Livestock Research for Rural Development 11 (3) 1999

Citation of this paper

Rumen environment and feed degradability in swamp buffaloes fed different supplements


Nguyen Van Thu and T R Preston*

College of Agriculture, Cantho University, Vietnam
nvthu@ctu.edu.vn
* University of  Tropical Agriculture Foundation, Phnom Penh, Cambodia 
trpreston@email.com

Abstract

Two experiments of Latin square design were carried out to investigate the effect of different supplements on the rumen environment and rumen degradability of local feeds in swamp buffaloes fitted with rumen fistulas. In Experiment 1 the four diets were: untreated rice straw ad libitum (R); 3.5 kg/day urea-treated rice straw plus untreated rice straw ad libitum  (RUTS);  untreated rice straw ad libitum and 450 g/day of a urea-molasses cake (RUMC);  untreated rice straw ad libitum and 2 kg/day of fresh leaves of  Sesbania grandiflora (RSES).  In Experiment 2, the diets were: rice straw ad libitum supplemented with natural grass (0.25%  animal live weight, DM basis) (RG); rice straw ad libitum supplemented with grass (0.25% animal live weight based on DM basis) and 700 g/day urea-molasses cake (RGUMC); natural grass ad libitum (G);   and natural grass ad libitum and 700 g/day urea-molasses cake (GUMC). The adaptation period of the animals for each diet was ten days, then the measurements were taken in the four consecutive days.

In experiment 1, rumen N-NH3 concentration, bacteria and protozoa populations, and feed dry matter intake, were significantly higher on the combination of Sesbania grandiflora  leaves and untreated rice straw than for all other treatments.  In experiment 2,  supplementation of a combination of rice straw and grass with the urea-molasses cake led to increases in rumen ammonia, in protozoal and bacterial populations and in feed intake.  The buffaloes lost weight on the basal diet  and gained weight with the UMC supplementation (P=0.07).  These effects were less pronounced when the basal diet was only grass. There were no apparent effects on the rate of rumen degradation of  rice straw and water hyacinth when rice straw was supplemented with grass or a urea-molasses cake.

Key words: Swamp buffaloes, urea-molasses cake, rice straw, grasses, Sesbania grandiflora, rumen environment, rumen degradation.


Introduction

Swamp buffaloes have played a very important role in providing draught power and beef for people in the Mekong delta of Vietnam. Farmers have benefited much from swamp buffalo production, but there are few studies on how to improve their performance and the profit for the farmers due to the lack of research resources. Traditional feeding systems, based on extensive grazing and use of fibrous crop residues without supplementation, have dominated management systems and been the cause of slow growth rates, poor working performance and ill-health in the dry and working season.  

Supplementing the buffaloes with a urea-molasses cake  (UMC), which includes urea, molasses, rice bran, coconut meal, salt and minerals, improved working capacity, growth rate and milk yield (Nguyen Van Thu et al 1996). The soft cake was easy to make and to transport.  Foliage from forage trees, especially leguminous species, was proposed by Preston and Murgueitio (1992) as an inexpensive way of providing supplementary protein to complement the nutrients provided by the urea-molasses cake or even as a complete replacement in situations where both molasses and urea were not easily obtained. Many tree species grow in the Mekong delta and while these have been studied as supplements, and even as complete feeds, for goats (Nguyen Thi Hong Nhan 1998) there has been no comparable work with buffaloes.

 The aim of this study was to obtain some preliminary regarding the possible role of tree foliages as supplements for swamp buffaloes fed basal diets of rice straw.


