PRODUCTION, DEFOLIATION AND STORAGE OF CASSAVA LEAVES AS DRY SEASON FORAGE FOR SMALL RUMINANTS IN SMALLHOLDER CROP - LIVESTOCK PRODUCTION SYSTEM

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AGRICULTURA TROPICA ET SUBTROPICA




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PRODUCTION, DEFOLIATION AND STORAGE OF CASSAVA LEAVES AS DRY
SEASON FORAGE FOR SMALL RUMINANTS IN SMALLHOLDER CROP –
LIVESTOCK PRODUCTION SYSTEM.

FASAE O.A., ADU I.F., AINA A.B.J., ELEMO K.A.


Abstract

Experiments were conducted in 2005 and 2006 cropping seasons in south west Nigeria to investigate the yield per-
formance of cassava (Cultivar TMS 30572) as influenced by defoliation time and the chemical composition of the
leaf obtained when harvested and stored as dry season forage for small ruminants. Five defoliation treatments of 0,
4, 5, 6 and 7 months after planting were arranged in a randomized complete block design with three replicates.
Cassava yielded an average of 925 kg DM/ha of leaves with a corresponding crude protein content of 20%. The
cassava tuber yield was 11 966 kg/ha. Generally, cassava tuber yield was not influenced (P > 0.05) by defoliation
but plants defoliated before 6 months after planting had reduced (P < 0.05) leaf yield. The fiber fractions, neutral
detergent fiber, acid detergent fiber and acid detergent lignin contents as well as the hydrocyanic content of the
leaves increased (P < 0.05) with increase in defoliation time. Storing cassava leaves beyond 3 months increased
(P < 0.05) the DM content, while crude protein content declined (P < 0.05) with the length of storage. The study
showed that with the variety under investigation, defoliation schedules for cassava which are appropriate for qual-
ity forage production involve those made from 6 months after planting without significantly decreasing (P > 0.05)
the crop tuber yield. Storing cassava leaves for 3 months produced leaves of high nutritive value thereby allowing a
continuous supply of feed for smallholder small ruminant production during the dry season.


Key words: forage, cassava, defoliation, storage, small ruminant; South west Nigeria



INTRODUCTION
This study was aimed at producing a dry season feed for

small ruminants thereby establishing the effects of defo-
Cassava is one of the most important staple food crops
liation time on the leaf yield and quality as well as tuber
widely cultivated in the lowland humid tropics. It plays
yield of cassava cultivar Tropical Manihot Specie (TMS
a major role in alleviating the African food crisis be-
30572) which is widely cultivated by most cassava
cause of its efficient production for energy, year round
farmers in Nigeria because of it’s adaptability to the
availability, tolerance to extreme conditions, and suita-
environment and higher tuber yield (Emerole et al.,
bility to present farming and food systems in Africa
2001). The effect of length of storage on the chemical
(IFPRI, 2000). Nigeria is currently the world’s largest
composition of cassava leaf was also evaluated.
producer of cassava crop (IITA, 2005) and over four

fifth of its cultivable land area has been found suitable

for cassava cultivation (Nweke, 1992).
MATERIALS AND METHODS
Cassava leaves have continued to be one of the prima-

ry sources of feed for small ruminant animals through
Experimental site
systematic defoliation (Fasae et al., 2006) and after

