Agriculture and Forestry, Lao PDR
* Tropical Feed Resources Research and Development Center (TROFREC),
Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand


Eighteen male buffaloes 1.5 to 2 years of age and from 200 to 220 kg live weight were selected, one from each of 18 households. They were allocated equally to three groups (each group represented by 6 households). Each group of buffaloes grazed together in the day-time and were supplemented in the night-time according to the following treatments: Control: Rice straw; MUB: A mineral-urea block offered ad libitum plus rice straw; MUB-CH: MUB plus cassava hay at 0.5 kg/head/day plus rice straw.

Growth rates were improved 34% by supplementation with the mineral-urea block and by 250% when cassava hay was given together with the block.

Key words: Farmers, grazing, households, village


Live stock play an important role in rural livelihoods, especially as a major source of income for small-holder farmers; they also contribute to regional and national economies. They are found on over 90% of farms in Lao PDR. Buffaloes are especially important as they contribute to the sustainability of mixed crop-livestock farming systems. In 2003, the population of buffaloes in Lao PDR was 1.1 million (NAFRI, NAFES and NUOL 2005).  They are evenly distributed throughout the country and are generally associated with lowland rice production because of the need for draft power.

Buffaloes are generally fed on poor-quality roughages, which are also low in protein. (Chantalakkana 2001).  Rice straw is the most common roughage in Lao PDR, as it is available as the byproduct from crop cultivation. It is the main feed in the dry season when natural grasses are in short supply.

Supplementation with rumen “nutrients” and bypass protein is the recommended strategy for improving utilization of cereal straw in ruminant diets (Preston and Leng 2009). A block containing fermentable nitrogen (urea) and minerals helps to satisfy the nutritional needs of rumen micro-organisms (Leng 1990), while cassava foliage has been shown to be a good source of bypass protein (Ffoulkes and Preston 1978; Wanapat et al 1997; Keo Sath et al 2007).

The objective of the present study was to compare the above feeding strategy with the free grazing system as basal diets for young, growing swamp buffaloes.

Materials and methods


The experiment was conducted in small-holder farms in Namkeng village, Nhachaytong district, about 40 km from Vientiane City. The climate in this area is characterized by the two seasons: dry and wet. The wet season is from May to October. Annual rainfall is from 1400 to 1800 mm, with the peak occurring in the period July to August. The average minimum and maximum temperatures are about 15 and 32oC, respectively.

Experimental design

Eighteen male buffaloes 1.5 to 2 years of age and from 200 to 220 kg live weight were selected, one from each of 18 households. They were allocated equally to three groups (each group represented by 6 households). Each group of buffaloes grazed together in the day-time (Photo 1), and were supplemented in the night-time according to the following treatments:

Photo 1. Buffaloes grazing on the road sides

The experiment lasted 120 days after 15 days for adaptation to the treatments. The animals were vaccinated against Foot and mouth disease, de-wormed with Invermectin and injected with vitamins A, D3 and E before the commencement of the experiment.

Feed preparation

Rice straw (RS) was collected from local farmers around the village. Cassava was cultivated in areas close to the households. The foliage (comprising young stems, leaves and petioles) was harvested 3 months after planting and chopped into small piece prior to being sun-dried for 2 to 3 days (Photos 2 and 3). After drying, the cassava hay was stored in green nylon bags. It was fed at the rate of 0.5 kg/animal/day.

Photo 2. Sun-drying the cassava foliage Photo 3. Feeding the cassava foliage

 The mineral-urea block (Table 1) was offered ad libitum.

Table 1: Ingredients in the minerals-urea block #


 (% air-dry basis)

Rice bran








Bone meal








# Water was added in quantities required  to facilitate the mixing of the ingredients


The buffaloes were weighed before feeding in the morning at the beginning of the experiment and then every 30 days. Feeds offered and refusals were recorded daily and samples collected at random for analysis. Dry matter (DM), ash and crude protein (CP) were determined according to AOAC (1990).  NDF and ADF were analyzed according to the procedures of Van Soest et al (1991).

Statistical analysis

The experimental data were analyzed using the General Linear Model (GLM) of the Minitab software (Minitab 2000).  Sources of variation were treatments, household group, interaction treatment*household group and error.

Results and discussion

Chemical composition of feedstuffs

The ingredients used and their composition are shown in Table 2.

Table 2. Feedstuffs used in the experiment and their chemical composition



Rice straw

Cassava hay

Dry matter, %




As % in DM








  Crude protein












Feed intake and growth performance

Buffaloes in the control group ate more rice straw and more total DM than those supplemented with the mineral-urea block or the block together with cassava hay (Table 3). The cassava hay plus MUB group had higher total DM intakes than those supplemented only with MUB.

Growth rates were improved 34% by supplementation with the mineral-urea block and by 250% when cassava hay was given together with the block (Table 3; Figure 1).

Table 3. Effect of cassava hay, with or without mineral-urea block supplementation, on feed intake and live weight gain in swamp buffaloes



Supplemented groups






 DM intake, kg/day






Rice straw






Cassava hay


















Per 100 kg of BW






Live weight, kg


















Daily gain






a,b,c Values on the same row with different superscripts differ at P<0.05


Figure 1. Effect if supplementation on growth rates of buffaloes under smallholder farm conditions

The experiment was conducted in the rainy season so grazing was available. However, the advantages of applying the strategy of feeding the rumen (MUB) and the animal (cassava hay) are clearly demonstrated. The major impact of the cassava foliage on the growth rate of the buffaloes is in line with findings from similar trials with cattle fed cassava foliage (Ffoulkes and Preston 1978; Seng Mom et al 2001; Tran Quoc Viet and Dao Duc Kien 2005; Keo Sath et al 2007; Ho Thanh Tham et al 2007).



The authors are grateful to the Swedish International Development Agency (Sida), Department for Research Cooperation with Developing Countries (SAREC), through the MEKARN regional project for supporting this research fund. Thanks also to the National Agriculture and Forestry Research Institute (NAFRI) and the Livestock Research Center (LRC) for permission to use their research facilities. Research assistants and the farmers are thanked for their cooperation.


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Received 3 March 2009; Accepted 21 February 2010; Published 1 April 2010

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