Cuadernos avicolas

Transcription

Cuadernos avicolas
Cassava in Poultry Nutrition
Julián Buitrago Arbeláez
Jorge Luis Gil Llanos
Bernardo Ospina Patiño
Latin American and Caribbean Consortium to
Support Cassava Research and Development,
CLAYUCA
1
Cuadernos Avícolas No. 14
Julián Buitrago Arbeláez (jabuitrago@telesat.com.co)
Jorge Luis Gil Llanos (j.l.gil@cgiar.org)
Bernardo Ospina Patiño (b.ospina@cgiar.org)
Latin American and Caribbean Consortium
to Support Cassava Research and Development
CLAYUCA
A.A. 6713, Cali, Colombia
Telefax: (57-2) 445 01 59
Web: http://www.clayuca.org
Original version in spanish
Translated into english by CLAYUCA
Editing - Spanish version: Elizabeth Meek Muñoz
Hugo Aldana Navarrete
Editing - English version: Bernardo Ospina Patiño
Julián Buitrago Arbeláez
Design and Layout (Spanish version): Cristina Galindo Roldán
(English version): Nidia Betancourth Suárez
Photo Credits: CLAYUCA
Hugo Aldana Navarrete
Printing (Spanish version): Papel House Group
(English version): International Center for Tropical Agriculture, CIAT
Cali, Colombia. August, 2002
This document has been translated into English language with support from the
Southern African Roots Research Network (SARRNET)
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Cassava in Poultry Nutrition
CONTENTS
Preface .................................................................................................................................... 4
Acknowledgements ................................................................................................................. 5
Introduction ............................................................................................................................. 6
Agroalimentary developments based on cassava .................................................................... 7
Agronomic considerations for industrial crops ..................................................................... 8
Mechanization in commercial cultivations schemes ............................................................. 9
Management and industrial post-harvest processing .......................................................... 13
Cassava byproducts with potential to be included in poultry feeding ................................. 20
Nutritional contents of the main products derived from the cassava crop ......................... 21
Variation in the nutritional quality of cassava roots and cassava foliage flour................... 23
Inclusion levels of cassava foliage and cassava roots flour in poultry diets ...................... 26
Complementarity of cassava flour and integral soybeans in feeding programs
for poultry .................................................................................................................................28
Broiler feeding ..................................................................................................................... 30
Layers feeding ...................................................................................................................... 34
Results of field experiences ................................................................................................ 36
Conclusions .......................................................................................................................... 41
References ........................................................................................................................... 43
Appendix:
Some manufacturers of cassava production and processing equipments ........................... 44
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Cuadernos Avícolas No. 14
PREFACE
e are convinced at FENAVI that in tropical countries we need to find what
tropical nature has to offer, products, by-products or product associations that
allow us to meet, in a competitive form, the proteins and energy required by
poultry. This competitiveness has to be based in achieving efficiencies and low costs similar
to those obtained in temperate countries.
W
In our Occidental Hemisphere, countries like Brazil, and in the Oriental Hemisphere,
Thailand, show significant improvements in the tropical production of raw materials and
subsequently in the poultry production. We need to learn from them the action and the
aspiration to produce competitively under the maximum possible tropical conditions.
In an extraordinary agronomic synthesis, Dr. Julian Buitrago and his collaborators are
proposing the readers of this Cuaderno Avícola No. 14, the audacious use of cassava in
poultry feeding, under the premise of “tropicalización of the poultry industry”.
We are conscious that the ideas of Dr. Buitrago, in particular, generate some resistance
among the experts and cassava users for poultry feeding. We are conscious that his thesis
are as dared to break paradigms pre-established long time ago among us. We are conscious
as well that only the audacity in this field, the essay, the proof and the mistake, as are here
discussed, can give future space for further development of our second potential resource
in the tropical zone for the technological offer in poultry feeding: the cassava crop.
It is in the reader’s hands the judicious valuation of the thesis presented and the scope of the
work that this document popularizes among the agents involved in the poultry chain. With
our expectation of continuing with strong steps in the challenge of tropicalization of the
poultry industry, we invite you to read this document.
DIEGO MIGUEL SIERRA BOTERO
Executive President-FENAVI
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Cassava in Poultry Nutrition
ACKNOWLEDGEMENTS
he development of this study has required the collaboration of several persons and
institutions. In general, we found great interest and enthusiasm among the people
we contacted to obtain information, to backup field labor or to collect and analyze
the results.
T
Certain that it is impossible to mention all the persons and institutions that participated in
the different phases of the project, we have listed the names of the institutions where the
most important field work took place and those who were most actively involved with the
preparation and publication of the present document:
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International Center for Tropical Agriculture, CIAT
Federación Nacional de Avicultores, FENAVI
Latin American and Caribbean Consortium to Support Cassava Research and
Development-CLAYUCA
Universidad Nacional de Colombia
American Soybean Association, ASA
Corporación Colombia Internacional, CCI
Ministerio de Agricultura y Desarrollo Rural, MADR
Instituto Colombiano Agropecuario, ICA
Concentrados del Norte
Nutrilisto
Avités
Nutribal
Pollos Carioca
Avícola Santa Anita
Avicauca-Agrovélez
Avícola Tuluá
Avícola Santa Rita
Industrias Armare
Procesos Agroindustriales
Industrias Protón
We are very grateful with these institutions and with the rest of collaborators in the other phases of the
work.
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Cuadernos Avícolas No. 14
INTRODUCTION
he following publication consolidates the information about a series of efforts
done by several institutions and persons that have participated in the different
phases of the process of production, processing and use of cassava crop, with the
purpose of obtaining an important nutritional alternative to the livestock sector, in general,
and the poultry, sector in particular. Research activities conducted and promoted by CIAT,
FENAVI, CLAYUCA, ICA and the MADR, are the basis for the majority of the results
analyzed in this paper.
T
Two big issues constitute the basic argument to consider cassava as a strategic input, of
great potential, in the future plans for animal feeding in tropical regions:
- The agronomic, cultural and environmental conditions in many tropical regions, allow a
great potential for the development of large cultivated areas with industrial cassava, with
high yielding varieties in dry matter and energy, that can be used in animal feeding
guaranteeing at the same time the validity of the postulates of agricultural competitiveness
and sustainability.
- The demand for balanced feeds and raw materials for its preparation is increasing
permanently as a result of the rising demand for meat products, eggs and milk in most of
the developing regions. Agriculture in these areas hardly contributes to overcome the
deficit in energetic and protein sources that can compete with the imported cereals for the
fabrication of the required animal balanced feeds.
Considering the nutritional facts of cassava flour from roots and foliage, it is possible to
consider its utilization as a partial or complete substitute of the cereals used in the
production of animal feed rations for poultry and broilers. By introducing the nutritional
adjustments needed in the feed rations that contain cassava roots and cassava leaves flour,
animal performance can be perfectly comparable with that obtained using balanced feeds
based on cereals.
Considering the importance of this topic, the present document analyzes, in a very general
form, various important aspects in the fields of industrialization and processing and, in a
more detailed way, the animal nutrition concepts applicable to the poultry industry.
6
Cassava in Poultry Nutrition
AGROALIMENTARY DEVELOPMENTS
BASED ON CASSAVA
T
he cassava crop can be oriented
towards various applications in
the fields of feeding and
industrialization. Humans generally
consume cassava in its fresh form but the
roots can also be used in different post
harvest processes to elaborate products
with added value or to obtain other
agroindustrial inputs of great demand in
the internal and external markets
(starches, glues, sodium glutamate,
dextrines, alcohol, modified starches,
etc.).
When the possibility offered by the
cassava crop to be used in animal feeding
is analyzed, it is important to consider
that, besides roots, the aerial part or
foliage represents an element of a great
nutritional potential as a source of protein
and natural pigments.
Figure 1 presents a general scheme in
which the different routes of utilization of
the cassava crop, with greater emphasis in
those oriented to animal feeding, are
illustrated.
Despite the fact that the objective of the
present publication is focused towards the
use of cassava in animal feeding, it is
necessary to recognize that any industrial
successful development in production and
marketing of cassava should be based in
complementary criteria to the utilization
of the different products that can be
generated in the transformation chain: a
part of the fresh cassava roots, with the
best culinary quality can be destined to
direct human consumption where
normally the best prices are obtained; the
other part can be included in the fresh
products market, with primary processing,
such us frozen cassava chips or paraffin
coated cassava roots. Other more
complete processes that can be done are
the production of cassava croquettes
enriched with vegetable or animal
proteins.
When the roots are not suitable for
human consumption, or when this market
is not attractive because of low prices or
little demand, a good possibility is the
elaboration of products for industrial use
(starches, dextrines, modified starches,
etc.), or the production of cassava flour
to penetrate the big animal feeding
market.
The adequate balance between these
potential markets for cassava constitutes
the main strength for the development of
industrial production schemes to take
advantage, in an efficient way, of the
differential advantages that the cassava
crop has to offer in regions where other
agricultural crops can hardly prosper.
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Cuadernos Avícolas No. 14
Figure 1. General scheme for the processing and
utilization of cassava products and by-products.
Fresh
cassava
roots
Human
consumption
Industry
starch
glue
modified starch
Animal
feeding
Fresh
roots
Fresh
cassava
leaves
Natural or artificial
dehydration
Dried roots for
animal feeding
By-products for
animal feeding
Dried leaves for
animal feeding
Ensiled
roots
Animal
feeding
AGRONOMIC
CONSIDERATIONS FOR
INDUSTRIAL CROPS
There is a lot of information available about
the agronomic practices recommended for
the multiple uses of cassava in human
consumption. There are also
recommendations about varieties and quality
characteristics for cooking applications.
The objective of obtaining high yields of
usable dry matter (digestible metabolizable
energy) and optimizing other productivity
parameters, with less emphasis on cooking
characteristics (color, flavor, texture), has
facilitated the development of varieties with
8
high yields per hectare of roots or foliage,
and with a high potential for the animal
feed industry.