tuber harvest (Alli-Balogun et al., 2003; Ngi et al.,
The experiment was conducted at the Teaching and
2006), especially among small holder crop-livestock
Research farms, University of Agriculture, Abeokuta,
farmers who keeps the largest proportion of small
Nigeria. The location is 76 meters above sea level and
ruminants in Nigeria (Lapkini, 2002). Cassava leaves
falls within latitude 7015’N and longitude 3025’E, and
have been found to have high nutrient value which can
situated in the forest transition zone of south western
effectively boost the nutrition of small ruminant pro-
Nigeria. It experiences approximately seven months
duction when preserved as hay, thereby assisting in
(April to October) of rainfall that is bimodal in pattern.
formulating and processing of simple, adoptable and
It receives a mean annual precipitation of 1 037mm,
low cost feed resource strategy for small ruminants
with a mean annual temperature of 34.70C and mean
during the dry season when there is scarcity of forage
relative humidity of 82%. It has about five months (No-
(Wanapat et al., 2000). However, most of these far-
vember to March) of dry season each year, though,
mers are reluctant to defoliate their cassava because of
irregularity may occur in the rainfall distribution pattern
the envisaged possible reduction in tuber yield which
over the year. The field work was conducted on a well
is the primary crop tuber.
drained, deep, sandy/loam soil with pH of 6.5. The

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experiment commenced during the early cropping sea-
at 12 months after planting were obtained by harvesting
son of years 2005 and 2006, respectively.
tubers from each replicate from the four middle rows

and weighed.
Cassava cultivation

Tropical Manihot Species (TMS 30572) cultivar of
Chemical analyses
cassava which is popularly called “Texaco” by farmers
The proximate composition of the defoliated and stored
was planted. Cassava cuttings (20 to 25 cm long) were
leaves was determined by the method of AOAC (1995).
obtained from matured stems and planted as soon as the
The DM was determined by oven drying at 650C to
rains were established in April, 2005 and 2006 for the
constant weight, crude protein (CP) by Kjeldhal method
first and second year planting, respectively. The cassava
and fat by Soxhlet fat extraction method. The concentra-
plot was randomly laid out into five defoliation treat-
tion of neutral detergent fibre (NDF), acid detergent
ments of 0, 4, 5, 6 and 7 months after planting (MAP),
fibre (ADF) and lignin in the leaves were also estimated
arranged in a randomized complete block design with
by the method of Van Soest and Robertson (1994). The
three replicates. Cassava stem cuttings were planted at
hydrocyanic acid (HCN) in feed was assessed as de-
90 × 90 cm spacing. Weeding was carried out manually
scribed by Bradbury et al. (1999).
using West African hoe at 4 and 15 weeks after plant-

ing. Fertilizer was applied at 5 and16 weeks after plant-
Data analysis
ing using a compound NPK (15 : 15 : 15) fertilizer at
Data obtained were based on randomized complete
the rate of the 100 kg/ha.
block design and subjected to analysis of variance using

the statistical package (SAS, 1999). Significant means
Storage process
were separated using Duncan Multiple Range Test
Cassava leaves were defoliated at 6 months after plant-
(Duncan, 1955).
ing (MAP) from the established plot, chopped with a

cutlass and thereafter sun dried for 5 days. While dry-

ing, the leaves were turned at regular intervals and were
RESULTS
then put into bags of 25 kg each. The leaves were stored

for five months in a well ventilated room during which
The results of the study as shown in Table 1 revealed that
chemical changes due to storing were monitored
defoliating cassava at 4 months after planting (MAP) in
monthly.
the two years produced the least (P < 0.05) leaf yield

compared to the other defoliation treatments. Cassava
Data collection
defoliated at 5 MAP and beyond produced significantly
The leaf yield of cassava at various stages of defoliation
higher (P < 0.05) leaf yield in 2005 which were statisti-
was obtained by harvesting half of the leaves on the
cally similar to the control treatment. In 2006, plants
plant from the soil level. Plant height was obtained as
defoliated at 4 and 5MAP and those of the control treat-
height of ten randomly selected plants per plot from the
ment produced lower (P < 0.05) leaf yield than other
middle row at harvest from the soil level to the tip of
periods of defoliation. Defoliating cassava did not affect
each plant. Number of tubers per plant was obtained by
(P > 0.05) plant height of cassava in both years. The fresh
counting the number of tubers per plant at harvest from
tuber yield of cassava across the defoliation treatments
the ten randomly selected tubers. The fresh tuber yield
did not also respond (P > 0.05) to defoliation.