Materials and methods

Two experiments with Latin square arrangement of four treatments and periods of 14 days were carried with four swamp buffaloes fitted with rumen fistulas. These were 14 to 16 months of age with average liveweight of 184 ▒ 7.4 and 200 ▒ 17 kg, in Experiments 1 and 2, respectively.  The diets were: (In Experiment 1) rice straw ad libitum (R); rice straw ad libitum and 3.5 kg/day of urea-treated rice straw (RUTS); rice straw ad libitum and 450g/day of a  urea-molasses cake (RUMC); rice straw ad libitum and 2 kg/day of fresh leaves of  Sesbania grandiflora (RSES); and in Experiment 2, rice straw ad libitum and natural grass (0.25% animal liveweight based on DM basis) (RG);  rice straw ad libitum, natural grass (0.25% animal live weight based on DM basis) and 700g/day urea-molasses cake (RGUMC);  natural grass ad libitum (G) and natural grass ad libitum and 700g/day of a  urea-molasses cake (GUMC). The UMC contained (%): "B" molasses 37.9, urea 7.6, coconut oil meal 7.5, rice bran 39.4, bone meal 3.8, salt 3.8, and trace minerals 0.15. Its chemical composition (%) based on DM basis was DM 78.0, N*6.25 33.5, crude fibre 7.60, ether extract 9.0 and ash 11.5. The experiments were carried out at the experimental farm of Cantho University of Vietnam in 1997. The adaptation period of each animal for each diet was ten days. Measurements were taken in the four consecutive days. 

The effects of the diets on the rumen environment were studied by incubating standard feed samples in the rumen of each animal according to the procedure of ěrskov et al (1980).  The standard feeds were: rice straw and leaves of water hyacinth (Eichornia crassipes) collected  in the acid-sulfate soil area of Hoa An village, Cantho province.   In both experiments, the rice straw fed to the buffaloes was bought from villages around Cantho city where the soil is rich and not acid (pH >6.0). By contrast, the feed samples for rumen incubation were collected from the Acid-Sulphate Soil Research Station in Hoa An village (pH from 2.0 to 4.0), some 40 km from Cantho city. 

The standard feeds were dried and cut into 2-3mm length before placing them in nylon bags (pore size 50 Á) which were then inserted in the rumen.  The incubation times were: 6, 12, 24, 48, 72 and 96 hours with triplicate samples for each time.  Observed values for losses of substrate  were fitted to the  model DMD= a + b (1- e-ct ) following ěrskov and Mc Donald (1979), where DMD is the degradability after time "t", " a" is the intercept of the degradation curve at time zero, " b" is the fraction which degrades with time at a rate constant " c" and " a+b" represents potential degradability or the fraction that will be degraded in the rumen given sufficient time. Samples of rumen contents were collected at 6.00 am before the animal had access to the feeds. pH was measured by a pH meter. N-NH3 was analyzed by the Micro-Kjeldahl method. The preparation of rumen samples for counting of protozoa and bacteria was according to the procedure outlined by .  Protozoa were counted in a 0.2mm deep chamber under [x100]  magnification (Navas et al 1992). Bacteria were counted in a Neubauer chamber under [x1200] magnification (Warner 1962a). Feeds and refusals were  collected daily and pooled weekly for analysis of DM.  Feed samples for placing in the rumen were analyzed for dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL) and ash following procedures of AOAC (1990) and Goering and Van Soest (1970). The animals were weighed on two consecutive days at the end of each period. to prepare for a rumen incubation. 

The data were subjected to an analysis of variances (ANOVA) by using the general linear model (GLM) of Minitab Reference Software (Release 11, 1996). When the "F" test was significant, the least significant difference test was used to test differences between means following the procedure of Mead et al (1996).


Results and discussion

The rice straw produced from the acid soil area had a higher lignin content but less ash than that produced from the normal soil (Table 1). Reduced availability of calcium and phosphorus in acid soils have been reported by Ellis and Mellor  (1995) which could explain  the low ash content of the rice straw (8.1%) grown on the acid-sulphate soil.  The cell wall fractions differed markedly between the Sesbania leaves compared with the straw and natural grass. Concentrations of NDF, ADF, cellulose and hemi-cellulose in Sesbania leaves were less than half those in the straw and the grass.  By contrast the lignin in Sesbania leaves was high (7.3%) and in the same range as for the straw and the grass. A similar value for lignin (8.1%) in Sesbania leaves was reported by Norton (1994) who also observed  low values for NDF (24.4 to 37.1%). The composition of the water hyacinth was similar to that of the grass.

