performance of growing goats fed gliricidia maculata
TRANSCRIPT
Performance of growing goats fed Gliricidia maculata
Nguyen van Haoa,b,*, Inger Ledinb
aDepartment of Animal Nutrition, University of Agriculture and Forestry, Thu Duc, Ho Chi Minh City, Viet NambDepartment of Animal Nutrition and Management, Swedish University of Agricultural Sciences, Box 7024, 750 07 Uppsala, Sweden
Accepted 29 May 2000
Abstract
Sixteen female crossbred (local� Anglo-Nubian) goats raised from 20±30 kg were fed a basal diet of cassava chips, cotton
seed cake, rice bran and rice straw, where 0, 30, 40 or 50% of the diet dry matter was replaced with leaves from Gliricidia
maculata. All the diets containing Gliricidia resulted in a higher intake than the diet without Gliricidia, but the diet with 30%
Gliricidia gave the best intake and the highest growth rate, 105 g per day. Total intake was 2.8% of the body weight (BW).
Five male goats of the same breed and size were used to study the effect of supplementing rice straw with different levels of
Gliricidia leaves on intake and apparent digestibility of the diets. Increasing the amount of Gliricidia leaves decreased the rice
straw intake but increased intake of total dry matter (DM), organic matter (OM), neutral detergent ®bre (NDF), acid detergent
®bre (ADF) and crude protein (CP). Supplementing with Gliricidia leaves improved the dry matter digestibility (DMD), the
OM digestibility and the CP digestibility in the mixed Gliricidia and rice straw diet, compared to pure rice straw, but the
values were somewhat lower than could be expected by calculations from the pure rice straw and Gliricidia diets. The DMD of
Gliricidia was 64.1%. # 2001 Elsevier Science B.V. All rights reserved.
Keywords: Goats; Cassava; Rice straw; Gliricidia; Growth; Intake; Digestibility
1. Introduction
In the tropical wet zone of south east Asia, most of
the arable land has been utilised for high value food
crops and industrial crop production (Chen et al.,
1991). The ruminant livestock production in these
areas plays a complementary role in utilising the
by-products of crops and getting some income from
land unsuited to crop production. The ®brous crop by-
products are the major potential feed resources, and
the by-products from rice are most abundant, followed
by those from cassava, maize, cotton seed and banana.
However, the ®brous crop by-products are charac-
terised by extensive ligni®cation of the cellulose
and the hemicellulose, and by low levels of protein,
soluble carbohydrates and minerals. As a conse-
quence, the intake and digestibility of these feeds are
not suf®cient to sustain satisfactory levels of produc-
tion. Supplementation with protein, but also with solu-
ble carbohydrates, is very important for obtaining a
good production (Chen et al., 1991). The leaves from
leguminous trees and shrubs are cheap and readily
available sources of protein. One of the possible species
that can be used is Gliricidia maculata. Ella (1988)
reported that the annual dry matter (DM) leaf yield of
Gliricidia was around 23 t/ha.
The chemical composition and nutritive value of
Gliricidia place it among the high quality forages from
tropical areas. NFTA (1987) reported that the evalua-
tions of Gliricidia as an animal feed for beef and dairy
cattle, sheep and goats have shown promising results.
Small Ruminant Research 39 (2001) 113±119
* Corresponding author. Fax: �46-18-672996.
E-mail address: [email protected] (N. van Hao).
0921-4488/01/$ ± see front matter # 2001 Elsevier Science B.V. All rights reserved.
PII: S 0 9 2 1 - 4 4 8 8 ( 0 0 ) 0 0 1 7 7 - 2
The range of nutritive values found, as percent of DM
were according to NFTA (1987) dry matter digest-
ibility (DMD) 48±77%, crude protein (CP) 18±30%,
acid detergent ®bre (ADF) 18±34%, neutral detergent
®bre (NDF) 27±50%, crude ®bre (CF) 13±30%, ether
extract 4±8%, ash 6±10% and calcium 1±2%.
The utilisation of Gliricidia as a fodder for farm
animals has been tested in Central America, Africa
and Asia (Devendra, 1990) and according to Wiersum
and Nitis (1992) and Stewart and Simons (1994)
Gliricidia has the potential to become a major source
of feed for goats and cattle in dry land farming areas.
The objectives of the present experiment were to
evaluate the effect of feeding different levels of Glir-
icidia leaves as a protein source in diets based on
locally available crop by-products on the growth of
goats and to see if the digestibility of rice straw could
be improved by supplementation with Gliricidia.
2. Materials and methods
2.1. Location and climate of the study area
The experiment was conducted at the experimental
farm of the National University in Ho Chi Minh City.
