Livestock Research for Rural Development 15 (7) 2003

Citation of this paper

Studies on utilization of trees and shrubs as the sole feedstuff by growing goats; foliage preferences and nutrient utilization 

Theng Kouch, T R Preston and J Ly*

University of Tropical Agriculture Foundation

Royal University of Agriculture

Chamcar Daung, Phnom Penh, Cambodia
kouch@utafoundation.org
regpreston@utafoundation.org


* Present address: Swine Research Institute,
PO Box 1, Punta Brava, La Habana, Cuba
jlyca@yahoo.com

 

Abstract

A study was made of different ways of offering three tree foliages (Mulberry [Morus alba], Jackfruit [Artocarpus heterophyllus] and Cassava [Manihot esculenta] to goats. The feeding methods were: offering fresh leaves (L) or foliage (F) in the feed trough or the foliage hanging on the side of the pen (FH). The treatments were allocated to each foliage in three successive  3*3 Latin square arrangements to 3 growing goats confined in metabolism cages. The evaluation consisted of a study of the pattern of feed intake and nutrient digestibility.

In all the plant species examined, the leaves had a higher DM, ash and crude protein concentration than the foliage (leaves plus stems). On all three plant species the goats ate more dry matter in a shorter time when they were offered the foliage hanging from the roof of  the cage. Intake was lowest and eating time longest when only the leaves were offered in the feed trough. Ruminating rate was not influenced by source of foliage or method of feeding.

DM and OM digestibility followed the same pattern as DM intake, with highest values for hanging foliage and lowest for leaves fed separately. For jackfruit and cassava the N retention was highest for hanging foliage and lowest for the leaves fed in the trough. There were no differences in N retention for the different ways of offering the mulberry foliage. There was no effect of feeding method on ruminal pH and protozoa counts. Rumen ammonia levels were very high (from 400 to 1000 mg/litre) and were not affected by offer method or source of foliage.

It is concluded that dry matter intake and digestibility of tree foliages by goats will be higher when the leaves are attached to the stem and hungfrom the walls of the pen, compared with putting the branches or only the leaves in a feed trough. 

Key words: Behaviour, digestibility, foliage, goats, intake, N retention, shrubs, trees

 

Introduction

Cambodia is basically an agrarian country where farming systems are traditionally based on rice cultivation (Yang Saing Koma 1997;  Maclean 1998). In this context, it has been recognized that large ruminants, such as local breeds of cattle and buffaloes, have occupied an important position as the livestock component of the systems (Maclean 1998). Nevertheless, small ruminants such as goats have been used for meat production in certain areas of the country (Tilchit 1981; Delvert 1982; Yang Saing Koma 1997; Maclean 1998), as occurs in other neighboring regions (Devendra 1993). However, the practice of goat husbandry has not been extensively used in Cambodia as yet (see Maclean 1998), although goat production would appear to be more feasible for poor farmers, from the point of view of financial inputs.

The traditional management and system procedure for goat production by small-holders in Cambodia has consisted of day-time grazing on natural pasture and housing usually in a pen with raised floors at night-time (Sorn San 2002). It is quite common for the farmers to offer tree foliages during periods of feed shortage, such as during the dry season and in times of flooding (Theng Kouch et al 2003).

The use of foliage from trees and shrubs  in animal nutrition has focused the attention of many researchers, due to the fact that these feed resources are locally available, perennial sources of feeds (Singh 1995; Leng 1997), rich in protein and particularly appropriate for small ruminants (Van Eys et al 1986; Robertson 1988; Chen et al 1992; Norton 1994; Kaitho 1997; Seng Sokerya and Rodriguez 2001). In this connection,  jackfruit (Artocarpus heterophyllus), mulberry (Morus alba) and cassava (Manihot esculenta) are multipurpose plants that could be successfully used in goat production in Cambodian conditions of animal husbandry, due to the fact that their agronomy is well known in practice by the farmers and, on some occasions, have been given to ruminants for feeding purposes (Theng Kouch et al 2003).

The use of jackfruit and other tree and shrub leaves is a common practice for feeding goats in other regions of South East Asia (Dahlanuddin 2000; Nguyen Thi Mui et al 2001). Jackfruit plantations are mainly directed to fruit production although it has been estimated that from 20 to 200 kg of green material can be harvested per tree annually  (Von Carlowitz 1986). Mulberry trees are usually cultivated for silkworm feeding, although a trend for this plant to be used for feeding other animals is recently reported (Sánchez 2000). Cassava foliage is mainly available as a crop residue after harvesting the roots. Nevertheless, it has been claimed that cassava cultivation for forage purpose could be an advantageous alternative in integrated farming systems (Preston 2001).   

Interestingly, according to the World Bank (1992), the mixed-deciduous forest in Cambodia is the largest undisturbed ecosystem existing in continental Asia. However, tree cultivation for animal feeding with periodically harvested foliage is not often found. Very little is known about the use of tree and shrubs foliage for feeding goats in Cambodia (Him Aun 2002), nor are there many details of goat production systems in the country (Sorn San 2002).

The objective of the present communication is to report several observations made on the feeding behaviour, intake and digestibility of tree foliages in growing goats. The approach was based on observations by Preston (2002, personal communication)  that, in Vietnam, when goats were offered jackfruit foliage as the sole diet, they preferred to eat leaves attached to the stems rather than the separated leaves offered in the feed trough The hypothesis to be evaluated was therefore that feed intake in goats would be higher for other tree foliages when these were fed hanging in the pen rather than as separated leaves.

