Soybean forage as a source of protein for livestock in Cuba
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Second FAO Electronic Conference on Tropical Feeds
Livestock Feed Resources within Integrated Farming Systems
SOYBEAN FORAGE AS A SOURCE OF PROTEIN FOR LIVESTOCK IN CUBA
Rena Perez
Dpto. Producciones Agropecuarias No-caneras
Calle 23 y O, Vedado
Ministerio del Azucar
La Habana, Cuba
E-mail: 71055.111@compuserve.com
ABSTRACT
The use of milk-stage soybean forage as a source of protein
for livestock production in Cuba is still in its infancy, and
perhaps, the fact that the only performance data in this
entire report refers to the average weaning weight of seven,
40-day-old piglets, as 8.8 kg, definitely supports this
observation. The sow s diet consisted of sugarcane juice and
soy forage, and the piglets, in addition to nursing, had
access to the same feeds. Presently, in more than 100
sugarcane-sector farms or coops, green soybeans are being used
as a source of protein for livestock. In Cuba, 156 sugar mills
and 1300 cane coops employ nearly half a million workers, and
all have to be fed. Since 1983, the cane-sector, the sector
responsible for cultivating one-third of total arable land on
the island, has endeavoured to produce all its
agricultural-based food needs and has promoted livestock
production. For this, a total of 95 thousand hectares are used
to produce rice, beans, tubercles and fresh vegetables, as
well as some animal feeds. The development of sustainable
agronomic systems has been promoted; mostly, because all
available machinery, fertilizers, insecticides, herbicides and
petroleum have been prioritized for the production of
sugarcane.
The use of milk-stage, soybean forage as a protein source for
livestock rather than imported soybean meal or the whole bean,
presently used mostly to produce yogurt for distribution to
children, is an attempt to accommodate the new,
tropics-oriented, zero-grain, livestock production system
(Preston and Murgueitio, 1992) to the present agronomic and/or
economic reality of the sugarcane-sector state farms and coops
in Cuba.
KEY WORDS: Protein source, soybean forage, soybean hay, green
soya, feed, pig
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INTRODUCTION
Since 1983, the cane-sector, has endeavoured to produce its
basic food needs and has promoted livestock production for its
half-million workers and their families. For this, a total of
95 thousand hectares in 156 sugarmills is used to produce
rice, beans, tubercles and fresh vegetables, as well as some
animal feeds. In 1989, the sugarmills attempted to plant, for
the first time, 5 thousand hectares of soybeans, for seed, in
rotation with cane; it was a failure. Soon after, in 1993, the
sugarmill cane plantations were reorganized into approximately
1300 cane cooperatives and most of the livestock belonging to
the sugarmills, particularly the reproductive herds of pigs,
rabbits and sheep, and the oxen, were given to the co-ops. All
of a sudden, the co-ops found themselves, with animals to
feed, sugarcane and some molasses as sources of energy, but
zero protein feed resources.
Soybeans, until 1940, were used in the United States as
forage, green manure, silage, and hay for horses; in fact, it
was not until 1940, that production of soybeans for beans
surpassed their production for hay. Recently, in Cuba, it was
thought that the same plant, if fed green, while still in the
milk-stage, prior to the presence of the anti-trypsin factor
encountered in the seed, might serve as a source of protein
for pigs. It worked, the idea spread (Perez 1995; 1996, and
presently, in more than 150 cane co-ops and sugarmill farms,
soybean forage is used as the single-most important source of
protein for many kinds of livestock. The system is developing
at a very fast pace because it is sustainable and
"farmer-friendly" and, following initial planting, within 8 or
9 weeks before the forage has had time to become insect or
disease ridden, it is ready to harvest and feed. In addition,
the input is very low: seeds, inoculant, water and care.
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ZERO-GRAIN LIVESTOCK PRODUCTION SYSTEM
When grains are used for livestock, approximately one-half of
the requirement for protein is met by the cereal component;
however, in the case of "zero-grain" production systems in
which the energy and protein components are offered separately
(Table 1), due to the invariable low level of protein in the
basal diet, almost all the requirements for amino acids must
be supplied by the supplement (Preston 1995). In the case of
the cane co-ops and sugarmill farms, they produce different
energy sources, such as: sugarcane, cassava, sweet potato and
bananas, but insufficient protein feed resources.