Although high yielding varieties can
contain a high level of cianogenic acid, that
anti-nutritional principle can be controlled
by means of an adequate processing, which
eliminates any possibility of affecting the
animal’s behavior.
When the introduction of high yielding
varieties is combined with appropriate
cultural practices, there is always the
possibility to obtain high yields in terms of
products for use in animal feeding. Under
conditions of commercial cultivation it is
possible to obtain production levels of 25 to
Cassava in Poultry Nutrition
40 tons of fresh roots (9.5 to 15 tons of
dry roots) and between 5 to 10 tons of
fresh foliage (1 to 2 tons of dry foliage)
per hectare. This productivity levels are
almost impossible to obtain in tropical
environments with other agricultural
crops of direct application in animal
feeding.
MECHANIZATION IN
COMMERCIAL
CULTIVATION SCHEMES
The approach of incorporating cassava
production as an important alternative in
the elaboration of animal balanced feeds
involves, as much as possible, the
implementation of modern production
techniques, in the different stages of the
production chain: cultivation, harvesting,
transportation, processing, storage and
utilization.
Besides the incorporation of high
yielding varieties, the concept of
industrial production includes the
planting in production units that are
profitable and adequate for the introduction
of mechanization practices both in the
cultivation and in the processing of the
final products.
Mechanization (with the subsequent
reduction in production costs) can be
applied specially in three phases of the
process: during the planting, during the
harvesting of roots and foliage and during
the post harvest process to obtain cassava
roots and foliage flour.
Some of the most important aspects of the
mechanization process for cassava planting
and harvest operations are:
Mechanized planting
In recent years, important progress has been
made in the development and adaptation of
efficient equipment for mechanized planting
of cassava, especially through the application
of technology developed in Brazil. Although
Figure 2. Aspects of Industrial Production Schemes.
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Cuadernos Avícolas No. 14
Figure 3. Equipment for
mechanized planting of cassava
(two and three rows)
the incorporation of these equipments in
cassava industrial cultivation schemes is
not yet a common practice, the results
obtained during the demonstrations made in
different regions, are giving a good evidence of the potential of this practice to
reduce costs and increase the efficiency
and profitability of the crop.
For example, a Brazilian company named
Planticenter has developed prototypes for
mechanized planting that allow the planting
of 7 to 8 hectares per day with the 2 row
model. There are also some models
available for planting 3 rows
simultaneously (Figure 3). The principal
characteristics of these equipments
include:
• Hydraulic lifting
• Seeds cutting through circular sieves
10
•
•
•
•
•
•
acccionated by the power device of the
tractor
Variable planting distances (55 to 90
cmts)
Variable distances between rows (90 to
120 cmts)
Seeds of irregular size are eliminated
Two devices for mechanized application
of fertilizer, with capacity of 70 kg
each one
Ridging soil device based on twin
concave disks
Control device for the depth of the
planting
Mechanized harvesting of cassava roots
For the harvesting of cassava roots, there
are also equipments available, perfectly
tested under commercial conditions that
allow reduction in the labor required per
Cassava in Poultry Nutrition
hectare and the harvesting costs. The
principal characteristics of these
equipments include:
• Attachment to the tractor through the
power device
• Cutting disk for the weeds and residues
• Device for softening the soil on both
sides of the harvested row
• Harvesting device with nail in the rigid
system and spring device in the flexible
system
Table 1 presents the information related to
the performance of the harvesting
operation per person, when the two
methods are compared, the traditional
manual harvesting system with the methods
of mechanized harvesting, using the 2
prototypes mentioned previously. The
yields are based in a planting density of
10.000 plants per hectare and a yield of
12.5 tons of roots per hectare (Figure 4).
Figure 4. Prototypes for cassava roots harvesting.
(Rigid and flexible).
a) Rigid model
b) Flexible model
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Cuadernos Avícolas No. 14
Table 1. Comparison between yields per person with the manual and
mechanical harvesting systems.
Harvesting
method
Plants
harvested
Number of
workers
Hours
worked
Tons/man
per day
Manual
60
1
2.5
0.240
Rigid model
60
1
0.5
1.195
Flexible model
60
1
0.6
0.991
Mechanized harvesting of
cassava foliage
The economic feasibility in the
implementation of intensive cassava foliage
production systems, depends to a laryer
extent in the possibility of maintaining the
labour costs as low as possible, especially
in relation to the harvesting operations.
Important developments have also been
obtained in the development and adaptation
of equipment to collect the foliage of the
cassava crop.
One option is to use a machine operated by
one person to cut the foliage which is later
chopped using a mechanical cutter. (Figure 5)
Recently, CLAYUCA has been working
with a Brazilian company to develop one
prototype. The equipment works attached
to the tractor and makes the cut at the
superior third of the plant, using a device
of 4 disks in a row. This equipment is
useful in large-scale plantation although it
has the inconvenience that the harvested
Figure 5. Manual harvester and
cutter of cassava foliage.
Figure 6. Mechanical harvesting of
cassava leaves and stem.
12
Cassava in Poultry Nutrition
Figure 7. Mechanical harvesting of cassava leaves and stem.
The cassava foliage is cut, chopped and deposited a track.
foliage remains above the soil and has to
be collected (Figure 6).
input for animal feeding in the form of
flour, chips or pellets.
Other recent development in this field has
been the development of a prototype that
can be used to harvest the leaves of the
cassava plant (new and old plants), cut them
into small pieces and send them into a
truck or a collecting device (Figure 7).
MANAGEMENT AND
INDUSTRIAL POST-HARVEST
PROCESSING
The basic aspect in every industrial type
scheme refers to the implementation of
mechanized practices, fast and with the
maximum efficiency, in order to guarantee
an important reduction in production costs
per ton of the final product. Raw materials
usually consist of products with high
volume and humidity (roots and foliage),
which demand the introduction of low cost
transportation systems, bulk handling and
continuous type processes.
This section discusses some aspects
related to transportation, processing and
management of the harvested roots and
foliage, until its final presentation as an
After the roots and foliage have been
harvested it is important to transport them
to the processing, unit as quick as possible,
using high efficiency transportation
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Cuadernos Avícolas No. 14
methods (trucks, or vehicles conditioned
for the mobilization of bulky products).
One of the most important considerations
during the planning process of the
industrial production system refers to the
convenience of locating the point of
collection and processing of the roots as
near as possible to the crop production
areas. It is necessary to take into account
that when roots and foliage are
transported in its fresh form, these
products have more around 65% of
humidity, a factor that has a severe impact
on transportation and industrial
management costs.
The information presented in this section
refers only to the methods used currently
to obtain cassava roots and foliage flour
that can be used as raw material for
poultry diets. The most important steps
include the processes of cleaning,
chipping, dehydration, milling and/or
pelletizing.
Although there is plenty of information
available about these processes, in
separated form, the development of
continuous processing systems, in large
scale, integrated and with great efficiency
is still missing, especially in relation with
the dehydration of the raw material.
Principal methods for dehydration
of cassava roots and foliage
Although numerous dehydration systems
have been developed for other agricultural
crops, in the case of cassava, very little
14
experiences are known related to
important industrial experiences different
than the dehydration methods through solar
energy or mechanical methods of forced
heat based on electric power, steam or
fossil fuels (gas, ACPM, etc.).
Considering the high humidity percentage
that needs to be extracted from the cassava
roots or foliage, it is very important to
select a dehydration method that can
operate with a minimum processing cost,
so that the final cost to obtain one unit of
dry product is reasonable. It is important to
remember that to obtain a ton of cassava
dry chips it is required to have 2.5 to 3
tons of fresh cassava roots, and to obtain a
ton of dry foliage it is required to have 4 to
5 tons of fresh foliage.
The dehydration system based on the use
of solar energy has the advantage of
eliminating the fuel costs. However, there
are many additional limiting factors that
have a very important specific effect on
the total processing costs. The
construction costs for the drying floors is
high, the low efficiency per unit of drying
surface, the high labor demand, the
unpredictable environmental factors (sun,
rain, wind) and the risk that exists of
sanitary contamination in natural
dehydrated products. These factors,
associated with other variables, especially
in large scale production schemes,
indicate that the option of solar energy
processing is only recommended in small
scale extensions or when, for different
reasons, the implementation of
mechanical systems of artificial
processing is not feasible.
Cassava in Poultry Nutrition
Figure 8. Sun drying of cassava
chips on a cement floor.
that to obtain a ton of dry cassava chips,
around 250 m2 of drying surface are
required during one or two days. With load
densities lower than 10 kg/m2, high
environmental temperatures, low
environment humidity and higher wind
velocity, the natural drying process is
accelerated.
The factors that are most influential in the
efficiency of solar drying of cassava roots
are as follows:
Dehydration with solar energy
The most rudimentary method to dry the
cassava roots consists in spreading the
fragments, pieces or chips over a flat
surface (better in cement or asphalt
floors), as illustrated in Figure 8, to expose
them to the action of solar rays and wind.
The moisture content is extracted by
evaporation to obtain a final product with
less than 15% of humidity.
In order to accelerate the process, the
cassava chips must be moved and mixed
regularly, at least every two hours during
the first day, and three or four times the
second day, using a wood rake device.
The density of the load (amount of chips
per unit of drying surface) depends on the
environmental conditions; it has been
estimated that it should not exceed
10 kg/m2, to obtain an efficient drying in
two or three days. This load density means
• Geometry of the chips: the speed of
drying by solar exposure is directly related
to the total surface of the pieces. The drying
time could be shorter when the fragments
are regular and allow a free circulation of air
between them. Rectangular and cubic forms
are the best for a quick and uniform drying.
• Load per unit of drying surface: the
quantity of cassava chips per unit of surface
affects the drying speed. Generally,
densities higher than 10 kg/m2 are not
recommended to obtain an adequate
dehydration in one or two days, provided
that the environmental conditions are
favourable.