 

Materials and Methods

Location

The study was carried out at the University of Tropical Agriculture on the campus of Royal University of Agriculture, in Cambodia, from May to September, 2002. 


Treatments and design

Foliage of jackfruit (Artocarpus heterophyllus), mulberry (Morus alba) and cassava (Manihot esculenta) were used throughout the study. Mulberry and cassava were from plantations harvested periodically and located in the UTA Ecological Farm. The jackfruit foliage was obtained from nearby farmers.

Three treatments were used for every one of the three foliages evaluated, and consisted of offering as the only ration to the animals either leaves (L) or leaves and stems (F) placed in the feed trough, or leaves and stems offered hanging (FH), tied to a bamboo stick over the cage. The goats were allocated to the treatments at random, after they were adapted to confinement in individual pens during a preliminary period of two days.

The foliage or leaves+petioles for each plant species were offered to 3 goats in according to three successive 3*3 Latin square arrangements (one for each plant species)  with periods of 16 days for each square, the first 10 days for adaptation to the diet, and the following five days for determination of intake, nutrient digestibility, and N retention. Feeding behaviour (time spent eating and ruminating) was recorded on three 24 hour occasions on days 5, 10 and 15 of each period. On day 16 rumen samples were obtained for every animal using a stomach tube. The allocation of animals to treatments for each source of foliage / leaves is shown in Table 1.

 

Table 1. Experimental layout for each source of foliage / leaves

Period

Goat 1

Goat 2

Goat 3

1

L

FH

F

2

F

L

FH

3

FH

F

L

 

The chemical characteristics of the foliages  (leaves and petioles attached to green stems), and  leaves plus petioles, from plant terminal branches of approximately 25 to 40 cm length, are shown in Table 3. 


Animals and housing

Three male crossbred goats averaging 20 ± 1.5 kg live body weight were used for the evaluation of every plant species. The goats were housed in metabolism cages (1.0x0.8 m), elevated 0.8 m and allowing the separate collection of faeces and urine. The cages were made of wood, bamboo and rattan and were situated in a shed with roof and open sides  (Photo1: Him Aun 2002) .

 Photo 1: The locally made bamboo cage for measuring digestibility and N retention


Feeding management

The feeds were offered ad libitum. The mulberry and cassava materials were offered fresh, immediately after harvesting, whereas jackfruit foliage was obtained every two days. The feed was offered in three methods comprising either leaves, or leaves and stems offered in the trough, or leaves and stems offered hanging after tying to a bamboo pole over the cage. Before preparing the feeds, the ratio of leaves plus petioles and old stems, was determined by sampling 3 times (1 kg per time) the foliage. The leaves plus petioles were separated from the old stems then weighed (Table 2). The goats were offered the feed three times per day (8:00 AM, 11:00 AM and 2:00 PM).

Table 2: Ratio of leaves + petioles and stems (25 to 40 cm branches) of the three plant species (% fresh basis)

 

Leaves + petioles

Stem

Mulberry

76.5±

23.5

Jackfruit

71.5

28.5

Cassava

73.3

26.8



Measurements
Intake, digestibility and N retention

Feed offered and refused, output of  faeces and urine, was recorded daily during the last 5 days of each period. Samples of feed offered and refusals were taken daily and analysed for DM and N. Faeces were put in plastic bags in the freezer (-20 °C). Urine was collected in a bucket containing enough H2SO4 solution to maintain a pH of 4 or lower. Nutrient digestibility and N balance were calculated by standard procedures outlined for the direct estimation of animal digestibility (Crampton and Harris 1969). 


Feeding behaviour

Eating and ruminating time was continuously monitored by two people during periods of 24 hours on days 5, 10 and 15 in each experimental period. The time spent eating and ruminating was recorded.

The intake rate and ruminating rate were calculated by:


Rumen environment

Rumen fluid samples were collected by stomach tube two hours after feeding on day 16, at the end of each experimental period, to measure rumen ammonia, pH and protozoa population. About 15 ml of rumen fluid collected from each goat were transferred into individual containers, filtered through two layers of cotton cloth and thereafter two drops of concentrated H2SO4 were added to inactivate rumen microbial activity. Ten ml of acidified rumen liquor were mixed with 4 ml of saline formaldehyde solution and the treated samples were stored in refrigeration until counting. Protozoa counting was conducted by placing one drop of sample onto a slide and then covering with a cover-slip. The protozoa number was counted 20 times under a 10x magnification in a microscope. This procedure was repeated 2 to 3 times per sample. 


Calculation of the number of protozoa:

The counting of 20 times for each slide was recorded and then the average of the slides for one sample was calculated. This represented the number of protozoa in the microscope field (P1, protozoa count). In this counting, the protozoa were divided into large which were roughly 80 µm and small which were roughly 20 µm.

­       Use A as the area of the microscope field at 10x magnification, A=2.66 mm², and B as the area of rumen liquor under the cover-slip, B=144 mm².  B/A=54.2.

­       P2 the number of protozoa per B. P2 = P1*B/A  = P1* 54.2

­       The volume of rumen liquor in one drop under the cover slip (C) was calculated by adding 100 drops to a weighing bottle. The volume of liquor under the cover slip can then be estimated; i.e. one drop= Wt/ 100. In this case C = 0.043 ml.

­       P3 the number of protozoa per 1 ml of dilute sample. P3 =  P2/C = [P1*(B/A)]/C = (P1*54.2/ 0.043)

­       Knowing the counts of each field (P1), the volume of liquor under the cover slip, area of microscope field A and area of cover slip B, the density of protozoa  (P3) was estimated in the diluted sample.