The climate in the area is tropical monsoon, with a dry
season between November and April and a wet season
from May to October with an average of 1600 mm
rainfall. The mean annual temperature is 288C. The
experiment was conducted between April and June
1998, a year when the wet season started very late
(June).
2.2. Experimental animals and feeds
The animals were selected from a ¯ock of goats
raised in a con®nement system. For the growth experi-
ment 16 females, 6 months old (local female� Anglo-
Nubian male; mature weight 35 kg) were selected. In
the digestibility study, 5 male 8 months old goats were
used. All goats weighed between 19 and 21 kg, when
the experiments started. The goats were vaccinated
against foot and mouth disease and treated against
gastrointestinal parasites using Albendazole tablets
before the commencement of the experiment.
Rice straw was harvested at the university farm and
baled in February and March, 1998. The rice straw
was chopped (10±15 cm) before feeding. Fresh leaves
of Gliricidia maculata, from shrubs planted in 1992 at
the university farm, were harvested every day at 6 a.m.
for the growth experiment. The leaves and small twigs
were included in the feed. Cassava chips, rice bran and
cottonseed cake were bought from local feed mills.
2.3. Experimental design
The diets in the growth experiment (90 days) were
calculated using table values for energy (NIAH, 1995)
and a preliminary chemical analysis of the experi-
mental feeds. The animals were fed DM at a level of
3% of their body weight (BW) and energy and protein
to meet the requirements for maintenance and 100 g of
growth per day according to Peacock (1996). The
goats were randomly assigned to four treatments of
four animals. The Gliricidia contents were 0 (control),
30, 40 or 50% of the offered DM. The intention was to
feed the same amount of DM with the same content of
energy and digestible CP in all diets. Since the Glir-
icidia contained around 25% of CP in DM this meant
that the protein sources used could be decreased when
the level of Gliricidia in the DM increased. The actual
amounts and feeds offered are shown in Table 2.
In the digestibility experiment the animals were
allocated to ®ve dietary treatments with different levels
of Gliricidia according to a Latin Square arrangement
(5� 5) (Mead et al., 1986) (Table 3). The digestibility
experiment lasted 17 weeks in total, 2 weeks of
adaptation and ®ve periods consisting of 3 weeks
per period (1 week of adaptation, 1 week of collection
and 1 week for releasing the animals on an open
ground for exercise). During the period of exercise
the animals were fed on the experimental feed stuffs
supplemented with rice bran and cotton seed cake.
2.4. Feeding and management
The goats in the growth experiment were individu-
ally housed and fed. In the digestibility experiment the
animals were kept in simple metabolism cages, that
allowed separation of faeces and urine. The feeding
troughs were divided into sections, making it possible
to feed each feed stuff separately. Drinking water, salt
and mineral lick blocks were available at all times.
The animals were fed twice per day at 08.00 and
14.00 h.
114 N. van Hao, I. Ledin / Small Ruminant Research 39 (2001) 113±119
2.5. Data collection and analyses
The animals in the growth experiment were
weighed when the experiment started and then once
per week always at 07.00 h. The feed consumption
was recorded and the feed refusals were collected
from individual animals and weighed every day in
the morning before feeding. Samples of feeds, rice
straw, rice bran, cotton seed cake and cassava chips
were taken once per week. Since it can be expected
that these feed stuffs were relatively constant in their
composition (the feed stuffs were bought as one lot at
the same time) the samples were pooled to two
samples per month. Samples of Gliricidia leaves were
taken every day and pooled weekly. DM content was,
however, determined daily before feeding. The refu-
sals were collected every day and pooled together to a
weekly sample.
During the collection period of the digestibility
experiment, samples of rice straw were taken once
per week, while samples of Gliricidia leaves were
taken every day and pooled weekly. DM content was,
however, determined daily. Feed refusals were col-
lected from individual animals and weighed every day.
Samples of faeces and urine were collected every
morning (urine into a solution with sulphuric acid),
weighed and kept in a deep freeze. The animals were
weighed before the commencement of the adaptation
period and before feeding on the ®rst and last days of
each collection period.
The feeds and refusals in the growth experiment and
the digestibility study were analysed for ash, organic
matter (OM), nitrogen (N), NDF and ADF. Samples
for the chemical analysis were taken from previously
bulked feed, refusals and faeces and pre-dried at 608Cbefore grinding using a 1 mm screen and a hammer
mill. DM content in the samples was determined by
drying to constant weight at 1058C. N was determined
using the Macro Kjeldahl method (AOAC, 1985). Ash
content was determined by incinerating the samples at
5008C. NDF and ADF were determined using proce-
dures described by Goering and Van Soest (1970).