• Air conditions: the most influent
variables on the drying speed are the
velocity, temperature and humidity of the
surrounding air. At the initial stages of
drying, cassava pieces loose humidity
faster, therefore the velocity of air is more
important than temperature and humidity.
During the final stage, when the humidity
level is lower than 30%, the dehydration of
the pieces is very slow and high
temperatures are needed to eliminate
15
Cuadernos Avícolas No. 14
residual water. In the natural drying system,
the environmental humidity level is
particularly important during the initial
stage of the process. A relative humidity
level higher than 65% can extend the
natural drying process.
• Initial moisture content of cassava: the
initial moisture content of the cassava
chips determines the amount of water that
must be extracted and, therefore, the speed
of the operation. Likewise, the conversion
factor (amount of fresh cassava required to
produce a unit of dry cassava) changes in
direct proportion to the initial humidity
(Table 2).
In Table 3 it is possible to observe the
effect of the variation of environmental
conditions on the drying time of cassava
chips using cement drying floors with a
high load density (5 kg/m2).
Table 2. Effect of the initial
moisture content of the cassava
roots on the conversion factor.
Initial
humidity
% (a)
Dry cassava per
kilo of fresh
cassava, grams (b)
Conversion
Factor (c)
75
70
65
60
55
280
335
390
445
500
3.6
3.0
2.6
2.2
2.0
(a) Numbers in humid base
(b) Dry cassava quantity with a humidity of
up to 10%
(c) Fresh cassava units required to obtain a
unit of dry cassava
equipment and processing. The correct
choice of the equipment depends on
various factors, specially related to the
fuel costs or the heat source and the
amount of material to dehydrate.
Artificial dehydration methods
There are different systems to achieve the
dehydration of cassava roots with industrial
Considering the high percentage of water
that must be eliminated during the process
and the relatively low market price of the
Table 3. Effect of the environmental conditions on the
drying velocity of cassava root pieces *
Environmental conditions
Temperature
o
C
Relative
humidity
Wind
velocity (m/seg)
Solar radiation
Cal/cm2.min
Drying hours:
in cement
courts
24
70
1.9
0.73
11
26
67
0.8
0.58
17
26
66
1.2
0.61
15
30
64
0.9
0.65
10
31
68
1.0
0.71
13
* Cement floor with a charge density of 5kg/m2.
From: Best and Gómez, 1982.
16
Cassava in Poultry Nutrition
final product (cassava flour or cassava
chips), in order to compete with other
traditional sources of energy, the
dehydration costs are a very sensible
parameter.
For this reason, the use of low cost fuels
and the efficiency of the process are
important factors in the selection of the
dehydration system. A general analysis of
formulation costs for balanced feeds
indicates that the total processing cost
should not exceed 10 to 15%, related to
the final price of the dehydrated product
(i.e. if the market price for cassava flour is
US$150 per ton, the processing cost
should not exceed US$ 15 to 22 per ton of
dry cassava or US$ 5.75 to 8 per ton of
fresh cassava). This processing cost can be
achieved with industrial methods such us
those based on automatic processes and
great volumes schemes. In the process of
dehydration with solar energy it is more
complicated to achieve permanently
processing costs similar to those
mentioned above due to the participation of
many variables that cannot be easily
controlled (solar radiation, rain, drying
area, labour, etc.).
A few companies in Colombia have been
working during the last years in the
development of industrial equipment for
dehydration. The most recent experiences
have showed satisfactory results. Currently,
five companies are known for their
experiences: Armare (Barranquilla),
Industrias Protón (Bogotá), Procesos
Agroindustriales (Cali/Buga), Soyagro
(Barranquilla) and Muskus (Medellín).
These companies base their dehydration
processes on the use of gas or steam.
The initial and final stages of dehydration
are similar in all models and are based in
the following basic elements:
• Reception of raw material (bulk form)
• Roots cleaning and washing (optional)
• Root shipping and grating
• Initial drying process with of controlled
heat to reduce the cianogenic acid level of
the cassava roots
• Final continuous dehydration process
• Reception and packaging
The main differences between the
equipments are the dehydration system and
the type of fuel used, which are reflected in
the final processing costs.
In the Figures 9, 10, 11 and 12, the basic
aspects of these equipments are illustrated.
A more detailed information of each
equipment and process can be obtained
contacting directly the manufacturing
companies whose addresses are in the
Annex at the end of the present document.
In some specific circumstances it is also
possible to assemble a mixed or
combined dehydration system in which
the first part of the drying process is done
using solar energy and the final drying is
conducted using artificial methods. This
combination allows a very significant
reduction in investment and processing
costs although it requires very favourable
climatic conditions for the natural
dehydration process.
17
Cuadernos Avícolas No. 14
Figure 9. Armare* model for cassava
drying and toasting with natural gas.
Figure 10. Protón* model
for cassava drying with gas
and steam.
Figure 11. Agroindustrials*
model for cassava drying with
natural gas.
18
Figure 12. Flow chart of a typical system to dry and roast
cassava chips (Armare company).
12
14
7
1
10
2
8
13
14
4
6
321
321
321
321
321
3
9
11
16
5
15
Engineering
Department
Barranquilla, Colombia
Cassava in Poultry Nutrition
19
1 = transport; 2 = washer; 3 = cassava chipper; 4 = transport belt; 5 = Turbine; 6 = fluidized dryer;
7 = lifter; 8 = fluidized drum dryer; 9 = precooking dryer and release control gate; 10 = turbine;
11 = cyclon; 12 = transport and neumatic cooler; 13 = storage silo; 14 = cyclon; 15 = packaging devier;
16 = neumatic gate.
Cuadernos Avícolas No. 14
CASSAVA BYPRODUCTS
WITH POTENTIAL TO BE
INCLUDED IN POULTRY
FEEDING
The principal resource offered by cassava
for animal feeding is located in the roots,
in its starch form. Normally, the dry
matter content varies between 34 and
38%, with a starch concentration of 75 to
80%. If the reference is the production of
25 tons of fresh roots per hectare, the net
yielding in dry matter and starch is 9.5 and
7 tons, respectively. A small percentage
of the dry matter is represented by protein
(less than 3.0%) and fibre (less than
4.0%).
The aerial part (stems, petioles and
leaves) of the cassava plant constitutes an
additional source of nutrients for the
cattle and poultry sectors. Although the
high contents of fibre limits the use of
cassava foliage flour in poultry, its high
protein and xanthophylls concentration
(natural pigments) represents a great
resource when it is incorporated in the
balanced feed diets in adequate levels.
Normally, the cassava crop cultivation is
orientated towards obtaining roots during
a growing period that oscillates between 8
and 12 months, depending on varieties and
environmental conditions. When the roots
are being harvested, it is also possible to
harvest the useful part of the foliage
(superior third) for its immediate
processing. In this conventional scheme,
foliage yields may fluctuate between 10
to 20% in relation with the roots yield,
20
which also depends on varieties, weather
and crop management (plantation density).
However, it also exists the possibility to
orientate cassava crop towards the
exclusive production of foliage, or towards
the development of a combined program:
crops for the production of roots and crops
for the production of foliage.
In the case of exclusive production of
foliage, the agronomic practices of the crop
have substantial variations, because in this
modality, foliage harvesting must be made
every 2 or 3 months during 1 or 2 years. In
these conditions, it is possible to obtain a
product of better nutritional quality and with
greater yields of green material (up to 40
tons per cut). It is also important in this
modality to have reinforcement through
irrigation and fertilization practices.
CLAYUCA has conducted some studies to
evaluate the feasibilite of intensive
production systems for cassava foliage.
Table 4 includes information about
foliage yielding in three different regions
of Colombia (Buga, Caicedonia and
Ayapel). This preliminary study
(CLAYUCA, 2001) compared the effect
of different planting densities (112.000,
62.500 y 40.000 plants per hectare) and
periodical cuts (every 3 and 6 months at
Buga and Caicedonia).
The numbers cited correspond to
preliminary results of a long-term study.
The yield of green material obtained until
now have been lower than those obtained
in other countries where it has been
possible to harvest up to 40 tons per cut.
Cassava in Poultry Nutrition
Table 4. Yields of intensive cassava leaves production plots
in tons per hectare (fresh weight).
112.000 plants per hectare
Cutting time
(months)
3
6
9
62.500 plants per hectare
40.000 plants per hectare
12
18
3
6
9
12
18
3
6
9
12
18
7.5
12.63
2.27
13.17
6.7
3.37
6.45
3.68
14.03
6.33
3.38
4.56
Buga:
MCOL
15015
3.23
10.93 12.79
MCOL
2758
5.58
16.10 12.99 10.02
8.95
5.05
13.70
8.13
5.68
6.97
5.20
23.23
7.13
5.75
4.6
CM 523-7
4.60
13.77 14.12
9.44
12.37
2.60
13.50
8.22
2.93
8.0
6.15
17.23
3.39
2.10
4.89
15.80 18.76 10.16
13.36 18.17 6.46
6.24
5.33
18.3 8.58 13.15
12.37 11.96 16.20
5.43
7.79
3.14
2.94
7.27
10.3
6.99
7.14
12.88
10.60
5.19
5.54
3.12
3.01
4.18
5.49
16.73 22.94 11.65
5.13
11.06 12.19 18.34
3.13
2.74
8.82
9.12
14.05
8.07
2.81
7.28
-
8.00
7.20
5.60
-
10.16
8.6
14.76
3.18
7.08
3.9
-
Caicedonia:
MPER 183
HMC 1
MCOL
2737
Ayapel:
MTAI 8
CM 4918-1
CM 4843-1
21.70
10.60
24.50
-
27.31 18.09
15.87 6.44
27.20 34.96
-
11.90
9.40
12.20
-
11.63 7.76
12.13 5.94
19.81 15.85
From: Rosero, 2001. Non published data. Evaluation, production and quality of foliage in production
systems of cassava (Manihot esculenta Crantz), with manual periodical cuttings. (CLAYUCA)
NUTRITIONAL CONTENT
OF THE MAIN PRODUCTS
DERIVED FROM THE
CASSAVA CROP
main nutritional contents for products,
roots and foliage, in its fresh form, just
after being harvested. The next two columns
illustrate the information about the products
in the dried form (with 12-14% of
humidity).