  ­       Use D as the volume of rumen fluid per ml of diluted sample, 10ml of rumen fluid plus 4 ml of diluent. D = 10/14

­       Protozoa count per ml of rumen fluid (P4) was then:

P4 = P3/D = P3 * 1.4 = protozoa count x 1.4 x 54.2/ 0.0556 


Chemical analysis

Feed and faecal samples were dried by microwave radiation to measure the DM content (Undersander et al 1993). Total N of feed, faeces and urine was measured by the Kjeldahl procedure as outlined by the AOAC (1990). The ash content of feed and faeces was determined following the AOAC (1990) recommendations and therefore, the organic matter was assumed to be the result of subtracting the percentage of ash from 100. The water soluble DM and N were determined according to Ly and Preston (2001).

Rumen pH was determined by glass electrode measurements in a digital pH meter and NH3 was estimated by steam distillation according toi AOAC (1990).  


Biometrical analysis

The data were analyzed according to the analysis of variance technique and means separation was conducted by the Duncan’s multiple range and multiple F test (Steel and Torrie 1980) using the general linear model (GLM) procedure in the software of  MINITAB (release 13.31).

The mathematical model used was:

Yijk = M + Ai + Bj + C(i,j),k + eijk

where:

Yijk      =   Independent variable (Intake, apparent digestibility, etc)

 M       =   Overall mean

Ai        =   Effect of period

Bj         =   Effect of goats

Ck        =   Effect of treatment

eijk      =   Effect of random error 

 

Results

Feed composition

During the experiment all animals were in good health and in positive live weight balance. In all the plant species examined, leaves had higher contents of  DM, ash and crude protein than the foliage (Table 3).

Table 3. Chemical characteristics of the foliages and leaves (plus petioles)  (% in dry basis)

 

Mulberry

Jackfruit

Cassava

Leaves

Foliage1

Leaves

Foliage

Leaves

Foliage

Dry matter

23.6

20.11

36.23

32.83

19.45

18.24

Ash

15.8

14.47

10.41

8.96

11.36

6.79

Organic matter

84.22

85.53

89.56

91.04

88.64

93.21

Crude protein

24.94

21.56

12.81

12.38

21.81

20.19

DM solubility1

34.89

34.13

16.63

17.00

30.38

31.47

N solubility1

56.79

51.59

33.66

46.16

44.78

40.55

1 See text for details

There were no marked difference in DM solubility between leaves and foliage within every type of plant sample analyzed. However, jackfruit had a relatively low DM solubility as compared to mulberry and cassava. N solubility was variable, according to the type of sample evaluated. Overall, N solubility was high and with no remarkable differences between leaves and leaves plus stems. On the contrary, N solubility in jackfruit was relatively low, as contrasted to that of mulberry, with higher values for leaves and stems as compared to leaves alone. On the other hand, cassava leaves showed fairly high values for N solubility, although lower than that of mulberry. However, the inclusion in the feed of cassava stems (foliage) resulted in a slight decrease in N solubility. 


Voluntary feed intake

There were remarkable differences in feed intake in response to the method of offering the feed (Table 4).  DM intake was highest in the three plant species when the foliage was presented hanging in the cage, and was lowest when the leaves were offered separately in the feed trough.

Table 4. Voluntary feed intake of goats according to to the method of offering the feed

 

Leaves in trough

Foliage in trough

Foliage hanging

SEM/Prob. 

Mulberry

 

 

 

 

DM intake, g/day

775a

917ab

1033b

42.0/0.01

DM intake, % body weight

3.34

3.91

4.58

0.42/0.20

Jackfruit

 

 

 

 

DM intake, g/day

827a

918a

1145b

31.4/0.001

DM intake, % bodyweight

3.50a

3.85a

4.87b

0.18/0.004

Cassava

 

 

 

 

DM intake, g/day

780a

822a

1008b

51.8/0.044

DM intake, % body weight

3.14a

3.44a

4.16b

0.11/0.002

ab Means without letter in common in the same row differ significantly (P<0.05)

 

There were apparent differences in the rate of adaptation to the foliages and leaves of each plant species. It was observed that the goats avidly consumed the fresh leaves and the young stems of mulberry and Jackfruit, immediately the feeds were offered. In contrast, the rate of adaptation to the cassava was much slower and required some 7 days before the maximum intake was achieved.

For all plant species, the time spent eating was shortest for foliage hanging in the cage and longest for leaves offered in the trough (Table 5).  The effect of offer method on rumination time varied with plant species. In the case of cassava, it was shorter for foliage hanging in the cage compared with leaves in the trough. For mulberry and jackfruit there were no differences due to offer method.  The ratio of time spent eating to time ruminating also varied according to plant species. The ratio was least for hanging foliage and highest for leaves in the case of mulberry and jackfruit, with the opposite response in the case of cassava.

