Livestock Research for Rural Development 15 (6) 2003

Citation of this paper

Evaluation of some unconventional trees/plants as ruminant feeds in Central Vietnam

     Nguyen Xuan Ba and Le Duc Ngoan

Hue University of Agriculture and Forestry
nthanhhuong@dng.vnn.vn

Abstract

This investigation was aimed at evaluating foliage production and nutritive value of Muntingia calabuara,  Hibiscus rosa sinensis L, Mulberry (Morus alba) and Trichanthera gigantea based on chemical composition, rumen degradability and gas production. The trees were planted from stem cuttings at spacing of  0.2*0.5m for Mulberry and Trichanthera,  0.2*1.0m for Hibiscus and 1*1 for  Muntingia calabuara, which was planted from seedlings. The plot size was 25m for each of the trees.

The fresh biomass production  (average of the first 3 harvests at 10 week intervals) was 13.7, 8.1, 8.9 and 19.6 tonnes/ha for Hibiscus rosa sinensis L, two local varieties of Morus alba and Trichanthera gigantea, respectively. Muntingia calabuara  did not re-grow after the first harvest.   Rumen degradability of dry matter as well as gas production was higher in leaves and foliage of Morus alba and Hibiscus rosa sinensis L. than the others. Dry matter loss (in sacco) at 48h or gas production at 48h were better predictors of nutritive value than the coefficients of the fitted curve [P = a + b (1 - e -ct)].

In general, Morus alba, Hibiscus rosa sinensis L and Trichanthera gigantea trees seem to be promising fodder species especially in the dry season in central Vietnam. 

Key words: Gas production, Hibiscus rosa sinensis L, Morus alba, Muntingia calabuara,  rumen degradability, Trichanthera gigantea
 

Introduction

In central Vietnam, the population of ruminants occupy around 45% of the total live stock in the whole country. Because of harsh conditions (high temperature, low rainfall in the dry season), shortage of animal feed is a big problem for livestock development, particularly for grazing cattle. The main feed supplement for animals during the dry season is rice and maize straws and various crop residues. Quantity and quality of feed is usually limited, particularly the protein content. This is reflected in poor animal performance.

In recent years, there have been many studies on the of tree foliages as supplements for live stock (Leng 1997). In central Vietnam, there are some indigenous trees that can be used as forages. Among these are:

The research described in this paper was aimed at the evaluation of the agronomic characteristics and the nutritive value of the above trees as ruminant feeds.

 

Materials and methods

The experiment was started in September, 2001 in the Hue University of Agriculture and Forestry experimental farm in Hue City. The climate is tropical monsoon with a yearly rainfall around 3415cm, most of which occurs from August to January. The temperature range is 21 to 29 C. Air humidity varies in the range 79 to 91%. The soil is sandy loam with the pH around 5.5 in the topsoil.

The above species of shrubs and trees were planted at the same time in September, 2001. The trees were planted from stem cuttings at spacing of  0.2*0.5m for Mulberry and Trichanthera,  0.2*1.0m for Hibiscus and 1*1 for  Muntingia calabuara,  which was planted by seedlings when their height was about 50 cm. The plot size was 25m for each of the trees. The foliages were harvested when the plants reached 1 m height except for "Trung Ca" which was 2.5 m. The cutting point was  50 cm above ground level.

Samples of the foliages (leaves, petioles and young stems) were collected at harvest time and analysed according to the official methods of AOAC (1990). Cell wall components (NDF, ADF) were determined according to Van Soest et al (1991).  Rumen degradability was determined according to rskov et al (1980) using three fistulated crossbred cattle. In vitro  gas production method was measured following the method of Menke and Steingass (1988). Rumen degradation and gas production parameters were estimated by fitting the exponential equation of McDonald (1981):
 

P = a + b (1 - e -ct)

using the F-curve software running on Microsoft Xcel.


Results and discussion

 Harvesting and foliage production

Table 1: Planting and harvesting details and foliage production of Hibiscus rosa, Muntingia, Morus alba and Trichanthera

 

Hibis.