Tab. 1: Effect of defoliation time on leaf yield, plant height, number of tuber per plant and fresh tuber yield of
cassava cultivar TMS 30572 in two planting seasons
Defoliation
Fresh tuber yield
Leaf yield (kg/ha)
Plant height (cm)
Number of tuber/plant
time
(kg/ha)
(Months)
2005
2006
2005
2006
2005
2006
2005
2006
4MPA
737b
808c
182.0
183.7
6.3
7.0
11 353
11 908
5MAP
876ab
969abc
184.0
190.0
6.5
6.8
11 628
11 849
6MAP
971a
1 090a
189.3
191.0
6.4
6.6
11 447
11 979
7MAP
966a
1 043ab
186.7
194.0
6.8
7.1
11 933
12 438
UND
918a
870bc
192.7
198.0
7.0
7.1
12 286
12 842
Mean
894
956
187.3
191.3
6.6
6.9
11 748
12 203
SE±
65.8
66.1
10.6
12.9
0.2
0.3
491.1
368.3
a,b,c Means in the same column with different letter (s) differ significantly at 5% level of probability using DMRT
(Duncan’s multiple range test), MAP Months after planting, UND Undefoliated


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Tab. 2: Effect of cropping year and defoliation time on leaf yield, number of tuber/plant, plant height and fresh
tuber yield of cassava cultivar TMS 30572 in two planting seasons
Leaf yield
Plant height
Number of tu-
Fresh tuber yield
Treatment
(kg/ha)
(cm)
ber/plant
(kg/ha)
Year (Y)




2005
894
187.3
6.6
11 748b
2006
956
191.3
6.9
12 203a
Mean
925
189.3
6.7
11 974
Defoliation time (D)




4 MAP
772.5b
182.8
6.6
11 630b
5 MAP
922.5ab
187.0
6.7
11 738b
6 MAP
1030.5a
190.2
6.5
11 713ab
7 MAP
1004.5a
190.3
6.9
12 185ab
UND
894.0ab
195.3
7.1
12 564a
Mean
924.8
189.1
6.8
11 966
SE±
10.8
3.1
0.8
26.6
Y × D
*
*
ns
*
a,b Means in the same column with different letter(s) differ significantly at 5% level of probability using DMRT
(Duncan’s multiple range test), MAP Months after planting, UND Undefoliated., * Significant at 5% level of pro-
bability, ns Not significant

Tab. 3: Dry matter, crude protein, fiber and hydrocyanic acid compositions of cassava leaves at different defoliation
time in two planting seasons
Defoliation
Neutral deter-
Acid detergent
Acid detergent
Hydrocyanic
Dry matter
Crude protein
time
gent fiber
fiber
lignin
acid
(Months)
2005
2006
2005
2006
2005
2006
2005
2006
2005
2006
2005
2006
4 MAP
90.1b
89.0b
24.5a
26.8a
51.0b
46.9b
30.8b
29.9b
5.5c
5.5b
22.8d
20.9c
5 MAP
90.3b
89.2b
23.4a
24.2ab
51.9b
49.2ab
32.8ab
31.1b
5.8c
6.1ab
25.3cd
22.1c
6 MAP
90.7b
90.8ab
20.5b
22.6bc
52.8b
51.4ab
34.4a
35.1a
6.2bc
6.3a
26.4bc
22.4c
7 MAP
91.6ab
91.3a
18.9c
19.7cd
53.0b
52.9a
35.1a
35.5a
7.6ab
6.8a
32.7a
27.2ab
UND
92.5a
92.0a
16.3d
16.9d
56.3a
54.3a
35.9a
37.1a
8.0a
7.4a
32.7a
29.2a
Mean
91.0
90.5
21.1
22.0
53.0
51.0
33.8
33.7
6.6
6.4
27.3
24.4
SE±
0.6
0.4
0.4
0.5
0.9
0.8
0.6
0.8
0.4
0.3
0.5
0.4
a,b,c, d Means in the same column with different letter(s) differ significantly at 5% level of probability using DMRT
(Duncan’s multiple range test), MAP Months after planting., UND Undefoliated