Main nutrients
Table 5 illustrates the nutritional contents of
cassava roots and foliage from industrial
varieties produced under good management
conditions. In the case of roots, we are
referring to the integral product (with
peels), and with minimum contamination
from sand, soil or other residual products.
The foliage analysis corresponds to the
superior third of the plant (leaves, petioles
and secondary stems), harvested
simultaneously at the time of harvesting the
roots. The first two columns include the
Table 6 is included with the purpose of
appreciating better the most important
nutritional values of the cassava
by-products, in comparison with other
ingredients of common or potential use in
animal feeding.
As it has been mentioned before, while
cassava roots are characterised by its high
content of energy and its low concentration
of protein and fatty acids, cassava foliage
offers a high level of protein and fibre and a
low energy concentration.
21
Cuadernos Avícolas No. 14
Table 5. Main nutrient contents in cassava roots and foliage, %
Nutrients
Humidity
Metabolizable
Energy*
Protein
Fiber
Fat
Ash
Methionine
Cystine
Lysine
Tryptophane
Threonine
Calcium
Phosphorus
Potasium
Fresh products
Roots
Foliage
65.000
72.000
Dry products
Roots
Foliage
12 to 14
12 to 14
1.200
0.340
3 to 3.1
1.380
1.100
1.200
0.470
1.120
0.010
0.008
0.020
6.500
4.700
1.800
1.700
0.070
0.040
0.370
0.050
0.270
0.520
0.090
0.340
2.800
3.200
1.200
2.900
0.030
0.020
0.060
21.000
15.000
5.900
5.600
0.280
0.160
1.600
0.200
1.170
1.700
0.260
1.200
0.010
0.100
0.150
0.250
0.030
0.300
0.400
0.650
* Mcal/kg
From: Buitrago, 1990.
Table 6. Concentration of metabolizable energy and protein in various
products used in animal feeding.
Product
Fresh cassava root
Dry cassava root (flour)
Fresh cassava foliage
Dry cassava foliage
Fresh sweet potato
Dry sweet potato (flour)
Fresh banana
Dry banana (flour)
Corn
Sorghum
Rice
Integral soybean
From: Buitrago, 1990.
22
Dry Matter
%
Metabolic
Energy
Mcal/kg
Protein
g/kg
35.0
90.0
28.0
90.0
28.0
90.0
20.0
90.0
90.0
90.0
90.0
90.0
1.20
3.05
0.34
1.40
1.03
3.02
0.65
2.85
3.40
3.25
3.15
3.65
12
28
65
210
17
56
10
42
82
88
80
380
Cassava in Poultry Nutrition
Considering that under the traditional
scheme, the crop is oriented towards the
production of roots, the fundamental
element of harvesting is represented in
starches, which generate an important level
of useful (metabolizable) energy for
poultry. The production of foliage is
secondary in this scheme, although it is
possible to obtain important yields of
protein to cover part of the protein
deficiency of the root. In one hectare of
harvested cassava, with a yield of 25 tons of
roots, it is possible to obtain around 28
million kilocalories (metabolizable energy)
from the roots and more than 200 kg of
protein from the foliage.
Anti-nutritional factors
Cassava roots and foliage contain variable
quantities of the glucosides linamarin and
lotaustralin, which, when hydrolysed by the
action of the enzyme linamarase, generate
the free cianogenic acid that can cause
toxicity in the animal organism when it is
higher than the security levels.
(linamarase)
Linamarin + water
cianogenic acid
+ acetone
+ glucose
The total cianogenic glucosides or
cianogenic acid in the cassava root or
foliage determines the difference between
bitter varieties (with greater toxicity) and
sweet varieties. Although there is not a
precise measurement, the varieties
considered as bitter are those with a
cianogenic acid content superior to 100
mg/kg (100 ppm) for fresh product and the
sweet ones have lower levels.
In sweet varieties, the greater proportion of
cianogenic acid can be found in the peel,
while in bitter varieties the acid is
distributed evenly in the peel and the
parenchyma.
Processing methods to eliminate
the cianogenic acid in cassava
The most effective commercial method to
eliminate partially or totally the cianogenic
acid content of cassava is based on the
controlled action of heat. Temperatures
between 40 and 80oC are effective to
eliminate the largest portion of the free
cianogenic acid. The natural dehydration
with solar rays is also a secure system to
destroy the cianogenic acid without
affecting the action of the linamarase
enzyme. The industrial processes of
dehydration using heat are also effective, as
long as the temperature control
corresponds with the temperature ranges
required for the detoxification process.
VARIATION IN THE
NUTRITIONAL QUALITY OF
CASSAVA ROOTS AND
CASSAVA FOLIAGE FLOUR
Cassava Roots flour
The quality of roots submitted to the
dehydration process to obtain cassava flour
has a natural, direct influence in the final
quality of the dehydrated product. Roots
with contaminated impurities of fibre type
(stems, leaves, waste material) or ash type
(sand, soil) affect the nutritional quality,
reducing principally the energy content.
23
Cuadernos Avícolas No. 14
Roots not processed at the proper time or
exposed to deficient, defective or very
extended processes, also result affected in
their final composition, specially from the
sanitary point of view; because they suffer
contamination by micro-organisms
(bacteria and fungi) that affect the animal’s
organism.
It does not exist currently an official
method to grade the quality of cassava
flour for the animal feed industry because
of the multiple possibilities of variation
during the cultivation, harvesting and
processing operations.
Table 7 shows a scheme to measure the
quality of the roots flour, based on the
proposal of Muller et al., 1972, and
complemented by the authors of this paper.
This initiative refers principally to the
parameters of primary importance for
determining the energetic value (main
contribution of the root), and giving a
secondary value to the nutritional elements
of less importance on the root (protein,
amino acids).
Based on the above classification, it is
possible to recommend the use of cassava
Table 7. Qualification of the
nutritional quality of cassava flour.
Critical ingredients content
Grade
Raw fiber
%
1
< 2.8
2
< 3.6
3
< 4.5
4
< 5.2
From: Buitrago, 1990.
24
Ashes
%
Metabolic energy
Mcal/kg
< 2.0
< 2.5
< 3.2
< 4.0
> 3.30
> 3.15
> 2.92
> 2.60
Table 8. Nutritional composition of
cassava flour obtained from peeled
and non-peeled roots.
Nutrients
Dry material
Carbohydrates
Protein
Ether extract
Ash
Fiber
Metabolizable energy
Neutral detergent fiber
Acid detergent fiber
Hemicelulose
Roots with
peel
%
Roots without
peel
%
100.0
83.8
2.90
1.04
3.00
5.10
3.20
5.80
4.70
1.10
100.0
92.4
1.40
0.85
2.20
2.80
3.50
3.20
1.90
1.40
From: Buitrago, 1990.
flour, according to more precise nutritional
criteria, well adapted to the different
animal production stages. In the poultry
sector, a first approximation could take
into account the following general criteria
for the use of cassava flour:
First grade: for broiler starters, poultry and
laying birds.
First and second grade: for layers and
reproducers.
First, second and third grade: for laying
hens, reproducers and layers.
In general, it is important to consider that
cassava roots are processed in its integral
form, that is, including the peel. Normally,
the peel represents between 15 and 20% of
the total root’s weight, and the pulp or
central cylinder represents 80 to 85%. The
greater proportion of protein, fat, fibre and
minerals (ash) is located in the peel, while
the carbohydrates (starches) are located in
the pulp. Cassava varieties that produce
Cassava in Poultry Nutrition
small and tiny roots have, in consequence,
a greater proportion of peel, which results
in a cassava flour with more fibre, protein
and ashes and less energy.
Table 9. Nutritional composition of
cassava foliage flour with different
proportions of leaves, petioles and
secondary stem.
Table 8 illustrates the existing nutritional
differences between cassava flour obtained
from non-peeled roots and cassava flour
obtained from peeled roots.
Nutrients
%
Leaves*
Leaves and
Leaf-stalks
Protein
Ash
Fat
Fiber
Calcium
Phosphorus
Potassium
22.7
10.9
6.3
11.0
1.68
0.29
0.69
21.6
9.8
6.3
11.6
1.70
0.24
0.60
Cassava foliage flour
Although there are no precise
specifications about the flour quality that
must be produced commercially, it is
necessary to recognize some important
quality parameters that must be considered
to qualify this flour as an adequate product
for animal feeding.
The aerial part of the cassava plant
considered useful for animal feeding has,
principally, leaves, petiole, primary and
secondary stems. The proportion of
participation of these elements to obtain
the flour, constitutes the first factor
determining the quality of the final
product’s quality: if the proportion of
leaves is greater related to the other
components of the aerial part, then the
nutritional quality of the foliage will be
better.
In order to document these informations,
CLAYUCA ordered laboratory tests at the
Hoofd Veevoeding company from Holland
to evaluate the foliage flour with different
proportions of leaves, petioles and stems,
taken commercial cultivations in the Valle
del Cauca region in Colombia. The results
presented in Table 9 illustrate the
Leaves,
leaf-stalks
and
stems*
20.2
8.5
5.3
15.2
1.68
0.28
1.09
* Products with 8 to 10% humidity
From: Van Poppel, 2001. Analyseuitslagen KB
grondstoffen. Hoofd Veevoeding en Kwaliteit,
Holanda.
differences in the nutritional quality of the
samples containing:
" only leaves
" leaves + petiole
" leaves + petiole + secondary stems
at the normal proportion during the
harvesting of the superior third of the
plant.
