Introduction

Buffaloes play an important role in the agriculture of Vietnam, particularly in the North where the buffalo density is very high compared to other areas. Buffaloes provide the main source of draught power (about 95-96%) for cultivation in this area. Little research has been undertaken on working buffalos in this region, and little attention is given to the improvement of draught buffalos. The basal diets are grazing of low nutritive value and rice straw. These feeds are imbalanced in essential nutrients and it therefore likely that supplementation, especially with protein, will have beneficial results. Cassava root meal and cassava leaf meal are available in the mountainous areas of northern Vietnam, and the latter especially would be an appropriate supplement.

Results from two previous experiments showed that an increased level of cassava root meal and cassava leaf meal in the diet increased the body weight gain of growing-finishing young male swamp buffaloes. The objective of the experiment was to determine the effects of supplementation of cassava root meal and cassava leaf meal on the performance of working buffalo.

The hypothesis of the study is that supplementing cassava root meal and cassava leaf meal in the diet of working buffalo will improve feed intake, working capacity and body weight changes.
 

Materials and methods

Location

The experiment was carried out in Van Hoa village, Ha Tay province, where the mean annual air temperature is 22-23°C and mean relative humidity 85-86 %.

 Animals

Twelve adult male working buffaloes with average body weight of about 350 kg were used for the experiment. All experimental animals were grazed freely in the field and offered urea-treated rice straw at home during the night time. Clean water was available ad libitum during the duration of the experiment. 

Experimental design

The buffaloes were divided into 3 groups, with 4 in each group, balanced by body weight and age. Animals in the control group (CT) were not supplemented, while animals in group CRM were supplemented 1 kg cassava root meal daily, and animals in group CRLM were supplemented 0.5 kg cassava root meal plus 0.5 kg cassava leaf meal per day. The experiment was repeated for two months in each season (wet and dry). The buffaloes were supplemented for 1.5 months before ploughing continuously for two weeks to estimate the working capacity. When not working they grazed on natural pasture during the daytime and were given urea-treated rice straw in the evening (Table 1).

Parameters measured were feed intake, work done, selected physiological parameters and body weight changes.

Measurements

Feed intake

A total collection of fresh faeces was made every two weeks, and applying  assumed values of grass digestibility, daily feed intake was calculated.  

Work done

Speed of ploughing was measured by recording the distance ploughed in a given time (m/second), total working time, and total area (m²) in 120 minutes of continuous ploughing. 

Physiological parameters

Rectal temperature and heart rate were measured before and after working. Rectal temperature was measured by a thermometer in the rectum, heart rate by stethoscope, and recovery time was the time taken after stopping ploughing for body temperature and heart rate to return to the values recorded before working.

Body weight change

Body weight was determined using an electronic scale at the beginning of the experiment, before the working period, and at the end of the experiment. Time of weighing was in the morning before eating, drinking and working, . 

Statistical  analysis

The data were analyzed using the General Linear Model option in the ANOVA software of MINITAB program release 13.0. Sources of variation were supplements, season and error.    
 

Results and discussion 

Feed intake

For all experimental groups, estimated daily dry matter intakes were higher in the rainy season (Table 2) As the buffaloes were grazing freely, their main feed was natural grass, the availability of which depends on rainfall. In general natural grass is in surplus in the rainy season, but availability is limited in the dry season. Urea-treated rice straw was available freely at night, but the buffaloes consumed only small amounts in the wet season (0.5-0.6 kg/day), but much larger quantities in the dry season (about 6 kg/day).

In the wet season, total daily dry matter intakes were  8.7-9.3 kg, which were above maintenance requirements. However, in the dry season, the total daily DM intakes on all treatments were low, especially for the CT group (7.1 kg), which only just met maintenance requirements (Lawrence and Pearson 1999).

Effect of supplementation on working capacity

Speed and area ploughed in 120 minutes (Table 3) were significantly lower for the un-supplemented  group compared with the supplemented groups in both wet and dry seasons.

The speed and total area ploughed in 120 minutes was significantly lower in the dry season, because of limited feed resources, which resulted in poor body condition of the buffaloes compared to the wet season, when adequate feed was available. Another possible reason is that the soil was probably drier and harder in the dry season,  which would have made ploughing more difficult.      

The values for the area ploughed in the wet season were similar to the results from other studies. For example Sabrani  et al (1994) showed that swamp buffalo can plough 0.1 ha of rice field in 3.1 hours; Charan and Pakapun (2002) concluded that buffaloes can plough 0.05 to 0.08 acres (0.0202 to 0.0323 ha)  per hour. 