Table 1. Chemical composition (%) of  feeds given to the buffaloes and incubated in the rumen (dry matter basis).
OM CP NDF ADF Lignin Cellulose Hemi-
cellulose
Ash
Feeds offered
Rice straw  85.4 3.94 79.0 46.9 6.55 40.4 32.1 14.6
Urea-treated straw  88.1 12.2 79.0 48.9 7.52 39.5 30.1 11.9
Natural grass  89.8 9.7 69.9 38.0 5.54 32.5 31.9 10.2
Sesbania  92.1 33.8 35.4 18.7 7.31 11.0 16.7 7.93
Feeds incubated
Eichornia crassipes 85.7 11.4 67.3 34.1 4.79 29.3 33.2 14.2
Rice straw  91.9 6.14 77.5 47.3 7.21 40.1 30.2 8.10

In experiment 1, rumen N-NH3 concentration, bacteria and protozoa populations, and feed dry matter intake were significantly higher on the combination of Sesbania grandiflora  leaves and untreated rice straw than for all other treatments (Table 2).  Sesbania grandiflora foliage was shown to have a high nutritive value when given as  the sole feed to growing goats  (Nguyen Thi Hong Nhan 1998). Bonsi et al (1995) also reported that it supported higher feed intake of a tef straw diet than did Leucaena leucocephala.

Table 2. Rumen pH, ammonia-N and protozoal and bacterial populations in the rumen fluid of swamp buffaloes fed rice straw alone (R), "R" plus urea-treated rice straw (RUTS), "R" supplemented with a urea-molasses cake (RUMC) or "R" supplemented with leaves of Sesbania grandiflora (RSES) (Experiment 1)
R RUTS RUMC RSES SE / P
pH 7.32a 7.13b 7.01c 7.17b 0.06/0.004
N- NH3 (mg/100ml) 5.83a 8.16b 8.29c 9.72d 0.61/0.001
Bacteria (108/ml) 10.5a 12.3a 14.1c 15.2d 0.46/0.001
Protozoa (105/ml) 3.13a 3.36b 3.51c 3.70d 0.09/0.001
Feed  intake 
(g DM/kg W0.75/day)
68.5a 71.9b 76.6c 80.1d 1.77/0.001
Means with different letters within the same rows are significantly different at 5% level

In experiment 2 (Table 3),  supplementation of a combination of rice straw and grass with the urea-molasses cake led to increases in rumen ammonia, in protozoal and bacterial populations and in feed intake.  The buffaloes lost weight on the basal diet  and gained weight with the UMC supplementation (P=0.07).  These effects were less pronounced when the basal diet was only grass. The improvement in rumen parameters (Tables  2 and 3) and in liveweight change (Table 4) from supplementing the rice straw with a urea-molasses cake are in line with reports from many workers concerning the efficacy of this technology  (see review by Chenost and Kayouli 1997).  

Table 3. Mean values for  pH,  N-NH3, protozoal and bacterial populations in rumen fluid from swamp buffaloes fed rice straw and grass (RG), rice straw, grass and urea-molasses cake  (RGUMC), grass (G) and grass and urea-molasses cake (GUMC) (Experiment 2)
RG RGUMC G GUMC SE / P
pH 7.16a 7.04b 7.06b 7.19a 0.033/0.009
N- NH3 (mg/100ml) 6.35 a 9.59b 12.9c 18.0d 0.72/0.001
Bacteria (108/ml) 11.8a 14.4b 17.7c 18.6c 0.40/0.001
Protozoa (x105/ml) 3.56a 4.02b 4.09b 4.45c 0.03/0.003
Feed intake 
(gDM/kgW0.75/day)
66.1a 78.2cd 74.0bc 72.5bc 2.01/0.002
Live weight change (kg) -8.37 8.75 3.75 7.31 5.25/0.073
Means with different letters within the same rows are significantly different at 5% level