In the results presented in Table 9, it is
important to observe that the main change
is associated to a greater level of fibre,
when the secondary stems participate in the
sample. Other nutritional parameters do
not vary much, which indicates that the
product obtained – when the superior third
of the plant is harvested –, can be
considered an ingredient similar to the
25
Cuadernos Avícolas No. 14
alfalfa flour and of great potential
application in the nutrition of layers and
broilers, as a source of protein and natural
pigments.
It is also important to remember that the
variety of the plant, the age, the
fertilization practices, the environment and
the planting distance affect the quality of
the flour.
One of the main factors affecting the
quality and quantity of cassava foliage
nutrients is the age of the material at the
time of the cutting. When early cuts are
made – for example, 2 or 3 months old – in
cultivations oriented towards intensive
production of foliage, it is possible to
obtain the maximum yield in terms of
quality and quantity of nutrients. When the
cutting of the foliage is made
simultaneously with the harvesting of the
roots or when the age of the plant is
superior to 8 or 9 months, the proportion
of leaves related to the stems is lesser,
which has an important effect over the
nutritional content of the product as it was
explained before.
Table 10. Essential amino acid
contents in cassava foliage flour.
As a
percentage
of the dry
product
Methionine
0.36
Lysine
1.87
Threonine
1.35
Leucine
2.72
Arginine
1.48
Fenilalanine
0.92
Tryptophane
0.24
Valine
0.99
Tirosine
0.89
Isoleucine
1.67
From: Buitrago, 1990.
As a
percentage
of the protein
1.3
6.7
4.8
9.7
5.3
3.3
0.8
3.5
3.2
5.9
Likewise, the fibre variations can fluctuate
from 10%, if the product has many leaves,
to more than 20% in the case of samples
with a high proportion of stems. According
to the fibre and ashes contents, the
concentration of metabolizable energy is
calculated between 1.300 and 1.800
kilocalories per kg, approximately.
The average content of the main amino
acids in cassava foliage flour is illustrated
in Table 10.
The greater nutritional variations in the
foliage flour refer to concentration of
protein fibre and metabolizable energy.
While the fibre level increases with the age
of the plant, the concentration of protein
and energy decreases.
INCLUSION LEVELS OF
CASSAVA FOLIAGE AND
CASSAVA ROOTS FLOUR IN
POULTRY DIETS
The protein content can change from 25%,
in cuttings of tender foliage (2 to 3 months
old), to values inferior to 20% in more
mature foliage and with lower leaves
density.
Before proceeding to incorporate cassava
foliage and cassava roots flour in a
program for poultry feeding, it is necessary
to analyse some external and internal
factors from the production’s environment.
26
Cassava in Poultry Nutrition
The most important external factors refer to
the production phase for poultry, The
processing method (flour, pelleted,
crombellized, extruded, etc.) of the final
balanced feed product and the
complementary ingredients that will be
included in the diet. The internal factors are
principally related to the quality, availability
and price of the cassava products.
It is important to take into account that the
processing system of the final balanced
feed is a fundamental external factor to
decide on the level of cassava roots flour
that can be included in the diet. Cassava
flour is a rather dusty product, very volatile,
that causes management problems when it is
mixed with other floury products of the
diet. This limitation is evident during the
fabrication and when the product is given to
the animal in its floury form.
To counteract this situation, the maximum
level of cassava flour inclusion is generally
around 25 to 30% or otherwise oil or sugar
cane molasses may be added to reduce the
dusty feature of the diet.
In the case of broilers, it is important to
remember that most of the time, the diets
are elaborated in form of pelleted,
crombellized or extruded products. This
modality allows using maximum levels of
cassava flour, eliminating the
inconveniences of the dusty presentation
that characterises the cassava flour
In relation with cassava foliage flour, the
most limiting external factor for the use of
cassava foliage flour is the fibrous
characteristic of the foliage that, as it is the
case with other types of foliage, does not
allows the inclusion of levels higher 6-8%
in the final diet. The high fibre
concentration and the palatability problems
of the forages are directly associated with
the low level accepted in poultry diets.
However, the low levels of inclusion give,
anyway, an important contribution of protein
and natural pigments, both in broilers and
layers.
The quality of the cassava roots or cassava
foliage flour depends on many variables as it
has been expressed, which are responsible
for the final performance obtained in the
animal. In the case of poultry, the most
precise and relevant measure to evaluate the
nutritional quality of the root is the
metabolizable energy content; and to
evaluate foliage, besides energy, it is
important to measure the protein quantity
and quality and the xanthophylls
concentration.
In the feeding programs to be analysed, the
inclusion of acceptable quality products is
assumed, from the nutritional and sanitary
point of view. It is also assumed that the
industrial process used guarantees safe
levels in the concentration of cianogenic
acid (< 100 ppm) in roots or foliage and
good criteria in the use of temperature
parameters during the processing to
maintain the quality of the protein or the
xanthophylls in cassava’s foliage.
The majority of experiences conducted with
broilers and layers, cassava integral root flour
(with peels) has been used, which can be
classified within grades 1 and 2, according to
the grading proposed in Table 7.
27
Cuadernos Avícolas No. 14
Multiple alternatives in feeding programs
for broilers and layers can be designed
from products that meet adequate quality
conditions. Some of these alternatives will
be analysed over the next pages, but they
just constitute a sample of the numerous
possibilities that can be developed in
commercial feeding programs.
COMPLEMENTARITY OF
CASSAVA FLOUR AND
INTEGRAL SOYBEANS IN
FEEDING PROGRAMS FOR
POULTRY
Although cassava flour can be
complemented with a large number of
ingredients that provide the nutrients
needed to obtain balanced food rations for
poultry, integral soybeans (full – fat
soybeans) is presented as a very special
and synergetic resource in the design of
programs with high nutritional quality.
The lack of protein and essential fatty
acids that characterize the cassava flour
can be amply satisfied with the use of
integral soybeans. Indeed, a balanced
mixture of cassava flour and integral
soybeans can totally cover the
requirements of energy, protein and
essential fatty acids for broilers and
layers.
As Table 11 shows, the low concentration
in some essential nutrients observed in
cassava roots flour is compensated
satisfactorily considering the composition
of the integral soybeans.
Table 11. Main nutrients in cassava flour and integral soybeans.
Nutrient
Protein
Metabolizable
energy
Fiber
Ash
Fat
Linoleic acid
Lecithin
Starch
Methionine
Cystine
Lysine
Threonine
Thryptophane
%
Cassava roots
flour
2.8
Integral
soybeans
38.0
Mcal/kg
%
%
%
%
%
%
%
%
%
%
%
3.0 to 3.2
2.6
3.2
1.2
0.4
0.1
68
0.03
0.02
0.05
0.05
0.02
3.6 to 3.8
4.9
5.2
19
8.9
2.0
8.0
0.51
0.60
2.31
1.43
0.52
Unit
From: Buitrago y Luckett, 1999.
28
Cassava in Poultry Nutrition
Table 12. Nutritional composition of a cassava flour (82%) and
integral soybeans (18%) mixture.
Nutrients
Cassava flour (82%) +
integral soybean (18%)
Commercial Corn
9
0.46
0.12
0.24
0.28
0.1
0.51
8.5
0.26
0.18
0.35
0.29
0.07
0.40
3.25
3.5
1.7
3.9
3.6
0.29
0.09
3.34
3.6
2.1
2.8
2.1
0.04
0.08
Protein %
Lysine %
Methionine %
Methionine + cystine %
Threonine %
Thryptophane %
Arginine %
Metabolizable energy
Mcal/kg %
Fat %
Linoleic acid %
Fiber %
Ash %
Calcium %
Av. phosphorus %
From: Buitrago y Luckett, 1999.
The specific nutritional requirements for
broiler and layer diets offer favourable
conditions to be satisfied by different
mixtures of cassava flour and integral
soybeans. Likewise, this complementarity
simplifies the design of feeding programs
under commercial conditions.
A mixture constituted by 82 parts of
cassava flour and 18 parts of integral
soybeans becomes a product with similar
characteristics to those of cereals, as can
be seen in Table 12.
The experiences obtained with this type of
product (mixture of 82% cassava flour and
18% integral soybean) or with these
products used independently, have shown
the possibility of obtaining performances
and results that are with those of diets
elaborated using traditional cereals (corn
and sorghum).
The integral soybeans can be processed
using extrusion or toasting methods.
Evaluations conducted using both products
have shown similar results.
In consideration to the observations
discussed above, the following sections of
this document will present and discuss
various animal feeding programs for
poultry (broilers and layers), based on
different mixtures of cassava roots flour
and processed integral soybean (extruded
or toasted).
29
Cuadernos Avícolas No. 14
BROILER FEEDING
Considering that the balanced feed for
broilers is generally prepared in the form
of a pelletized or crombellized product,
the recommendations for the levels of
cassava roots flour that can be used can be
as high as the total substitution of cereal
grains in diets for starting and finishing
broilers.
The dusty feature of diets with high content
of cassava roots flour is totally overcome
during the pelletization process, without
the need to use special additives. This type
of diet allows the inclusion of the
maximum levels of cassava roots flour
(45-50%) and cassava foliage flour
(5-6%). When the starting point is the
mixture of cassava roots and cassava
foliage flour, integral soybeans and
Table 13. Example of a complete ration for broilers
based on cassava products and integral soybeans.
Ingredients %
Cassava roots flour
Cassava foliage flour
Integral soybean (toasted)
Soybean meal
Palm oil
DI - methionine
Dicalcium phosphate
Calcium carbonate
Salt
Vitamins and minerals
Anticoccidial and additives
From: Gil et al., 2000.
Roots
45.7
3.0
18.7
2.9
0.29
1.52
0.38
0.3
0.1
+
Starter
Roots and foliage
40.4
6.0
30.0
16.4
4.5
0.29
1.52
0.38
0.3
0.1
+
Roots
49.8
41.6
5.2
0.23
1.52
0.38
0.3
0.1
+
Finish
Roots and foliage
46.0
6.0
45.1
0.3
0.23
1.5
0.32
0.3
0.1
+
Table 14. Nutritional composition of diets for broilers based
on cassava products and integral soybeans.