2.6. Statistical analysis
The data from the experiment was statistically
analysed with a variance analysis using the general
linear model (GLM) of Minitab Software (Minitab,
1998). The following model was used for the growth
experiment:
Yi � m� Ai � ei
where Yi is the growth or feed consumption, m the
overall mean, Ai the effect of diet, and ei random error.
For the digestibility experiment the model below was
used:
Yijk � m� Ai � Bj � Ck � eijk
where Yijk is the dependent variable, m the overall
mean, Ai the effect of diets, Bj the effect of animals, Ck
the effect of periods, and eijk random error.
3. Results
The chemical composition of the feeds used in the
experiments is shown in Table 1. Cassava chips and
rice straw had low contents of CP while Gliricidia
Table 1
Chemical composition of the diet components, means and S.E.
Growth experiment Digestibility experiment
Gliricidia leaves Cotton seed cake Cassava chips Rice bran Rice straw Gliricidia leaves Rice straw
Samples 12 6 6 6 6 5 5
DM (%) 23.0 � 1.0 90.4 � 0.4 90.0 � 0.3 89.0 � 0.2 90.0 � 0.5 22.0 � 0.3 90.0 � 0.5
Percent in DM
Ash 11.3 � 0.7 5.0 � 0.3 1.8 � 0.1 8.3 � 0.1 16.1 � 0.3 11.2 � 0.4 16.0 � 0.3
OM 88.6 � 0.7 95.0 � 0.3 98.0 � 0.1 91.0 � 0.1 83.9 � 0.2 88.7 � 0.4 83.0 � 0.3
CP 24.8 � 0.8 37.0 � 0.5 3.8 � 0.2 16.3 � 0.3 4.0 � 0.4 24.9 � 0.6 4.0 � 0.4
ADF 32.1 � 2.1 30.8 � 1.5 5.5 � 0.3 9.5 � 0.2 51.4 � 0.9 31.6 � 2.3 51.0 � 0.9
NDF 43.5 � 1.8 43.7 � 0.6 7.9 � 0.1 16.0 � 0.3 79.2 � 0.8 43.7 � 0.8 79.0 � 0.9
N. van Hao, I. Ledin / Small Ruminant Research 39 (2001) 113±119 115
leaves, cotton seed cake and rice bran contained high
amounts of CP. Gliricidia, cotton seed cake and rice
straw had a high content of NDF and ADF.
In the growth experiment there were signi®cant
differences among the treatments in the total intake
of DM, OM, CP, ADF and NDF (Table 2). Total DM
intakes were higher for the diets containing Gliricidia.
The total DM intake were highest on the diet contain-
ing 30% Gliricidia. There were, however, no signi®-
cant differences in intake as percent of BW between
goats fed Gliricidia compared to those given no
Gliricidia. The mean intake was 2.83% of BW.
The effects of Gliricidia supply on BW changes are
shown in Table 2. The mean daily gains were highest
in the treatment with 30% Gliricidia, but differences
were not signi®cant (P > 0:05).
In the digestibility experiment (Table 3), supple-
mentation with different levels of Gliricidia leaves to
rice straw resulted in a signi®cant increase of the total
intake of DM. The digestibility of DM and OM was
highest in the diet consisting of 100% Gliricidia, and
Gliricidia supplementation increased (P < 0:05)
apparent CP digestibility compared to the basal rice
straw diet. Calculations of DM and CP digestibility for
the mixed diets based on the intake and digestibility of
straw and Gliricidia, respectively, showed that the
expected values were somewhat higher than the values
actually obtained. The age of the animals, in this
analysis the effect of period, had no in¯uence on
the digestibility values.
All diets with Gliricidia supplementation resulted
in a positive N balance, while the straw gave a
negative N balance (Table 3).
4. Discussion
Gliricidia has a strong, unpleasant odour and it is
reported (Nitis et al., 1991) that cattle may go off feed
when ®rstly introduced to a Gliricidia sepium diet,
Table 2
Growth experiment: amounts of feed offered and ingested, composition of feed intake and BW changes of the goats, means and S.E.