Munt.

Morus.1

Morus.2

Trichan.

Tree spacing (m)

0.2 x 1

1 x 1

0.2 x 0.5

0.2 x 0.5

0.2 x 0.5

Age of first cutting (months)

10

3

8

8

10

Plant height at 1st cutting (cm)

101

250

105

139

109

Biomass yield (kg/ha)

 

 

 

 

 

1st cutting

17417

13500

11000

13114

26476

2nd cutting

13908

-

8200

9032

15904

3rd cutting

9700

-

5100

4700

16304

Mean of 3 cuttings 13675   8100 8949 19561

Cutting interval (weeks)

9

-

9

9

10

Estimated biomass (tonnes/ha/year)

55 to 60

40 to 50

40 to 45

40 to 45

80 to 100

Ratio leaf: stem

3.00

1.50

1.50

1.25

1.35

Morus.1: Morus alba (local variety, Dau O);   Morus.2: Morus alba (local variety, Dau Co)

Trichanthera and Hibiscus had higher biomass yield than Mulberry and Muntingia (Table 1). It has been observed that all the above species grow faster in the spring season compared with the winter season in central Vietnam (Nguyen Xuan Ba, unpublished data). There appear to be good prospects for using Trichanthera,  Hibiscus and Mulberry as ruminant feeds in the dry season in central Vietnam. The Muntingia species is not suitable for repeated cutting.  

Nutritive value

The crude protein of the dry matter of the leaves and stems varied from 12 to 23 % (Table 2).  The NDF contents were high in all the plants.

Table 2: Chemical composition of Hibiscus rosa,  Muntingia,  Morus alba and Trichanthera ( dry matter basis except for DM which is on fresh basis)

 

DM

CP

CF

Ash

NDF

ADF

Ca

P

Hibis. leaves

20.5

18.4

15.6

13.4

30.4

14.2

Hibis. leaves and young stems

20.0

17.2

17.9

13.4

34.0

19.0

Munt. leaves

37.0

16.0

14.1

11.6

24.5

12.6

Munt. leaves and young stems

40.0

14.3

20.2

12.0

34.7

22.6

Trichan. leaves

14.0

12.4

17.4

23.5

44.9

25.9

Trichan. leaves and young  stems

13.0

12.0

18.0

24.7

45.2

25.9

Morus 2. leaves

31.0

24.3

9.5

13.2

32.9

15.6

1.9

0.6

Morus 2. leaves and young stems

28.0

22.6

9.6

11.8

34.5

14.8

1.8

0.6

Morus 1. leaves

37.0

22.2

8.8

15.5

31.0

15.0

2.8

0.4

Morus 1. leaves and young stems

35.5

23.1

10.9

13.7

32.4

15.4

2.8

0.5

DM degradability at 24 h was highest for Hibiscus followed by Mulberry with lower values for Trichanthera and  Muntingia (Table 3).

Table 3: In sacco degradability (mean values and SE) of leaves and stems of Morus alba, Hibiscus rosa, Muntingia and Trichanthera gigantea

 

Incubation time (hr)

8

16

24

48

72

96

Hibis. leaves

34.85.1

78.56.4

92.10.9

93.30.2

93.50.1

93.90.3

Hibis. leaves and young stems

44.31.6

55.11.3

71.91.8

89.51.2

91.20.4

91.40.3

Munt. leaves

30.60.5

33.92.7

39.66.2

67.13.3

75.20.5

79.11.9

Munt. leaves and young stems

32.50.6

36.51.8

46.54.2

63.81.7

68.71.0

70.10.7

Trichan. leaves

36.10.5

41.70.3

48.25.9

79.90.7

84.73.9

91.60.1

Trichan. leaves and young  stems

37.70.4

43.40.1

46.83.3

79.03.2

83.50.1

88.00.5

Morus 2. leaves

47.00.4

49.62.9

79.78.4

88.00.1

88.50.6

89.10.6

Morus 2. leaves and young stems

53.61.4

61.86.4

81.18.1

89.80.4

90.50.2

90.70.3

Morus 1. leaves

53.23.5

74.715.1

82.08.7

89.70.6

90.90.2

91.10.1

Morus 1. leaves and young stems

61.710.8

73.314.0

84.56.0

90.30.6

90.80.2

91.00.1

 