Tab. 4: Effect of length of storage on the chemical composition (%) of cassava leaves in two planting seasons
Chemical constituents
s

-
t
h
e

n
neutral detergent
acid detergent
acid detergent
hydrocyanic
o
dry matter
crude protein
f

s
t
o
r
a
g
fiber
fiber
lignin
acid
M
o
2005
2006
2005
2006
2005
2006
2005
2006
2005
2006
2005
2006
1
90.7 b
90.9b
20.5a
22.6a
51.1
51.4
34.4
35.1
6.1
6.8
26.4a
22.4a
2
91.1b
90.9b
19.9a
22.1a
51.3
51.9
34.4
35.2
6.2
7.2
25.9a
22.0a
3
91.8b
92.6ab
19.0a
21.9a
51.9
52.2
34.8
35.7
6.2
7.6
25.1ab
20.9b
4
92.8ab
93.3a
18.8ab
19.1b
52.0
52.8
34.9
36.1
6.5
7.8
24.2b
19.7b
5
93.4a
94.1a
18.2b
18.6b
52.7
53.0
35.4
36.2
7.0
7.9
20.9c
18.6bc
Mean
91.9
92.4
19.3
20.9
51.8
52.3
34.9
35.7
6.4
7.5
24.5
20.6
SE±
0.24
0.29
0.08
0.08
0.31
0.42
0.23
0.21
0.03
0.04
0.22
0.17
a,b,c Means in the same column with different letter (s) differ significantly at 5% level of probability using DMRT
(Duncan’s multiple range test)


The results of the combined analyses (Table 2) for leaf
of cropping year by defoliation time on leaf yield plant
yield, plant height and number of tuber per plant across
height and tuber yield was significant (P < 0.05) while
the treatments revealed that the effect of year was not
that of number of tuber per plant was not significant
significant (P > 0.05), while tuber yield differed signifi-
(P > 0.05).
cantly (P < 0.05) across the years. The interaction effect

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Table 3 shows that the effect of defoliation time on the
those of this study might be responsible for the differ-
chemical composition of cassava leaves differed signifi-
ence.
cantly (P < 0.05) across the treatments in both years.
The mean cassava fresh tuber yield of 11.7 t/ha and
Defoliated plants recorded lower (P < 0.05) DM con-
12.1 t/ha, respectively reported in this study for both
tents relative to the control treatment. The CP contents
years at 12 MAP is higher than 10.6 t/ha and 11.9 t/ha
of the leaves decreased (P < 0.05) as the defoliation
reported by Ayoola and Adegbola (2004) for cassava
time increased. Cassava leaves defoliated at 4 months
under the influence of planting patterns and different
after planting (MAP) which ranked the same with those
pruning methods. Nweke (1992) reported higher values
defoliated at 8 MAP had higher (P < 0.05) CP contents
of 14.7 t/ha as the average yield of cassava from none
compared to the other defoliation treatments. The fiber
pruned plots in Nigeria. The variation may be attributed
fractions NDF, ADF and ADL contents of the leaves
to the cultivar used, time of defoliation coupled with the
increased (P < 0.05) with defoliation time. The NDF
cultural practices employed. The higher tuber yield in
contents in the defoliated treatments were lower
the second year of experimentation could be due to the
(P < 0.05) than the control treatment while the hydro-
use of residual nutrient from the previous year fertiliza-
cyanic acid (HCN) content of cassava leaves increased
tion, and the fact that crop residue from the first year
(P < 0.05) with increase in defoliation.
was not removed totally from the field.
The effects of five months of storage on the chemical
The values for number of tuber per plants is higher than
composition of cassava leaves are shown in Table 4.
5.1 to 6.9 reported by Ayoola and Adegbola (2004) for
The results revealed that storing cassava leaves beyond
cassava under the influence of planting patterns and
3 months from the onset of storage increased (P < 0.05)
different pruning methods on tuber yield of cassava
the DM contents while there was a reduction (P < 0.05)
harvested at 12 MAP. The difference could be due to
in the crude protein contents The fiber fractions, NDF,
the cultivar used and management practice employed.
ADF and ADL contents of the stored leaves were not
The variation in the chemical composition of cassava
affected (P > 0.05) by storage period. Storing cassava
leaves at different stages of defoliation is in line with
leaves beyond 3 months significantly reduced (P < 0.05)
the reports of earlier workers that chemical composition
the HCN and across the treatments.
of forages changes with age and stage of development