 Figure 1: Dry matter intake by goats of foliage / leaves of three plant species,
according to the method of offering the feed

 

Table 5. Daily eating and ruminating time of goats according to the method of offering the feed

 

Leaves in trough

Foliage in trough

Foliage hanging

SEM/Prob

Mulberry

 

 

 

 

Eating, min/24h

359a

301b

249b

15.1/0.006

Ruminating, min/24h

183

206

218

20.0/0.59

Eating and ruminating, min/24h

542

507

467

32.9/0.29

Eating:ruminating ratio

1.99a

1.48b

1.16b

0.13/0.01

Jackfruit

 

 

 

 

Eating, min

410a

382a

325b

9.26/0.002

Ruminating, min

446

442

412

15.4/0.33

Eating and ruminating, min

856a

824a

737b

22.1/0.023

Eating:ruminating ratio

0.92a

0.86a

0.79b

0.03/0.045

Cassava

 

 

 

 

Eating, min

458a

402b

351c

7.2/0.001

Ruminating, min

403a

369b

261c

6.56/0.001

Eating and ruminating, min

861a

771b

612c

11.2/0.001

Eating:ruminating ratio

1.14a

1.09a

1.35b

0.03/0.003

abc Means without letter in common in the same row differ significantly (P<0.05)


For all the plant species, the rate of eating,  expressed as g of feed DM consumed per minute, was highest when the foliage was hung in the cage and lowest when the leaves were offered separately (Table 6; Figure 2). The rumination rate (g feed DM intake per minute of time spent ruminating) was highest for hanging the foliage, and lowest for the separated leaves, in the case of jackfruit and cassava, with no apparent differences due to offer level for the mulberry. The fastest rate of eating was on the mulberry hanging foliage (about 4 g/minute), followed by the jackfruit (3.5 g/minute) and the cassava (2.8 g/minute).

Figure 2: Intake rate of three plant species by goats according to method of offering the feed

 

Figure 3: Rumination rate of three plant species by goats according to method of offering the feed


Digestibility indices

There were differences in the dry matter content of the faeces between plant species but not between the methods of offering the feed (Table 6), with the lowest value for mulberry (45 to 46%) and much higher values (64 to 70%) for jackfruit and cassava. There was no effect of the offer method nor the plant species on the pH of the faeces which was alkaline in all cases.

Both feeding method and plant species affected the digestibility of dry matter and organic matter (Figure 4). For all species the apparent digestibility coefficients were highest for foliage hanging in the cage and lowest for leaves fed in the trough. Digestibility coefficients were high for Mulberry (70 to 79%) and cassava (69 to 80%) and considerably lower for jackfruit (48 to 63%).


Table 6. Digestibility indices of three plant species for goats according to the method of offering the feed

 

Leaves in trough

Foliage in trough

Foliage hanging

SEM/Prob

Mulberry

 

 

 

 

Faecal indices

 

 

 

 

pH

7.97

8.25

8.32

0.35

DM, %

44.6

43.89

46.63

5.92

DM digestibility, %

70.8

76.1

79.3

2.8/0.18

Organic matter digestibility, %

79.9

80.5

83.4

2.2/0.5

Jackfruit

 

 

 

 

Faecal indices

 

 

 

 

pH

7.69

7.55

7.64

0.19

DM, %

64.0

64.4

70.1

3.36

DM digestibility, %

48.5

52.5

63.3

4.6/0.14

Organic matter digestibility, %

49.0

52.9

64.3

4.1/0.19

Cassava

 

 

 

 

Faecal indices

 

 

 

 

pH

8.20

7.50

8.28

0.28

DM, %

66.5

66.4

63.5

4.66

DM digestibility, %

68.8

73.1

80.1

2.9/0.08

Organic matter digestibility, %

71.2b

75.6b

82.1a

2.6/0.06

abc Means without letter in common in the same row differ significantly (P<0.05)


Figure 4: Digestibility of three plant species by goats according to method of offering the feed


For all plant species daily N retention was highest for hanging foliage in the cage and lowest for leaves fed in the trough (Tables 7 to 9; Figure 5), with differences being more marked for jackfruit (P=0.001) and cassava (P=0.04) than for mulberry (P=0.35). Although not strictly comparable, it was apparent that daily N retention was higher on mulberry (8.4 to 12.0 g/day) than on jackfruit and cassava (3.6 to 7.9 and 3.6 to 8.5, respectively).


Table 7. N balance of goats according to the method of offering the feed (mulberry)

 

Leaves in through

Foliage in trough

Foliage hanging

SEM/Prob.

N balance, g/day

 

 

 

 

Intake

33.5

30.4

35.4

1.89

Faecal output

4.89

5.30

5.40

0.79

Digestion

28.6

25.1

30.0

1.31

Urine output

18.6

16.6

18.0

0.93

Total output

23.5

22.0

23.4

0.85

Retention

9.94

8.43

12.0

1.61/0.35

Digestibility, %

85.6

82.7

84.7

1.8/0.55

Retention, % intake

29.5

27.0

33.9

3.8/0.48

Retention, % digestion

34.5

33.0

39.9

5.0/0.61

 

Table 8. N balance of goats according to the method of offering the feed (jackfruit)

 

Leaves in through

Foliage in trough

Foliage hanging

SEM/Prob.

Balance, g/day

 

 

 

 

Intake

19.5

19.2

22.0

1.47

Faecal output

10.9

11.4

9.56

1.16

Digestion

8.67

7.80

13.40

1.12

Urine output

5.06

3.81

5.43

1.03

Total output

15.9

15.3

15.0

1.57

Retention

3.61a

3.97a

7.94b

0.43/0.001

Digestibility, %

44.4a

40.6a

58.0b

3.8/0.039

Retention, % intake

19.3a

20.6a

34.6b

2.5/0.008

Retention, % digestion

43.4

51.2

60.2

6.0/0.27

ab Means without letter in common in the same row differ significantly (P<0.05)

 

Table 9. N balance of goats according to the method of offering the feed (cassava)

 

Leaves in trough

Foliage in trough

Foliage hanging

SEM/Prob.