There were no apparent effects on the rate of rumen degradation of  rice straw and water hyacinth when rice straw was supplemented with grass or a urea-molasses cake (Tables 4 and 5). This is contrary to many reports in the literature of positive effects on rumen degradability of fibrous substrates from addition of these supplements to fibrous crop residues (eg: addition of African Star grass to a sisal pulp diet fed to sheep [Gutierrez and Elliott 1984], and of  molasses-urea blocks as supplement to rice straw [Wanapat et al 1991; Bui Xuan An et al 1992a,b]).

Table 4. Relative DM degradability (%) of rice straw in rumen of swamp buffaloes fed with different diets in experiment 2. (RG: rice straw and grass;  RGUMC: rice straw, grass and urea-molasses cake;  G: Grass; GUMCgrass and urea-molasses cake)
RG RGUMC G GUMC SE / P
Dry matter loss, %
0 h (washing loss)

4.37 0.18

6 h 10.5 9.40 9.45 9.23 0.38/0.063
12 h 13.0 14.8 15.6 15.2 1.07/0.189
24 h 22.4 23.4 23.8 21.2 3.09/0.838
48 h 40.4 36.8 38.5 37.5 2.76/0.606
72 h 46.9 46.2 47.6 48.6 1.41/0.54
96 h 54.4 53.4 51.8 55.2 1.40/0.195
Constants from the  model: DMD= a + b (1- e-ct )
a+b 67.0 65.1 59.2 76.9
"c" 0.015 0.014 0.017 0.012
R2 0.99 0.99 0.99 0.99
SE 1.82 0.23 0.77 1.15

 

Table 5. Relative DM degradability (%) of Eichornia crassipes  in rumen of swamp buffaloes fed with different diets in experiment 2. (RG: rice straw and grass;  RGUMC: rice straw, grass and urea-molasses cake;  G: Grass; GUMCgrass and urea-molasses cake)
RG RGUMC G GUMC SE / P

Dry matter loss, %

0 h (washing loss)

18.10.26

6 h 23.7 23.9 24.9 25.8 1.29/0.443
12 h 26.5 28.6 32.3 32.1 1.07/0.004
24 h 33.0 34.8 38.6 37.8 3.08/0.323
48 h 47.9 49.2 54.3 54.8 3.86/0.275
72 h 54.6 54.7 58.7 62.5 3.43/0.166
96 h 60.6 62.8 65.9 66.5 2.24/0.120
Constants from the model:  DMD= a + b (1- e-ct )
a+b 76.4 75.7 71.6 75.3
"c" 0.014 0.015 0.021 0.020
R2 0.99 0.99 0.99 0.99


Conclusions

Supplements of urea-molasses cake and leaves of  Sesbania grandiflora to a basal diet of rice straw brought about improvements in the  rumen environment and the feed intake of swamp buffaloes. However, under the conditions of this study there appeared to be no improvement in feed dry matter degradability by supplementation of the rice straw with either grass or the urea-molasses cake. 


Acknowledgements

This work was partly supported by a grant (No: B/2296-1) to the senior author from the International Foundation for Science.   The authors are indebted to the Department of Animal Husbandry and Veterinary  Medicine  of the Faculty of Agriculture, Cantho University for access to the facilities for carrying out the experiments. 


References

Association of Official Agricultural Chemists 1990 Official Methods of Analysis (15th edition). Washington DC,  Volume 1:69-90.

Bonsi  M L K, Osuji P O and Tuah  A K  1995  The effect of supplementing teff straw with different levels of leuceana or sesbania leaves on the degradabilities of teff straw, sesbania, leuceana, tagasaste and vernonia and on certain rumen and blood metabolites in Ethiopian Menz sheep. Animal Feed Science Technology 52: 101-129.