Experimental diets
GL0 GL30 GL40 GL50
Feed offered (g DM per day)
Cotton seed cake 200 60 10 ±
Rice bran 90 ± ± ±
Cassava chips 250 250 250 225
Rice straw 135 163 145 112
Gliricidia ± 202 270 338
Total 675 675 675 675
Feed intake (g DM per day)
Cotton seed cake 158a � 1.5 59b � 0.8 10c � 0.5 ±
Rice bran 90 � 0.8 ± ± ±
Cassava chips 250a � 0.0 250a � 0.0 250a � 0.0 225b � 0.0
Rice straw 108a � 0.5 145b � 1.0 118c � 1.4 95d � 1.0
Gliricidia ± 201a � 1.0 264b � 0.9 301c � 0.5
Total intake (g per day)
DM 604a � 2.6 658b � 0.8 643c � 1.5 622d � 1.3
OM 565a � 2.9 603b � 1.0 588c � 2.7 572d � 1.3
CP 83a � 0.9 91b � 0.6 88c � 1.0 86d � 0.6
ADF 125a � 1.0 172b � 1.0 165c � 0.9 155d � 0.9
NDF 188a � 0.9 249b � 0.6 237c � 1.0 224d � 0.9
Initial weight (kg) 19.4 � 0.3 19.9 � 1.0 19.6 � 0.6 20.3 � 0.7
Final weight (kg) 27.3 � 0.9 28.8 � 0.8 28.1 � 0.4 28.4 � 0.6
LWG (g per day) 88.3 � 8.2 98.6 � 6.9 94.4 � 6.5 90.2 � 7.9
a,b,c,d Different superscripts within rows indicate signi®cant differences, P < 0:05; GL: Gliricidia.
116 N. van Hao, I. Ledin / Small Ruminant Research 39 (2001) 113±119
while goats did not seem to be affected. The odour can
be minimised by wilting, by harvesting the leaves in
the evening and feeding to livestock the next day (Nitis
et al., 1991). The goats in this experiment had been fed
Gliricidia maculata earlier. The animals were adapted
to eating the Gliricidia within the ®rst few days of the
preliminary period and it only took 20±30 min for the
animals to clear most of the feeds, except the rice
straw, from the feeding troughs. The goats on all
dietary treatments readily consumed the feeds, indi-
cating no palatability problems. The goats on the diet
containing no Gliricidia, however, were not able to
consume all the cotton seed cake and the faeces were
very dry and hard. According to Chadhokar and
Kantharaju (1980) Gliricidia maculata was found to
be palatable by both cattle and sheep even when fed in
very large quantities over a long period.
In the digestibility experiment the increasing levels
of Gliricidia resulted in an increase in the total intake
but a depression in intake of the basal rice straw diet.
This was probably due to the substitution effect, as
reported by Chadhokar and Kantharaju (1980), Ash
(1990) and Kimambo et al. (1992). Leng (1987), also
reported that when roughages of low nitrogen con-
centration are given to ruminants, a supplementation
with protein often results in an increase in voluntary
feed intake, caused by increased availability of fer-
mentable nitrogen. Supplementation of straw with
Gliricidia leaves resulted in an increase in the digest-
ibility of DM, OM, and CP in the total diet, which
could be expected. These results are in agreement with
those observed by Mosi and Butterworth (1985) and
McMeniman et al. (1988), who reported an improve-
ment in digestibility when sheep were fed a crop
residue diet supplemented with legume straw and
increasing levels of the legume Trifolium tembense
(Clover). However, the increase of the digestibility of
the diet seemed to be an effect of the higher level of
Gliricidia and the digestibility of the straw DM was
apparently not affected. The level of Gliricidia sup-
plementation did not seem to be important for the
digestibility of CP in spite of the fact that the CP intake
increased signi®cantly. This could be due to the pre-
sence of large quantities of condensed tannins in the
diets with high levels of Gliricidia leaves. This result
agrees with the study of Jones (1979), and Reed et al.
Table 3
Intake, apparent digestibility and nitrogen balance when feeding rice straw (RS) supplemented with Gliricidia leaves (GL) to goats, means and
S.E.
Experimental diets
600 g
RS
420 g
RS� 180 g GL
360 g
RS� 240 g GL
300 g
RS� 300 g GL
600 g
GL
S.E.
Feed intake (g DM per day)
Rice straw 299.1a 247.6b 198.4c 187.5d 0.0e 9.1
Gliricidia 0.0a 168.5b 224.7c 280.6d 507.4e 9.6
Total intake 299.1a 416.1b 423.1b 468.1b 507.4c 13.4
Digestibility (%)
DM 55.5 58.4a,b 59.1a,b 58.2a,b 64.1b 1.5
OM 59.6 61.5a,b 62.1a,b 61.1a,b 66.3b 1.5
CP 3.5a 58.4b 61.3b 63.3b 70.7b 4.4
Digestibility (%) calculated
DM 59.0 60.1 60.7
CP 58.4 62.8 64.2
Nitrogen balance (g per day)
N-intake 1.96d 8.22a 10.21a,b 12.36b 20.32c 0.5
N in faeces 1.89d 3.42a 3.95a,b 4.53b 5.95c 0.2
N in urine 0.90c 3.38a,c 3.86a 4.79a,b 7.21b 0.6
N-balance ÿ0.75a 1.42a 2.39a 3.04a 7.19b 0.9
a,b,c,d,e Different superscripts within rows indicate signi®cant differences, P < 0:05.