(Kalu et al., 1985; Babayemi et al., 2002). However, the

increase in the DM content of cassava leaves with in-
DISCUSSION
crease in defoliation time shows an increase in the DM

of forages with increasing stage of maturity. On the
The results of this study revealed that cassava leaves
other hand, the decrease observed in the CP contents of
defoliated from 6 MAP has little or no influence on
the leaves as the week of defoliation increases could be
tuber yield and that cassava foliage could be harvested
as a result of advanced maturity of the plants. This indi-
from 6 MAP to ensure more leaves, high nutrient con-
cates that higher CP could be obtained with plants har-
tent and avoid reduction in tuber yield. This is similar to
vested at a much earlier age as age of harvest influences
the results of a study by Montaldo and Montilla (1977)
the nutrient composition of forages (Wanapat et al.,
on the production of foliage from cassava for use as
1997). The results of the NDF, ADF and ADL contents
protein feed where best results were obtained with suc-
of the cassava leaves that increased significantly as the
cessive removals of foliage after four months of plant-
weeks of defoliation increased show that fibre level
ing. Contrary results were however reported by Singh
increases with age of forage, thereby suggesting that
and Chaudhury (1985) when cassava was defoliated in
rapid lignification with its attendant decreases in nutri-
the second, fourth and sixth months after planting. They
tive value are obtained as the plants matures. The in-
found out that defoliation of cassava at any stage of the
crease in HCN content of cassava leaves with the time
crop was observed to be harmful to the plants. It is rea-
of defoliation shows that HCN content of cassava leaves
sonable to attribute the variation in the above reports to
increases with forage maturity.
environmental conditions and the defoliation pattern
The increase in DM values of the leaves as the storage
employed which might probably have led to reduction
period increases indicate loss in moisture. The decline
in effective photosynthetic activities of the plant.
in CP contents of the leaves as storage length increases
The mean cassava leaf yield of about 1.0 t/ha across the
agrees with the findings of Oladotun et al. (2003) who
defoliation treatments is lower than the range of 1.4 to
observed reduction in these nutrients during feed sto-
2.0 t/ha reported by Ebong et al. (1995) when the effect
rage. At the end of the storage, the CP content of cassa-
of spacing and interval of cutting on the forage value of
va leaves was higher than the level (11 to 12%) required
cassava foliage was assessed. Preston and Rodriguez
for moderate level of ruminant production (Gatenby,
(2004) however, reported higher foliage yield of 2.0 to
2002), thereby suggesting its adequacy for ruminant
3.0 t/ha when cassava was managed as a perennial crop
production. The decline in HCN content of cassava
with repeated harvesting of the foliage at eight week
leaves with the length of storage shows that the HCN
interval. The period, quantity of plants defoliated and
content in cassava leaves can be reduced by sun drying
intervals of defoliation which were not the same with
with long term storage.


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CONCLUSION
GATENBY R.M. (2002): Sheep. Revised edition. Tropi-

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Washingthon D.C. USA. May 2000.
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Received for publication on December 15, 2008
Accepted for publication on January 2009




Corresponding author:


O.A. Fasae
Department of Animal Production and Health
University of Agriculture, P.M.B. 2240
Abeokuta, Ogun State, Nigeria
e-mail: [email protected]

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