Balance, g/day

 

 

 

 

Intake

27.7

29.8

35.7

2.54

Faecal output

6.82

6.11

5.60

1.28

Digestion

20.9

23.7

30.1

2.34

Urine output

16.7

17.2

20.1

2.60

Total output

23.5

23.3

25.7

2.95

Retention

3.55a

5.89b

8.50c

1.05/0.043

Digestibility, %

75.9a

79.5ab

83.9b

3.6/0.33

Retention, % intake

14.4

20.1

25.3

4.7/0.33

Retention, % digestion

19.0

25.4

30.6

6.1/0.46

abc Means without letter in common in the same row differ significantly (P<0.05)


Figure 5: N retention of three plant species by goats according to method of offering the feed


There was no effect of method of feeding on pH, ammonia and protozoa numbers in rumen fluid (Table 10). Rumen ammonia levels and pH appeared to be higher, and protozoa numbers lower, for goats fed cassava as compared with the other plant species. Ammonia levels were extremely high in all cases.


Table 10. Rumen indices of goats according to the method of offering the feed

 

Leaves in trough

Foliage in trough

Foliage hanging

SEM

Mulberry

 

 

 

 

pH

6.59

6.51

6.57

0.21

NH3, mg/litre

933

928

812

169

Protozoa/ml x10-5

3.4

3.9

3.5

0.40

Jackfruit

 

 

 

 

pH

6.54

6.68

6.67

0.12

NH3, mg/litre

736

806

467

176

Protozoa/ml x10-5

2.6

2.5

2.8

0.1

Cassava

 

 

 

 

pH

7.18

7.01

7.05

0.15

NH3, mg/litre

938

906

1076

219

Protozoa/ml x10-5

2.2

1.8

1.8

0.2

 

Discussion

Feed characteristics

In general the chemical composition data for the three plant species in the current experiment are within the range of values reported by other researchers, with the exception of the protein in the jackfruit leaves which was lower than other reported values (Table 11).


Table 11. Literature values for chemical characteristics of the three plant species (% dry basis, except for DM which is on fresh material)

 

 

 

DM

 

Ash

Crude fibre

 

NDF

Crude protein

 

Reference

Mulberry

 

 

 

 

 

 

Leaves

-

14.3

-

24.6

18.6

Shayo  (1997)

Leaves

-

11.8

-

31.6

25.8

Kitahara et al (2002)

Leaves

25.4

-

-

-

16.1

Benavídes et al (2002)

Leaves

33.3

 

 

31.5

22.1

Ly et al (2001)

Leaves

23.6

 

 

 

24.9

This experiment

Jackfruit

 

 

 

 

 

 

Leaves

36.6

8.2

22.6

-

15.1

Devendra (1992)

Leaves

36

-

-

-

-

Keir et al (1997)

Leaves

32.9

-

-

-

16.63

Ly and Preston (2001)

Leaves

26.9

-

-

-

18.1

Dinh Van Binh et al (2001)

Leaves

40.8

-

-

68.0

17.1

Ly et al (2001)

Leaves

36.2

 

 

 

12.8

This experiment

Cassava

 

 

 

 

 

 

Stems

12.6

-

-

-

8.6

Him Aun (2002)

Petioles

11.7

-

-

-

14.5

Him Aun (2002)

Leaves

25.6

-

-

-

28.3

Him Aun (2002)

Leaves

-

5.56

25.70

-

17.3

Doan Thi Khang & Cu Xuan Dan (2001)

Leaves

18.8

9.6

-

38.3

25.2

Ly et al (2002)

Leaves

19.5

 

 

 

21.8

This experiment

 

The high DM and N water solubility values in the Mulberry are in agreement with other previous reports from this laboratory (Ly et al 2001). DM and N solubility of jackfruit leaves and foliage  were relatively low as compared to similar indices for mulberry and cassava foliage. These observations are in accordance with previous findings of Ly and Preston (2001). Variations in chemical composition of leaves reported by us and other workers could be attributed to differences in climatic conditions between the study areas. Another factor contributing to this difference could be the harvesting season and time, because leaves develop their structure and morphology according to their age and management (Audru et al 1991).


Eating, ruminating time and intake

The data on feed intake show quite clearly that goats eat more dry matter when offered foliages with the leaves attached to the stems than when the leaves are offered separately, and that foliages suspended from the roof of the cage support higher intakes than when they are offered in the feed trough. Foliage suspended in the cage most closely simulates the natural condition when goats browse trees and shrubs. It appears that the goats find it easier to bite the leaves when they are attached to stems offering some resistance to the action of eating, as is the case for hanging foliage compared with the foliage placed loosely in the feed trough. The higher eating rate by hanging the foliages compared with foliages offered loose (in the feed trough) confirms this supposition.  It was also apparent from observing the eating habits of the goats that they found it easier to bite the leaves of the mulberry and more difficult to bite those of the cassava, which was reflected in the higher rate of eating in the former.  The bunches of mulberry and jackfruit foliages hanging in the pen were more open than the bunches of cassava, which could have been another factor facilitating consumption. of the two former species.

The high voluntary intakes of the goats fed hanging mulberry foliage (4.6% of body weight) is supported by the findings of Rojas and Benavides (1994 cited by Sánchez 2000) that dry matter intake and milk production of goats offered a mixture of King grass and mulberry foliage increased to 5.5% of body weight as the level of mulberry was increased. The high DM intake of hanging jackfruit foliage (4.87% of body weight), despite its low digestibility,  agrees with the report of Keir et al (2997) that this foliage was much superior  to that from Trichanthera gigantea, even though in vitro and in vivo digestibility were lower than for the Trichanthera. 

There was no apparent toxicity effect due to feeding cassava foliage as the sole diet. However, the fact that the goats took longer to adapt to this foliage could be interpreted as being due to the time required for the rumen flora to become adapted to metabolizing the HCN presumably liberated in the rumen.  