N. van Hao, I. Ledin / Small Ruminant Research 39 (2001) 113±119 117
(1990), who reported that fodder tree leaves should
constitute about 30% of the diet, because of the
secondary compounds which inhibit the digestibility
and reduce the acceptability to animals at higher levels
of inclusion. Also Devendra (1993) and Stewart and
Simons (1994) concluded that when used as supple-
ments the optimum dietary level of fodder trees and
shrubs should be about 30±50% of the ration on a DM
basis.
The Gliricidia leaves signi®cantly improved not
only DMD and daily N intake but also N balance
compared to the straw diet in the digestibility experi-
ment. According to Crowder and Chheda (1982), low
protein content in herbage results in low apparent
protein digestibility, and the digestibility approaches
a zero value when CP content declines to around 3%.
Van Soest (1982) reported that apparent digestibility
can be negative in the case where a small intake or low
digestibility is associated with a relatively large meta-
bolic loss of the constituent. All goats were however,
in positive N balance on the diets containing Glirici-
dia, indicating that these rations can meet the N
requirement of the goats. Similar results have been
reported on the intake and digestibility by goats and
sheep when rice straw was supplemented with Glir-
icidia (Richards et al., 1994; Senani et al., 1997;
Srinivasulu et al., 1998).
The CP content should have been enough according
to the requirements for maintenance and 100 g of
growth per day for all the diets (Peacock, 1996).
The goats given Gliricidia had a somewhat higher
daily weight gain than the goats given no Gliricidia,
but the differences were not signi®cant. Since there
were only four animals per treatment, the differences
may have been too small to be signi®cant.
In the digestibility experiment the animals fed only
straw consumed about 2.2 MJ ME per day and the
animals fed pure Gliricidia 5.5 MJ ME per day. This
was below the energy requirements of the animals and
increasing levels of Gliricidia resulted in an increased
proportion of N in the urine, showing that the lack of
energy lead to increased losses of degradable N via the
urine.
According to Van Eys et al. (1986), Nitis et al.
(1991) and érskov (1992), better performance can be
obtained by supplementing the diet with Gliricidia,
and this may be associated with a greater supply of
bypass protein from the Gliricidia leaves. This effect
was not looked into in this experiment. It may be that
the effect of the tannins are optimal at some level and
according to earlier mentioned authors (Jones, 1979;
Reed et al., 1990; Devendra, 1993; Stewart and
Simons, 1994; Devendra and D' Mello, 1995), that
level seems to be around 30% of Gliricidia in the diet
DM, which was also the case in this study.
The use of Gliricidia or leaves from other legumi-
nous feeds gives an opportunity to provide variety in
the diet. Goats prefer to select from a variety of feeds,
such as a combination of grasses, shrubs or tree leaves
and are said not to thrive well when kept on a single
type of feed for any length of time (Devendra and
Burns, 1983). Using tree leaves as a fodder also
decreases the dependency on concentrates. The actual
amount of leaves fed will be a question of the relation
between feed costs and production, a lower production
with a higher level of leaves may give the best pro®t to
the farmer.
5. Conclusions
Replacing 30% of the DM in the diet with Gliricidia
resulted in increased total intake of DM, OM and CP.
There were no signi®cant differences in growth rate
due to level of Gliricidia in the diet. DM digestibility
for straw was 55.5%, and for pure Gliricidia, 64.1%.
Combinations of straw and Gliricidia had intermedi-
ate digestibilities, somewhat lower than calculated
values suggesting that there was no positive interac-
tion between the straw and the Gliricidia. The results
indicated that moderate levels (30±40% of diet DM) of
Gliricidia can be used in diets for growing goats
without any negative effects on intake and perfor-
mance.
Acknowledgements
The authors would like to acknowledge the Swedish
International Development Authority (SIDA) which
sponsored this study. We also thank the Swedish
University of Agricultural Sciences, Department of
Animal Nutrition and Management, Uppsala and
members of the staff of the Animal Nutrition Depart-
ment of the University of Agriculture and Forestry, Ho
Chi Minh City.
118 N. van Hao, I. Ledin / Small Ruminant Research 39 (2001) 113±119
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