Bui Xuan An, Luu Trong Hieu, Nguyen Duong Khang and Preston T R 1992a Effect of position in the tree and pretreatment of Acacia mangium leaves on rumen dry matter and nitrogen degradabilities. Livestock Research for Rural Development (4) 2: http://www.cipav.org.co/lrrd/lrrd4/2/viet1.htm

Bui Xuan An, Ngo Van Man and Luu Trong Hieu 1992b Molasses-urea block (MUB) and Acacia mangium as supplements for crossbred heifers fed poor quality forages. Livestock Research for Rural Development (4) 2: http://www.cipav.org.co/lrrd/lrrd4/2/viet2.htm

Chenost M and Kayouli C 1997  Roughage utilization in warm climates. FAO Animal Production and Health Paper 135:1-226

Ellis S and  Mellor  A 1995  Soil constituents and properties. In Soils and environment. First publisher. 11 New Fetter Lane, London EC4P 4EE. 1995:50-53.

Goering  H  K  and Van Soest P J 1970 Forage Fiber Analysis (Apparatus, Reagents and some applications).USDA Agricultural Handbook. No.379, National Academic, Washington DC, pp. 1-19.

Gutierrez E and Elliott R 1984  Interaccion digestiva de la pulpa de henequen (Agave fourcroydes) y el pasto Estrella de Africa (Cynodon  plectostachyus) Alternativas y valor nutritivo de algunos recursos alimenticios destinados a produccion anima.   Informe Provisional No 16 Fundacion Internacional para la Ciencia: Stockholm  

Mead M, Curnow  R N  and Hasted  A M 1996 A simple experiment. In Statistical Methods in Agriculture and Experimental Biology. Second edition. 1996: 53.

Minitab 1996 GLM. In Minitab Reference Manual, Release 11. 1996: 3-41 - 3-56.

Navas A, Laredo M X, Cuesta A, Anzola H and Leon J C 1992 Evaluation of Enterobolium circlocarpum as dietary alternative to eliminate protozoa from the rumen. Livestock Research for Rural Development. (4), 1: 55-63.

Nguyen Thi Hong Nhan 1998  Effect of Sesbania grandiflora, Leucaena leucocephala, Hibiscus rosa-sinensis and Ceiba pentadra on intake,  digestion and rumen environment of growing goats. Livestock Research for Rural Development (10) 3: http://www.cipav.org.co/lrrd/lrrd10/3/nhan1.htm

Norton BW 1994 Tree legumes as dietary supplements for ruminants. Forage tree legumes in tropical agriculture. (Editors: Ross C. Gutteridge and H Max Shelton). CAB International. pp 178-201.

ěrskov E R, Hovell F D De  B and Mould  F 1980  The use of nylon bag technique for the evaluation of feedstuffs. Tropical Animal Production 5: 195-213.

ěrskov  E R and McDonald I  1979  The estimation of protein digestibility in the rumen from incubation measurements weighted according to rate of passage.  Journal of Agricultural Science Cambridge 92: 499-503.

Preston T R and Murgueitio E 1992  Implications of the energy and environmental crisis. Sustainable production systems. In: Strategy for sustainable livestock production in the tropics. CONDRIT. Ltd, Cali, Colombia. pp 20-27, 49-76.

Nguyen Van Thu, Pearson R A  and Preston  T R  1996  Effect of work and supplementation on performance of lactating buffaloes in Vietnam. In Proceedings of the 2nd Asian Buffalo Congress held in Philippines in Oct. 9-12, 1996: 104-116.

Wanapat  M,  Sommart K,  Ajsuk  P,  Wachirapakorn  C and  Toburan  W 1991 Effect of high quality feed block supplementation on intake, rumen fermentation characteristics in ruminants fed rice straw based diets.  Presented at the Regional workshop Making better use of local feed resources, Nov. 25-30, 1991, Hanoi, Vietnam.

Warner  A C  I. 1962  Enumeration of rumen micro-organisms. Journal of  General Microbiology.  28: 119-128.

Received 10 June 1999

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