Apparent digestibility and N retention

The high value for DM digestibility of the Mulberry foliage (79.2%) is similar to the findings of Jegou et al (1994 cited by Sánchez 2000), who reported DM digestibility values for leaves in the range of 78.4 to 80.8%. Benavides (1995 cited by Trujillo 2002) reported that digestibility of mulberry leaves can be in the range 80 to 93% and that of stems to be as high as 50%. These values are higher than those reported by Yao et al (2000), who claimed that in vitro organic matter digestibility in goats varied from 66 to 72% and from 56 to 61% for spring and autumn mulberry leaves, respectively. This latter value is similar to that reported by Singh et al (2000) for digestibility of the organic matter fraction (58%).

DM digestibility of the hanging jackfruit foliage (63.3%) was 14.8 units higher than for the separated leaves, an increase of some 30%. Keir et al (1997) reported a higher value of  66% but the leaves in this case were supplemented with a block of molasses-urea. Nguyen Thi Mui (2001) reported that the digestibility of jackfruit foliage was 52.6%, which is in agreement with the values for foliage fed in the trough in our experiment. The DM digestibility of hanging cassava foliage was very high (80.1%) and similar to that reported by Him Aun (2002) for cassava foliage hung in the cage and offered as the sole diet (83.5%). Wanapat et al (1997) reported a DM digestibility of 71% in cattle fed cassava foliage hay as the sole diet.

Nitrogen retention was highest for the hanging foliage and lowest when separated leaves were fed.  These trends mirrored the trends in voluntary DM intake although the relationship was not strong (r = 0.55). A closer relationship was observed  between N intake and N retention (r = 0.76).


Rumen ecology

The concentrations of ammonia in rumen fluid (in the range of 467 to 1076 mg/litre) were higher than has been reported in other studies with goats fed tree foliages. Thus Tran Quoc Viet (1997) encountered  199 mg/litre in growing goats fed jackfruit leaves while Nguyen Thi Hong Nhan (1997) reported levels of 180 mg/litre in lactating goats fed jackfruit leaves as the basal diet.

The concentrations encountered in our experiment are much higher than the suggested optimum levels (200 to 300 mg/litre) proposed by Perdok (1987) and almost certainly reflect the high intakes of the protein-rich leaves of all three plant species. While there is an energy cost associated with the urinary excretion of excess nitrogen, this is not necessarily a disadvantage if the goats are managed in an integrated farming system where both manure and urine are recycled as fertilizer or as substrate for earth worms. Nguyen Quang Suc et al (2000) reported that goat excreta supported faster growth of earth worms and produced a superior “ worm  compost than excreta from cattle or buffalo.

Protozoal numbers were not influenced by the method of offering the feeds. There was an indication that populations were lower on the cassava than on mulberry or jackfruit, which may be related with the presence of condensed tannins in the leaves of the cassava (Wanapat et al 1997). There are reports that feeding of cassava foliage is associated with reduced numbers of intestinal nematodes in buffaloes (Netpana et al 2001) and in goats (Seng Sokerya and Rodriguez 2001). 

The most difficult finding to explain is the higher digestibility of the DM and organic matter of all the plant species when offered as hanging foliage as compared with loose leaves and petioles in the feed trough. The differences for DM digestibility were 8.5, 14.8 and 11.3 units for Mulberry, Jackfruit and Cassava, respectively. It has to be assumed that these differences were related to the method of consuming the leaves. Eating time was shortest when the forages were suspended in the cage and longest when separated leaves were offered; and eating time was closely and negatively related  (R2 = 0.75) with N retention (Figure 6).


Figure 6: Relationship between eating time and N retention in goats fed foliages
or leaves from three plant species


It can be assumed that greater salivary secretion would occur when eating time was increased, from which it could be inferred that some compounds excreted in saliva were responsible for the depression in digestibility of the organic matter in the leaves.  This is an area meriting research. 


Conclusions

 

Acknowledgments

This paper formed part of the MSc thesis (MEKARN-SLU, Uppsala, May 2003), of the senior author, who wishes to express his gratitude to the MEKARN project, supported by  SIDA/SAREC of Sweden for financing this study; to Dr. T.R Preston, Director of the University of Tropical Agriculture (UTA), for advice and allowing the use of the research farm and laboratory facilities of UTA; to Dr J Ly for advising on analysis of data and the first correction of the draft paper. Thanks are also given to Mr. Roath for technical assistance throughout the experiment.

 

References

AOAC  1990  Official Methods of Analysis. Association of Official Analytical Chemists. 15th edition (K Helrick, editor). Arlington pp 1230

Audru  J, Labonne M, Guerine H and Bilha A A 1991  A traditional Forage Species among the Afar of Djibouti. Legume Tree and other Fodder Tree as Protein Sources for Livestock. FAO Anim. Prod. Health Paper 102, 277-293.

Benavides J E  1995  Arboles y arbustos forrajeros para las montañas americanas. En: Sistemas Pecuarios Sostenibles para las Montañas Tropicales. pp103-123 CIPAV, Cali, Colombia.

Benavídes J, Hernández I, Ésquivel J, Vasconcelos J, González J and Espinosa E  2002  Supplementation of grazing dairy cattle with mulberry in Costa Rica. Mulberry for Animal Production. FAO. Animal Production and Health Paper 147. 165-170

Black J L and P A  Kenney  1984  Factors affecting diet selection by sheep. II. Height and density of pasture. Australian Journal of Agricultural Research 35:565-578.