Main nutrients
Metabolizable energy, mcal/kg
Protein, %
Methionine, %
Methionine + lysine, %
Lysine, %
Linoleic acid, %
Calcium, %
Av. Phosphorus, %
From: Gil et al., 2000.
30
Roots
3.22
22.00
0.59
0.90
1.26
3.41
0.91
0.42
Starter
Roots and foliage
3.22
22.00
0.59
0.90
1.26
3.56
0.91
0.42
Roots
3.18
20.00
0.49
0.78
1.12
3.60
0.96
0.40
Finish
Roots and foliage
3.18
20.00
0.49
0.78
1.12
3.85
0.90
0.40
Cassava in Poultry Nutrition
Table 15. Diets based on cassava roots flour and cassava
leaves flour for broilers in the starting phase.
Ingredients
%
Control
Corn
Cassava root flour
Foliage flour
Integral soybeans
Palm oil
Soybean meal
DI-methionine
L-Lysine
Bone meal
Calcium Carbonate
Salt
Vitamins and minerals
59.37
E. met, mcal/kg
Protein, %
Methionine, %
Met. + Cystine, %
Lysine, %
Linoleic acid, %
Calcium, %
Av. phosphorus , %
3.20
22.00
0.59
0.90
1.26
2.62
0.91
0.42
12.80
3.00
21.00
0.16
0.07
1.70
1.50
0.30
0.10
Solar
Cassava root's flour
Equipment A
Equipment B
Root flour
and foliage flour
45.75
45.75
45.75
30.00
2.90
18.70
0.29
30.00
2.90
18.70
0.29
30.00
2.90
18.70
0.29
40.45
6.00
30.00
4.50
16.40
0.29
1.90
1.90
1.90
1.90
0.30
0.10
0.30
0.10
3.20
22.00
0.59
0.90
1.26
3.42
0.91
0.42
3.20
22.00
0.59
0.90
1.26
3.56
0.91
0.42
0.30
0.30
0.10
0.10
Nutritional Composition
3.20
3.20
22.00
22.00
0.59
0.59
0.90
0.90
1.26
1.26
3.42
3.42
0.91
0.91
0.42
0.42
Table 16. Diets based on cassava roots flour and cassava
leaves flour for broilers in the finishing phase.
Ingredients
%
C assava root's flour
C ontrol
Corn
Cassava root flour
Foliage flour
Integral soybeans
Soybean m eal
D I-m ethionine
L-Lysine
Bone m eal
Calcium Carbonate
Salt
V itam ins and m inerals
66.85
E. m et, m cal/kg
Protein, %
M ethionine, %
M et. + Cystine, %
Lysine, %
Linoleic acid, %
Calcium , %
A v. phosphorus , %
3.20
20.00
0.49
0.78
1.12
2.20
0.90
0.40
6.10
20.70
0.13
0.19
1.60
1.10
0.30
0.10
R oot flour
and foliage
flour
Solar
Equipm ent A
Equipm ent B
49.80
49.80
46.11
41.60
5.20
0.23
41.60
5.20
0.23
41.60
5.20
0.23
1.90
1.90
1.90
1.80
0.30
0.10
0.30
0.10
3.20
20.00
0.49
0.78
1.12
3.60
0.90
0.40
3.20
20.00
0.49
0.78
1.12
3.85
0.90
0.40
0.30
0.30
0.10
0.10
N utritional Com position
3.20
3.20
20.00
20.00
0.49
0.49
0.78
0.78
1.12
1.12
3.60
3.60
0.90
0.90
0.40
0.40
46.10
6.00
45.10
0.23
31
Cuadernos Avícolas No. 14
soybean meal, it is possible to formulate a
perfectly balanced diet for broilers, in
which these ingredients can represent up to
95% of the total feed, as illustrated in
Table 13.
The nutritional composition of the
mixtures already mentioned can be seen in
Table 14.
Results of feeding programs for
broilers with maximum levels of
cassava flour
CLAYUCA has conducted recently some
experimental work (Gil et al., 2001), with
the support of Fenavi and the Minister of
Agriculture (MADR), to evaluate diets
similar to those presented in Table 13. The
diets were prepared totally based on
cassava flour (from roots and foliage) and
integral soybeans and were compared with
a commercial ration based on corn and
integral soybean. In the case of rations
with cassava roots flour, it was possible to
compare the effect of cassava flour
dehydrated using solar energy and flour
dehydrated using equipments available
commercially. In Tables 15 and 16 the
detailed compositions of the five diets
used for broilers (Ross 308) are included.
Effects in weight gain and feed
conversion:
Table 17 illustrates the performance of the
broilers until 42 days when the trial was
finished. Every group that consumed cassava
flour and integral soybeans had a weight gain
and feed conversion similar or superior to
the control group with corn and integral
soybeans. This effect was observed at the
starting and at the finishing stage. The
consumption of the balanced feed was not
affected in the treatments that included high
levels of cassava flour. The mortality rates
were the same in all the treatments and the
diet type did not influence them.
Effect of the cassava flour
dehydration method:
In the treatments that included cassava roots
flour, the effect of the natural processing
method, by means of the exposure to sun of
cassava chips, and the industrial processing
with artificial heating (steam and propane
gas) were compared, using two commercial
equipments currently available (Protón and
Agroindustrial Processes). The performance
of the chicken was superior when cassava
was processed in any of the two equipments
mentioned, as can be seen
Table 17. Performance of broilers up to 42 days.
Parameter
%
Initial weight, g
Final weight, g
Consumption, kg
Efficiency of feed
convertion
32
Control
39.80
2.14
4.73
Solar
39.50
2.28
4.88
2.21
2.14
Cassava root's flour
Equipment A
Equipment B
39.40
39.50
2.24
2.39
4.65
4.68
2.08
1.96
Root flour
and foliage flour
39.70
2.11
4.72
2.24
Cassava in Poultry Nutrition
in Table 17. Important differences were not
observed when comparing the effect of the
two equipments used. Both were effective
on the process of dehydration and
maintained the final quality of the processed
product. The industrial process guarantees
high temperatures that facilitate the
gelatinisation of starches and allow a better
sanitary control of the final product. These
two factors have probably an important
influence on the superior performance of
the animals fed with high cassava roots flour
levels, in contrast with the natural sun drying
process.
Effect on the humidity of the litter
Although the diets with high percentage of
cassava flour and integral soybeans contain
high potassium levels in its final
composition, it was not observed an adverse
effect related to chicken manure and humid
litters. Analysis was made of the humidity
of the manure in all the experimental
groups, at weekly intervals, and no
significant differences were obtained.
Additionally, the measure of the humidity of
the litter did not indicated differences
between groups.
group with a diet based on cassava roots flour
and cassava foliage flour showed
pigmentation similar to that of the control
group fed with diets based on yellow corn.
The visual appreciation on a scale from 1
(more pale) to 5 (more pigmented), gave the
control group and the group fed with cassava
roots and cassava foliage flour a qualification
of 4, while all the other groups fed with
cassava roots flour without cassava foliage
flour obtained a grade of 2 on the scale.
Results of the feeding programs in
broilers with medium and low levels
of inclusion of cassava flour
Effect on the pigmentation
Even though the results obtained replacing
totally the cereal grains by cassava flour in
pelettised diets have demonstrated that this
could become a viable practice in
commercial feeding programs for broilers, it
is possible that in many occasions, it is more
convenient to use a partial substitution of the
cereal grains. This last modality is even more
important when the diets are prepared in form
of flour, considering the floury or dusty
characteristic of the diets with percentages of
inclusion of cassava roots flour higher than
20 to 30%.
An important observation throughout the
experiment and by checking at the chicken
carcasses after sacrifice, is related with the
degree of pigmentation of the skin, legs,
mouth and internal fat.. The groups with
diets based on cassava roots flour were
characterized by a poor pigmentation all
throughout the experiment. However, the
Tables 18 and 19 illustrate the composition
of the diets with intermediate levels of
cassava flour, in which the objective was the
substitution of about 50% of the sorghum or
corn used in diets for the starting and finalization phases. Some experiences have
already been conducted with this criterion
with an inclusion of around 20 to 30% of
cassava roots flour on the diet.
33
Cuadernos Avícolas No. 14
Table 18. Diets for broilers with intermediate levels of cassava flour.
Ingredients %
Sorghum
Cassava roots flour
Integral soybeans (toasted)
Soybean meal
Fish meal(65%)
Palm oil
Dicalcium phosphate
Calcium carbonate
DI-methionine
Salt
Choline chloride (50%)
Vitamins and minerals
Anticoccidial
Fungicide
Metabolizable energy, mcal/kg
Protein, %
Methionine, %
Methionine + cystine %
Lysine %
Thryptophane, %
Threonine, %
Linoleic acid, %
Calcium, %
Av. phosphorus, %
Starter
33.65
20.00
32.00
8.20
3.50
0.90
0.80
0.27
0.25
0.12
0.10
0.10
0.10
Nutritional facts
3.15
21.00
0.58
0.88
1.23
0.28
0.60
3.08
0.90
0.43
The results obtained in broilers from
different genetic lines are illustrated in
Tables 20 and 21. In general, it can be
concluded that those that consumed diets
with a substitution of 50% of cereals for
cassava roots flour had the same (or
better) performance than those that
consumed the conventional diets based on
sorghum and corn. In terms of the weight
increase, the efficiency of feed conversion
and carcass yield, did not present
significant differences when compared
with the existing treatments, in both place,
Avités (Cereté, Córdoba), and El Recreo
(Buga, Valle). Adverse effects were not
observed in terms of mortality or
34
Finishing
33.61
25.00
34.00
2.80
4.00
0.10
0.70
0.90
0.22
0.25
0.10
0.10
0.10
0.10
3.20
19.00
0.51
0.77
1.10
0.25
0.59
3.10
0.91
0.40
Source:
Granjas Avités –
Nutrilisto.