The washing loss (soluble cell contents) was higher for Mulberry than the other species.  The other  degradability parameters are difficult to interpret as apparently there are few differences among the species. However, it is known that the nutritive value of Trichanthera is relatively low when fed to goats (Keir et al 1997), whereas Mulberry has a high feeding value for goats (Theng Kouch et al 2003).   

Table 4: In sacco degradability characteristics of Mulberry, Hibiscus, Muntingia and Trichanthera

 

a

(%)

b

(%)

a + b (%)

c

(%/hr)

Washing loss

ED of water insoluble (%)

Lag time

(hr)

Hibis. leaves

-147

241

93.9

0.176

14.1

79.8

6.3

Hibis. leaves and young stems

17.4

76.2

93.6

0.050

15.5

78.1

0.0

Munt. leaves

16.0

77.5

93.5

0.019

28.2

65.3

9.0

Munt. leaves and young stems

18.3

56.5

74.8

0.030

30.1

44.7

7.9

Trichan. leaves

19.4

84.0

100

0.022

34.0

66.0

8.8

Trichan. leaves and young  stems

21.7

77.7

99.4

0.022

36.0

63.4

9.3

Morus 2. leaves

15.8

75.0

90.8

0.057

40.4

50.4

7.0

Morus 2. leaves and young stems

26.0

65.8

91.8

0.062

44.1

47.7

5.2

 

Gas production at 48h was highest for Hibiscus followed by the Mulberry with lowest values for Trichanthera and Muntingia (Table 5). There were no consistencies, however, in the fitted curve parameters, which indicated higher rate constants for Mulberry compared with Hibiscus, yet 48h gas production showed the contrary.  The unreliability of the fitted curve procedures is shown in Figures 1 and 2. There was a close relationship (R = 0.70) between the 48h degradation and gas production data (Figure 2) but no relationship (R = 0.07) between the "a+b" parameters for the two methods (Figure 1).

Table 5: Gas production from the fermentation of  200 mg of DM of Mulberry, Hibiscus, Muntingia and Trichanthera

 

Gas production, ml

Parameters

24

48

72

96

a+b

c

Hibis. leaves

39.7

46.7

48.8

49.8

49.2

0.075

Hibis. leaves and young stems

35.2

41.4

43.4

45.0

44.0

0.075

Munt. leaves

15.7

23.8

27.4

29.4

31.7

0.027

Munt. leaves and young stems

11.6

19.5

20.0

21.7

22.8

0.033

Trichan. leaves

13.2

22.4

24.4

26.1

27.7

0.032

Trichan. leaves and young  stems

13.5

22.6

24.3

26.0

27.6

0.032

Morus 2. leaves

35.5

39.0

41.1

41.4

40.6

0.104

Morus 2. leaves and young stems

25.4

30.6

31.8

31.8

31.2

0.097

Morus 1. leaves

31.4

36.2

36.7

36.1

36.7

0.086

Morus 1. leaves and young stems

32.2

35.7

38.5

39.2

38.0

0.095

 

Figure 1: Relationship between a+b parameters for in sacco and gas production Figure 2: Relationship between 48h in sacco DM degradation and gas production at 48h

 

Conclusions and recommendations

  • Based on this study, it can be concluded that some indigenous trees together with the introduced Trichanthera gigantea can be grown as protein sources for ruminants in central Vietnam.

  • These trees grow well in poor quality soil, at high ambient temperature, with low levels of management.

  • Morus alba and Hibiscus rosa appear to have a higher nutritive value than Trichanthera gigantea with poorest values for the  Muntingia.

 

Acknowledgements

This research was partially financed by the bilateral SAREC project 2000-2002.


References

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Received 25 March 2003; Accepted 16 June 2003

 

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