 The lower speed and area ploughed for the CT group can be explained by the lower daily DM intake. This is in line with results from studies on the effects of different feeding and nutrient intake levels on the working capacity of buffalo. A positive relationship between feeding level and working capacity has been confirmed by Wanapat et al (1994). Concerning the effect of supplementation on ploughing capacity of swamp buffaloes, Konanta et al (1986) reported that ploughing speed and area ploughed were significant higher for supplemented compared to non-supplemented buffaloes (53 m/minute and 0.48 ha/hour compared to 44 m/minute and 0.38 ha/hour, respectively). Wachirapakorn (1987) studied the effect of nutritional plane prior to working period on draught capacity of buffaloes, and also indicated that ploughing speed was 40 m/minute for those on a low nutrition plane compared to 47 m/minute for buffaloes on a high plane of nutrition.  

 Changes of some physiological parameters during ploughing, and recovery time

Rectal temperature increased by about 1^°C and heart rate increased by about 10 beats/minute as a result of ploughing(Table 4). There were no differences between groups and seasons in rectal temperature, heart rate and recovery time, although recovery time was slightly longer in the CT group. This is in agreement with the results of Wanapat et al (1988), who studied the effects of feeding on the draught capacity of buffalo, and showed that although rectal temperature increased by about 1^°C after ploughing,  there was no significant difference between treatment groups.  

 Effect of supplementation on changes in body weight

In the wet season, the body weight of all buffaloes did not change during the ploughing period. During the 4 first weeks of the study the buffaloes did no work and all animals gained weight; buffaloes in the CRM and CRLM groups gained significantly more weight than buffaloes in the control group (Table 5). In the 2 week working period the body weight of all buffaloes was almost unchanged, although animals in the control group lost around 2 kg, while buffaloes in the CRM and CRLM groups still gained some weight (4 and 3 kg, respectively). In the dry season, body condition of the buffaloes before the experiment was rather poor. During the 4 first weeks of the experiment, buffaloes in the supplemented groups gained weight, but buffaloes in the control group continued to lose weight. In the last 2 weeks (working period) buffaloes in the control group lost 8 kg body weight, while those in the CRM and CRLM groups managed to maintain their weight. These results are in line with those of Chaidet (1989, cited by Wanapat et al 1994), who studied the draught capacity and body weight change of buffaloes fed different rations over a working period of 20 days, and showed that buffaloes that were supplemented with concentrate still gained weight, while non-supplemented animals lost, or only maintained, weight during the ploughing period.

Conclusions

• Supplementation of working buffaloes with cassava root meal and cassava leaf meal increased dry matter intake, speed and area ploughed, and reduced body weight lost during the ploughing period.
• Supplementation had no effect on physiological parameters of working buffaloes.
• There appeared to be no advantage from feeding a combination of cassava leaf meal and cassava root meal compared with the latter alone.

Acknowledgements

The author is grateful for financial support from the SAREC-MEKARN project. Thanks are also due to Mr. Trinh Van Trung, Nguyen Cong Dinh and farmers in Van Hoa village for their help to conduct the experiment.
 

References

Charan Chantalakhana and Pakapun Skunmun 2002 Sustainable Smallholder Animal Systems in the Tropics. Kasetsart University Press, Bangkok, Thailand, 302p.

Konanta C, Limskul A and Treepun W 1984 A comparison of working ability between crossbred Murrah and native swamp buffaloes. Animal Husbandry Division, Department of Livestock Development. Annual report, Bangkok, Thailand. 

Lawrence P R and Pearson R A 1999. Feeding standards for cattle used for work. Centre for Tropical Veterinary Medicine, University of Edinburgh, 59p.

 Sabrani M, Kusuma Diwyanto and Winugroho M 1994 A critical review on buffalo research and development activities in Indonesia: past performance and future strategies. Proceedings 1^st Asian Buffalo Association Congress, January 17-21, 1994, Khon Kaen, Thailand, pp 78-89.           

 Wachirapakorn C 1987 The effects of nutrition on body condition prior to working in respect to voluntary feed intake, digestibility and physiological aspects of draft buffaloes. MSc Thesis, Khon Kaen University, Khon Kaen, Thailand.

 Wanapat M, Somart K, Wachirapakorn C, Uriyaponson S and Wattanachant C 1994 Recent advances in swamp buffalo nutrition and feeding. Proceedings 1^st Asian Buffalo Association Congress, January 17-21, 1994, Khon Kaen, Thailand, pp 155-187.

Wanapat M, Uriyaponson S, Chanthai S, Wanapat S, Wachirapakorn C and Thummasaeng K 1988 Improvement of nutritional status increase buffalo draft performance in the farming system. Khon Kaen University, Khon Kaen, Thailand.