Cereté, Córdoba.
Pelleted diets.
morbidity, as a result of the inclusion of
cassava roots flour. Differences in
humidity of the litter used in the different
installations were not appreciable either.
LAYERS FEEDING
Feeding programs for layers generally
involve the use of diets in flour form,
which becomes an important limitation for
the inclusion of high levels of cassava
roots flour. However, when low and
intermediate levels of cassava roots flour
are used, this situation is no longer a
problem for the management of the diets.
Cassava in Poultry Nutrition
Table 19. Diets for broilers with intermediate levels of cassava flour*.
Ingredients %
Starter
Corn
25.34
Cassava (82%) + soybean (18%)*
30.50
Integral soybean (toasted)
25.90
Soybean meal
12.10
Chicken viscera meal
3.00
Dicalcium phosphate
1.30
Calcium carbonate
1.00
DI-methionine
0.23
Salt
0.35
Vitamins and minerals
0.12
Anticoccidial
0.05
Fungicide
0.10
Nutritional composition
E. met, mcal/kg
3.10
Protein, %
22.00
Methionine, %
0.56
Met. + Cystine, %
0.90
Lysine, %
1.24
Thryptophane, %
0.28
Threonine
0.80
Linoleic acid, %
3.25
Calcium, %
0.90
Av. phosphorus, %
0.42
Finishing
30.79
30.50
28.30
4.80
3.00
1.00
0.90
0.10
0.30
0.10
0.10
0.10
3.20
17.00
0.40
0.72
1.10
0.25
0.75
3.48
0.82
0.39
* 82% cassava roots
flour + 18% integral soybeans.
Granjas El Recreo – Carioca.
Buga, Valle
Pelleted diets.
Table 20. Results on the performance of broilers with
intermediate levels of cassava roots flour in the diet.
Parameters
Starting number
Finishing number
Number of days
Mortality, %
Final weight, g
Feed consumption, g
Feed conversion efficiency
European efficiency factor
Control 1
Control 2
36.000
33.531
42
6.0
1.951
3.324
1.70
255
48.441
46.199
42
4.6
1.934
3.559
1.84
239
Cassava flour +
integral soybean
24.000
22.392
42
6.7
1.915
3.152
1.69
259
Granjas Avités – Nutrilisto. Cereté, Córdoba. 40 m.a.s.l. 34-360 C. Tester 1: Sheds with greater environmental control
using ventilators. Tester 2: Sheds with lesser environmental control (like the experimental lot) Pelleted diets.
From: Buitrago and Luckett, 1999.
35
Cuadernos Avícolas No. 14
Table 21. Results on the performance of broilers with
intermediate levels of cassava flour on the diet.
Parameters
Control
Starting number
Finishing number
Number of days
Mortality, %
Final weight, g
Feed consumption, g
Conversion efficiency
European efficiency factor
7.680
7.415
42
3.2
1.976
3.754
1.90
239
Granja El Recreo - Carioca.
Buga, Valle.
1010 m.a.s.l. 25-270 C.
Pelleted diets.
From: Buitrago and Luckett, 1999.
Unless the possibility of using pelletised
or crombellized diets is considered, it is
difficult to incorporate levels higher than
25% of cassava roots flour in diets for
layers. The dusty feature and the high
starch content difficult the management of
the balanced feed with high contents of
cassava roots flour.
In relation with cassava foliage flour, it is
also recommended that its use in diets
should not exceed levels of 5 to 6% to
minimize effects on the palatability.
Likewise, the energy concentration on the
diet makes it difficult to include higher
levels.
When high quality foliage flour is used in
the diet in levels of 5 to 6%, a good
pigmentation is obtained in the egg’s yolk,
due to the presence of natural xanthophylls.
36
Cassava flour
+ integral
soybeans
7.673
7.108
42
5.7
1.942
3.781
1.94
218
RESULTS OF FIELD
EXPERIENCES
The main field experiences have been
conducted in poultry farms located in the
Valle del Cauca and the Atlantic Coast
regions of Colombia. The evaluations have
been developed at different stages of
production, using diets, raw materials and
nutritional parameter from each place. The
first experiences (La Esperanza and Monte
Grande farms) were made with double
purpose cassava varieties from the Atlantic
Coast. In the most recent evaluations
(Santa Anita and Avicauca farms) industrial
cassava varieties from the north part of
Cauca (Agroveléz) were used. The flours
from different varieties were mixed to give
a homogeneous product as raw material for
the elaboration of the final product. In
every experimental work, the diets were
prepared in the form of flour, and the level
of replacement of the corn was 50%. The
composition of the diets evaluated in the
different demonstrative trials is illustrated
in Tables 22, 23, 24 and 25.
Cassava in Poultry Nutrition
Table 22. Diets for layers with 10% inclusion of cassava roots flour.
Ingredients
Control
Corn
57.80
Cassava flour
Soybeans meal
16.20
Toasted soybeans
5.30
Fish meal (65%)
5.00
Wheat bran
3.50
Calcium carbonate
9.71
Calcium phosphate
0.95
Salt
0.30
Liquid methionine (88%)
0.18
Vitamins and minerals
0.10
Additives and pigments
0.50
Nutritional Composition
E. metabolizable, mcal/kg
2.75
Protein, %
17.50
Lysine, %
0.91
Methionine, %
0.44
Methionine + Cystine, %
0.75
Calcium, %
3.90
Av. phosphorus, %
0.45
Linoleic acid, %
1.36
Cassava flour
10%
45.30
10.00
15.00
9.10
5.00
3.50
9.64
0.91
0.30
0.20
0.10
0.50
2.75
17.50
0.91
0.44
0.75
3.90
0.45
1.39
Avícola La Esperanza. Buga, Valle. 1000 m.o.s.l. 260 C- 75% R.H.
From: Gutiérrez and Martínez, 1998. U. Nacional.
The summary of the results obtained with
the animal feeding programs cited before
is analysed in Tables 26, 27, 28, 29
and 30.
No important differences were observed
in the production parameters (eggs laying
percentage and conversion efficiency).
Every production parameter analysed was
compared with the normal standards of
production for each line and poultry age
and the results obtained were always within
the normal ranges. Also, in
otherparameters such us percentage of
mortality or morbidity in lots were poultry
consumed diets with intermediate levels of
cassava flour, there were not observed any
significant differences. The quality and
humidity of the litter did not suffer
important alterations.
37
Cuadernos Avícolas No. 14
Ingredients
Control
Corn
41.10
Cassava flour
Soybean meal
8.10
Extruded soybean
20.00
Rice polishings
10.00
Wheat bran
9.10
Calcium carbonate
9.60
Calcinated bone meal
1.30
Salt
0.35
DI-methionine
0.18
Vitamins and minerals
0.20
Additives and pigments
0.10
Nutritional Composition
Metabolizable energy,
2.75
mcal/kg
Protein, %
17.00
Lysine, %
0.85
Methionine, %
0.45
Methionine + Cystine, %
0.70
Calcium, %
3.90
Av. phosphorus, %
0.42
Linoleic acid, %
1.74
Cassava
flour
15%
34.10
15.00
11.60
20.00
7.60
9.30
1.50
0.35
0.19
0.20
0.10
2.75
17.00
0.85
0.45
0.70
3.90
0.42
1.37
Granja Avícola Santa Anita. Pradera,
Valle. 1010 m.o.s.l. 260 C. 78% R.H.
From: ASA, 2000.
Granja Avícola Montegrande.
Tuluá, Valle. 1025 m.o.s.l. 250 C.
78% R.H.
From: Gutiérrez and Martínez,
1998. U. Nacional.
38
Table 23. Diets for layers with 15%
inclusion of cassava roots flour.
Table 24. Diets for layers with 20%
inclusion of cassava roots flour.
Ingredients
Control
Sorghum
30.60
Corn
20.00
Cassava flour
Soybeans meal
12.30
Toasted soybeans
15.00
Wheat bran
10.30
Calcium carbonate
9.20
Calcium phosphate
1.40
Salt
0.35
Liquid methionine (88%)
0.23
Vitamins and minerals
0.10
Additives and pigments
0.50
Nutritional Composition
Metabolizable energy,
mcal/kg
2.70
Protein, %
17.00
Lysine, %
0.85
Methionine, %
0.45
Methionine + Cystine, %
0.70
Calcium, %
3.90
Av. phosphorus, %
0.42
Linoleic acid, %
1.74
Cassava
flour
20%
36.20
20.00
16.50
15.00
0.20
9.30
1.60
0.35
0.23
0.10
0.50
2.70
17.00
0.85
0.45
0.70
3.90
0.42
Cassava in Poultry Nutrition
Table 25. Diets for white and red layers with 10 and 20%
inclusion of cassava roots flour.
Cassava
flour
10%
Corn
41.10
34.10
Cassava flour
10.00
Soybeans meal
8.10
10.40
Extruded soybeans
20.00
20.00
Rice polishings
10.00
10.00
Wheat bran
9.10
4.30
Calcium carbonate
9.60
9.50
Calcinated bone flour
1.30
1.40
Salt
0.35
0.35
DI-methionine
0.18
0.19
Vitamins and minerals
0.20
0.20
Additives and pigments
0.10
0.10
Nutritional Composition
Metabolizable energy,
mcal/kg
2.70
2.70
Protein, %
17.00
17.00
Lysine, %
0.85
0.85
Methionine, %
0.45
0.45
Methionine + Cystine, %
0.70
0.70
Calcium, %
3.90
3.90
Av. phosphorus, %
0.42
0.42
Linoleic acid, %
1.74
1.49
Ingredients
Control
Cassava
flour
20%
23.00
20.00
11.80
20.00
10.00
3.60
9.40
1.40
0.35
0.21
0.20
0.10
2.70
17.00
0.85
0.45
0.70
3.90
0.42
1.37
Avicauca. Jamundí, Valle.