Burlison A J,  J  Hodgson and A W  Illius  1991  Sward canopy structure and the bite dimensions and bite weight of grazing sheep. Grass and Forage Science 46:29-38.

Chen C P,  Halim  R A and Chin  F Y  1992  Fodder trees and fodder shrubs in range and farming systems of the Asian and Pacific region. In: Legume trees and other fodder trees as protein sources for Livestock (A. Speedy and P L Pugliese, editors). FAO Animal Production and Health Paper No. 102 p 11-22

Crampton  E  W  and Harris L  E  1969  Apply Animal Nutrition. The Use of Feedstuffs in Formulation of Livestock Rations. Ed. W  H  Fueman. San. Fransisco. pp 753.

Dahlanuddin 2000  Development of feeding systems for goats based on available resources on Lombok, Indonesia. 1. Study on nutrient supply under farm conditions. International Foundation for Science. Stockholm pp 63

De Rosa G, Fedele V, Napolitano F, Gubitosi  L,  Bordi  A and Rubino R  1997  Diet Preferences in Adult and Juvenile Goats. Journal of Animal Science 65:457-463.

Devendra C  1992  Nutritional potential of fodder trees and shrubs as protein sources in ruminant nutrition. In: Legume trees and other fodder trees as protein sources for livestock (Speedy, A  and Pugliese, P L ). FAO-Animal Production and Health Paper 102: 95-113

Devendra  C  1993  Goats and sheep in Asia. In: Small ruminant production in the humid tropics (M. Wodzicka-Tomasweska, S  Gardiner, A  Djajanegara, I M  Mastika and T R  Viradarya, editors) Sebelas Maret University Press p 1-33

Dinh Van Binh, Ngo Tien Dzung, Le Viet Ly  2001  Leaves of Trichantera gigantea, Jack Fruit (Artocarpus hetecophylus), Banana  (Musa sp) and Acacia mangium as protein sources for lactating goats fed a basal diet of rice straw and sugarcane tops  Proceeding – Workshop on improved utilization of by-products for animal feeding in Vietnam.

Doan Thi Khang and Cu Xuan Dan  2001  Chemical composition of several crop by products as animal feeds in Vietnam. Proceeding Workshop on Improved Utilization of By-products for Animal Feeding in Vietnam-NUFU Project. http://www.vcn.vnn.vn/sp_pape/spec_5_4_2001_9.htm

Jayal  M M and Kehar N D  1962  A study on the nutritive value of mulberry (Morus indica) tree leaves. Indian Journal of Dairy Science, 15: 21-27.

Jegou  D, Waelput  J J and Brunschwig  1994  Consumo y digestibilidad de la materia seca y del nitrógeno del follaje de Morera (Morus sp.) y Amapola (Malvabiscus arboreus) en cabras lactantes. In J  Benavides, ed. Arboles y arbustos forrajeros en América Central, p. 155-162. Volumen I. Turrialba, Costa Rica, CATIE.

Hodgson  J  1985  The control of herbage intake in the grazing ruminant. Proceedings of the Nutrition Society 44:339346.

Huston  J  E  and Pinchak  W  E  Range Animal Nutrition, http://cnrit.tamu.edu/rlem/textbook/Chapter2.htm#index1#index1 . In text book: Gazing management, http://cnrit.tamu.edu/rlem/textbook/textbook-fr.html .

Illius  A W,  Gordon I J,   Milne J D and Wright  W  1995  Costs and benefits of foraging on grasses varying in canopy structure and resistance to defoliation. Functional Ecology 9:894-903.

Kaitho  R J  1997  Nutritive value of browses as protein supplement to poor quality roughages. PhD thesis. Wageningen Agricultural Univesity. Wageningen

Kitahara  N, Shibata  S  and Nishida 2002  Management and Utilizationof Mulberry for Forage in Japan. 1. Productivity of the Mulberry-pasture association System and nutritive Value of Mulberry. Mulberry for Animal Production. FAO. Animal Production and Health Paper 147. 235-240

Keir  B, Nguyen Van Lai, Preston  T  R  and Orskov  E  R  1997a  Nutritive value of leaves from tropical trees and shrubs: 1. In vitro gas production and  in sacco rumen degradability. Livestock Research for Rural Development  (9) : http://www.cipav.org.co/lrrd/lrrd9/4/bren941.htm

Keir  B,  Dinh Van Binh, Preston  T  R  and Orskov  E  R  1997b  Nutritive value of leaves from  tropical trees and shrubs: 2. Intake, growth and digestibility studies with goats. Livestock Research for Rural Development  (9): http://www.cipav.org.co/lrrd/lrrd9/4/bren942.htm

Leng  R A  1997  Tree foliage in ruminant nutrition. FAO Animal Production and Health Paper No 139. Rome pp 100

Laca  E  A, Ungar  E  D, Seligman  N  and Demment  M  W  1992  Effect of sward height and bulk density on bite dimensions of cattle grazing homogeneous swards. Grass and Forage Science 47:91-102.

Ly J and Preston T  R  2001  In vitro estimates of nitrogen digestibility for pigs and water-soluble nitrogen are correlated in tropical forage feeds. LRRD (13)1. http://www.cipav.org.co/lrrd/lrrd13/1/ly131.htm

Ly  J, Pok Samkol and Preston  T  R  2001 Nutritional evaluation of tropical leaves for pigs: Pepsin/pancreatin digestibility of thirteen plant species. LRRD (13)5. http://www.cipav.org.co/lrrd/lrrd13/5/ly135.htm

Ly J, Pok Samkol, Chhay Ty and Preston T R  2002  Nutritional evaluation of crop residues for pigs; pepsin/pancreatin digestibility of seven plant species. LRRD (14)1. http://www.cipav.org.co/lrrd/lrrd14/1/ly141b.htm

Maclean  M  1998  Livestock in Cambodian rice farming systems. Cambodia-IRRI-Australia Project. Phnom Penh pp 104

Martin Orue S M, Balcells  J, Vicente F  and Castrillo  C  2000  Influence of dietary rumen-degradable protein supply on rumen characteristics and carbohydrate fermentationin beef cattle offered high-grain diets. Anim. Feed Sci. Techn. 88:59-77.