1005 m.o.s.l. 250 C. 76% R.H.
From: ASA, 2000.
Table 26. Layers performance with a 10 % inclusion of
cassava flour in the diet – from week 48 to 55.
Yielding
Consumption/hen/day, g
Egg laying, %
Conversion per dozen of eggs
Control
Cassava flour
10%
102.6
89.2
1.4
103.2
89.5
1.4
Avícola La Esperanza. Buga, Valle. 1000 m.o.s.l. 260C. 75% R.H.
From: Gutiérrez and Martínez, 1998. U. Nacional.
39
Cuadernos Avícolas No. 14
Table 27. Lohmann Brown layers performance with 15%
inclusion of cassava flour in the diet – week 55 to 61.
Performance
Number of layers
Consumption/hen/day, g
Egg laying, %
Conversion per dozen of eggs
Control
Cassava flour 15%
15.00
114.00
78.30
1.37
5.00
115.00
79.00
1.37
Granja Avícola Santa Anita. Pradera, Valle. 1010 m.o.s.l. 260 C. 78% R.H.
From: ASA, 2000.
Table 28. Layers performance with 20% inclusion
of cassava flour in the diet – weeks 39 to 46.
Performance
Consumption/hen/day, g
Egg laying, %
Conversion per dozen of eggs
Control
Cassava flour
20%
111.6
92.4
1.5
111.1
91.0
1.46
Granja Avícola Montegrande. Tuluá, Valle. 1025 m.o.s.l. 250 C. 78% R.H.
From: Gutiérrez and Martínez, 1998. U. Nacional.
Table 29. White layers (Hy-Line) performance with 10%
inclusion of cassava flour on the diet – week 78 to 88.
Yielding
Number of layers
Consumption/hen/day, g
Egg laying, %
Conversion per dozen of eggs
Control
Cassava flour
15%
10.464
107.50
64.10
2.01
8.976
105.50
63.00
2.01
Avicauca. Jamundí, Valle. 1005 m.o.s.l. 250 C. 76% R.H.
From: ASA, 1999.
40
Cassava in Poultry Nutrition
Table 30. Red layers (Lohmann Brown) performance with 10 and
20% inclusion of cassava flour in the diet – week 78 to 88.
Yielding
Control
Cassava flour
10%
Cassava flour
20%
3.840
115.10
69.30
2.00
10.956
115.80
65.70
2.12
5.160
114.80
65.10
2.11
Number of layers
Consumption/hen/day, g
Egg laying, %
Conversion per dozen of eggs
Avicauca. Jamundí, Valle. 1005 m.o.s.l. 250 C. 76% R.H.
From: ASA, 1999.
GENERAL CONCLUSIONS
Cassava plants offer two valuable resources
for the animal feed industry: roots and
foliage. While roots constitute an important
source of starch and energy, foliage mainly
contributes with protein and natural
pigments.
In the majority of tropical regions the
cassava crop appears as a profitable
alternative to partially or totally replace the
cereal grains traditionally used for poultry
feeding. The concentration of calories
obtained per unit of cultivated area amply
overcomes the concentration obtained from
cereals.
The cassava crop adapts easily to a great
range of agricultural areas with altitudes
under 1.800 m above sea level, where yields
of cassava roots and foliage are usually
higher than those obtained with other
commercial crops.
The integration of the cassava crop with
poultry production programs demands
special efficiency and industrialization
schemes to be able to guarantee the cassava
volumes needed, at competitive prices, to
replace the traditional inputs.
The use of high yielding cassava varieties,
the mechanization of planting and
harvesting, the industrial processes of
post-harvest dehydration and the
implementation of transportation and
continuous processing systems, are some
of the fundamental requirements for the
establishment of an effective integration
with the poultry sector.
Recently, some industrial equipment has
been developed at the local market for
planting and harvesting cassava roots and
foliage as well as for the roots and foliage.
These advances constitute significant
progress in industrial processes of high
efficiency, with the subsequent reduction in
production costs.
The traditional dehydration method of the
roots in cement floors is well adapted for
small-scale operations. For an industrial
operation, in large scale, it is important to
introduce artificial systems of dehydration
41
Cuadernos Avícolas No. 14
that guarantee a better nutritional and
sanitary quality of the final product.
Due to the protein deficiency in the
cassava roots flour, the price of this
product must be inferior to the corn price,
in 25 to 30%, approximately.
Figure 13. In relation with cassava
foliage flour, it is also recommended
that its use in diets should not
exceed levels of 5 to 6% to minimize
effects on the palatability.
SPECIFIC CONCLUSIONS
In broiler and layers feeding, cassava roots
and cassava foliage flour are excellent
sources of energy, protein and natural
pigments.
Although the level of inclusion of cassava
roots in the diets does not have an
important limitation, cassava foliage flour
must not be included in levels higher than
5 or 6%, in diets for broiler or layers. The
fibre content and the low level of energy
limit its use in higher percentages.
The cassava roots flour has important
limitations in the protein and fatty acid
content. This is a reason why the balance
of the final diet requires an effective
complementation of these two nutrients. In
numerous experimental works it has been
demonstrated that the integral soybeans is
an excellent alternative in the majority of
the cases.
As long as the broiler diet is pelletised, the
cassava flour level can totally replace the
42
cereal grains, without affecting the
performance. For diets in the form of
flour, it is not recommended to include
levels higher than 25% of cassava flour,
due to the dusty characteristic of the final
diet, which causes difficulties in
consumption.
According to the studies realized, cassava
roots flour can totally replace cereals, as
long as the diets are pelletized. In the case
of diets presented in the form of flour, it is
recommended to replace cereals up to
50% for cassava roots flour, which is
equivalent to an approximate level of 25%
cassava flour in the total diet.
Cassava in Poultry Nutrition
REFERENCES
Best, R. y G. Gómez. 1982.
Procesamiento de las raíces de yuca para
alimentación animal. En: Domínguez,
C.E. (ed). Yuca: Investigación, producción
y utilización. International Center for
Tropical Agriculture, CIAT. Cali, Colombia
660 pp
Buitrago, J. A. 1990. La yuca en
alimentación animal. International Center
for Tropical Agriculture, CIAT. Cali,
Colombia. ISBN 958-9183-10-7. 446 p.
Buitrago, J. A. y L. Luckett. 1999.
Potencial de la yuca industrial para
producción de alimentos animales.
Publicación ASA (Asociación Americana
de Soya). Reporte de trabajos
demostrativos. Cali, Colombia. 27 p.
CIAT. International Center for Tropical
Agriculture. Cali, Colombia. Annual
Reports. Cassava Program
CLAYUCA. Latin American and Caribbean
Consortium to Support Cassava Research
and Development. Technical Reports
2000-2001.
Gómez, G. Y J. A. Buitrago. 1982. Effect of
processing on nutrient content of feeds:
root crops. En: Reichcigl, M. (ed.).
Handbook of nutritive value of processed
food, vol. II. CRC Presss. Boca Raton,
USA. p. 221-239.
Gutiérrez, y Martínez. 1998. Efecto de
utilizar harina de yuca y soya integral en
dietas para aves ponedoras. Zootecnia
Faculty. Thesis of degree. U. Nacional.
Palmira, Colombia.
Mueller, Z., K.C. Chou, K.C. Nash y T.K.
Tang 1972. Study of nutritive value of
tapioca in economic rations for
growing-finishing pigs in the tropics.
UNDP Project Sin 67/505. Pig and Poultry
Research and Training Institute. Singapore.
35 p.
Rosero, D.F. 2001. Evaluation, production
and quality of foliage in production
systems of cassava (Manihot esculenta
Crantz), with manual periodical cuttings.
(CLAYUCA) Thesis (Agronomist).
U. Nacional. Palmira, Colombia. 48 p.
Gil, J. L., G. Escobar y J. A. Buitrago.
2001. Evaluación técnica y económica de
cuatro dietas a base de harina de yuca y
una dietacomercial para la alimentación
de pollos de engorde. Technical Report.
CLAYUCA (CIAT). 14 p.
43
Cuadernos Avícolas No. 14
APPENDIX
SOME MANUFACTURERS OF CASSAVA PRODUCTION
AND PROCESSING EQUIPMENTS:
Inversiones ARMARE Ltda..
Calle 42 No. 35-30. A.A. 1015
Phone: (575) 370 90 27 - 379 59 39
Fax: (575) 379 30 34
E- mail: awasembe@celcaribe.net.co
Barranquilla, Colombia
INGENIERÍA MUSKUS
Circular 2 No. 71-28
Phone-fax: (574) 411 42 91
Medellín, Colombia
PLANTICENTER. INDUSTRIA DE
PLANTADEIRAS LTDA.
Avenida Montreal No. 43. Jardim
Panorama.
Phone-fax: (044) 264 14 31
Sarandi, Paraná, Brasil
www.planticenter.com.br
EMPRESA METALÚRGICA
COLOMBIANA, EMC
Carrera 19 No.16-75
PBX (577) 635 23 50 - 635 19 16
A.A. 978
Bucaramanga, Colombia
E-mail:
emcger@multicomputo.multinet.com.co
44
PROCESOS INDUSTRIALES
Calle 6 No. 18-06
Phone: (572) 227 14 20
Buga, Colombia
A.A.10938
Cali, Colombia
E-mail: paila@telesat.net.co
Industrias PROTÓN Ltda.
Carrera 53A No.9-42
Phone: (571) 564 30 66
Bogotá, Colombia
E-mail: proton@colomsat.net.co
STABRA INDUSTRIA COMERCIAL
Rua Campo das Palmas 205 Centro
Holambra.
Phone-fax: (19) 820 11 31
Sao Paulo, Brasil
E-mail: stabra@sigmabbs.c