McDonald P, Edwards R A, Greenhalgh  J F D and Morgan C A  1995  Feed Intake in Ruminants. Animal Nutrition, 425-433.

Netpana N, Wanapat M, Poungchompu O and Toburan W 2001 Effect of condensed tannins in cassava hay on fecal parasitic egg counts in swamp buffaloes and cattle. In: Proceedings International Workshop on Current Research and Development on Use of Cassava as Animal Feed. T R Preston, B Ogle and M Wanapat (Ed) http://www.mekarn.org/proc-cass/netp.htm

Nguyen Quang Suc, Le Thi Thu Ha and Dinh Van Binh 2000 Manure from Rabbits, Goat Cattle and Buffaloes as Substrate for Earthworms. Workshop-Seminar. Making better Use of Local Feed Resources. SAREC-UAF, January, 2000.

Nguyen Thi Hong Nhan 1997  Effect of sugar cane juice on milk production of goats fed a basal diet of jackfruit (Artocarpus heterophyllus) leaves. In Proceedings Regional Seminar-Workshop on Better use of locally available feed resources in sustainable livestock-based agricultural systems in SE Asia (Editors: T R Preston and Kenji Sato). FAO Project GCP/RAS/143/JPn; Ho Chi Minh City (pp: 62-65)

Nguyen Thi Mui, Ledin I,  Uden  P and Dinh Van Binh  2001  Effect of replacing a rice bran-soya bean concentrate with jackfruit (Artocarpus heterophyllus) or flemingia (Flemingia macrophylla) foliage on the performance of growing goats. Livestock Production Science 72:253-262

Norton  B W  1994  Tree legumes as dietary supplements for ruminants. In: Forage tree legumes in tropical agriculture (R.C  Gutteridge and P M  Shelton, editors). CAB International. Wallingford p 202-215

Perdok H B 1987 Ammoniated Rice Straw as a Feed for Growing Cattle. PhD Thesis University of New England, Armidale: NSW, Australia

Prasad  P E  and Reddy  M R  1991  Nutritive value of mulberry (Morus alba) leaves in goats and sheep. Indian Journal of Animal Nutrition, 8(4): 295-296.

Preston T R  2001 Potential of cassava in integrated farming systems. International Workshop on Current Research and Development on Use of Cassava as Animal Feed. Khon Kaen University, Thailand.

Robertson  B M 1988 The nutritive value of five browse legumes fed as supplements to goats offered a basal rice straw diet. MSci Thesis. University of Queensland. Armidale

Sánchez  M D  2000  Mulberry: an exceptional forage available almost worldwide. http://www.fao.org/docrep/x3770t/x3770t05.htm

Shayo  C M 1997  Uses, yield and nutritive value of mulberry (Morus alba) trees for ruminants in the semi-arid areas of central Tanzania. Tropical Grasslands, 31, 599-604.

Singh  R V 1995  Fodder production from tropical forsts in Asia and the Pacific Region. FAO Regional Office for Asia and the Pacific Publicatio 1995/16. Bangkok pp 65

Sorn San and Muirden April  2002 Survey of the Distribution, Management, Marketing and Constraints of Goat Production in Cambodia. Goat Project report for ILRI IFAD TAG 433

Stevens  D R,  Casey M J,  Baxter G S and  Miller K B  1993 A response of Angoratype goats to increases of legume and chicory content in mixed pastures. Proc. XVII Int. Grassl. Cong. P 1300-1301. Palmerston North, New Zealand, Hamilton, New Zealand, Lincoln, New Zealand, February, 13-16, 1993, Keeling & Mundy (1993) Ltd, Palmerston North, New Zealand.

Tichit  L 1981 L’Agriculture au Cambodge. Agence de Cooperation Culturelle et Technique. Paris.

Tran Quoc Viet 1997 Jackfruit and Gliricidia sepium leaves as sole feeds on intake, growth and rumen environment in growing goats. In: Proceedings Regional Seminar-Workshop on Better use of locally available feed resources in sustainable livestock-based agricultural systems in SE Asia (Editors: T R Preston and Kenji Sato). FAO Project GCP/RAS/143/JPn; Ho Chi Minh City (pp: 82-84)

Trujillo F U 2002 Mulberry for Rearing Dairy Heifers. http://www.fao.org/WAICENT/FAOINFO/AGRICULT/AGA/AGAP/FRG/MULBERRY/Posters/Html/Uribe.htm

Van Eys J E, Mathius  I W, Pongsapan  P and Johnson  W L  1986  Foliage of the tree legumes gliricidia, leucaena and sesbania as a supplement to napier grass for growing goats. Journal of Agricultural Science 107:227-233

Wanapat M, Pimpa O, Petlum A and Boontao U  1997 Cassava hay: A new strategic feed for ruminants during the dry season. . Livestock Research for Rural Development 9(2):  http://www.cipav.org.co/lrrd/lrrd9/2/metha92.htm

 

Received  1 June 2003; Accepted 30 July 2003

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