A further consideration related to the "zero-grain" feeding
system is that, a fast growth rate, per se, one which would
invariably involve feeding a biological optimum supply of
dietary protein, is not necessarily the most profitable. For
example, for pigs from 25-90 kg, "zero-grain" can perhaps best
be summarized in terms of 500 g/day of protein supplement,
approximately 200 g/day protein (Preston 1995).
An attempt to accommodate "the role of monogastric animal
species in the sustainable use of tropical feed resources" (Ly
1993), by providing them locally-produced protein in the form
of soybean forage, is the subject of this preliminary report.
Table 1. Zero-grain pig feeding systems (20-90 kg) *
System** Energy ADG DM Source
DM, % (g) Conversion
Fresh cassava 60-70 650-790 2.80-3.00 Maner et al (1977)
Cooked sweet
potato 73 770 3.50-3.80 Dominguez et al (1991)
Ripe bananas 66-71 560-570 4.50-4.60 Solis et al (1985)
Palm press
fiber 78 500-550 4.50-5.00 Ocampo et al (1990b)
Sugar palm
juice 80 500 - Preston (1995)
Sugar cane
juice 80 650-700 3.50-4.00 Sarria et al (1990)
B molasses 70 500-550 4.00-4.50 Cervantes et al (1984)
C molasses 70 400-450 5.00-5.50 "
* current NRC (1988) performance guidelines for pigs, 50-110
kg, fed 80% maize & 20% soybean meal: 820 g ADG and 3.40 DM
conversion; **under normal farm conditions reduce performance
by 10-15%
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SOYBEAN FORAGE PRODUCTION SYSTEM
The present production system involves planting one, 7-row
plot of soybeans, weekly (Fig.1). Nine weeks later, 63 days,
one row of soybean forage is harvested daily, from Monday to
Sunday (Perez and Ochoa 1996). This means that the
first-harvested row of forage will be 63-days old on Monday,
whereas the following Sunday, the last row of that same plot
will be 70 days old, still presumably in the early milk-stage,
not yet in full expression of the trypsin inhibitor. This
means that the forage can be used directly for pigs, ducks and
rabbits, even chickens. The protease inhibitors, first present
in the formed seed, apparently play an important role as
defense agents against insect attack or micro-organism
infections and would explain the need to boil the whole seed
for 20 minutes prior to feeding monogastrics (EMBRAPA-CNPSo
1994). However, there appears to be very little known about
this factor in the whole soybean plant.
Depending on the time of year, and variety, temperature,
humidity, irrigation and inoculation, the entire system may
vary from between 49-56 to 63-70 days. Excess or older forage
could be sun-dried, perhaps in a manner similar to tobacco,
and used as hay for rabbits or ruminants, or perhaps even
ground and heat-treated (boiled), and used as whole soybean
plant meal. In this regard, the seed or bean is 50% of total
biomass.
PLANTING
The recommended distance between rows for forage is 35 cm, as
opposed to 70 cm, when planted for seed. Each plot will be
approximately 2.5 m wide. By planting 20 seeds per meter at a
depth of 2 cm and with 75% germination, the yield should be
about 15 plants per meter, the current recommendation for one
pig, daily. After completing the harvest of the last row on
Sunday, the same plot is replanted the following week. In this
manner, by replanting the same plot up to 6 times per year, a
significant amount of forage can be produced in small area,
and often adjacent to the enclosed animals.
In Vietnam, where soybeans have been planted in order to take
advantage of 55 growing days between harvesting and planting
the next rice crop, and ensiled, a total of 8.1 t/ha of soy
forage was produced, the equivalent of 360 kg of protein or
the same quantity that would have been obtained from one
hectare of soybeans harvested as seed. Furthermore, the feed
cost per kilogram of gain decreased by 24% in an experimental
group of pigs that obtained 30% of their protein needs from
the ensiled soybean forage. (Chinh et al 1993). In Cuba, under
commercial conditions, and a 75-day growing period,
non-inoculated seeds produced a yield of 24 t/ha of forage
compared to 46 t/ha, or practically double, when the seeds
were inoculated (L=A2pez and Frias 1986).
INOCULATION OF SOYBEANS
The following refers to one plot of 7 rows, each row 50-meters
long. Each 50 meter row should produce sufficient forage,
daily, for about: 20 pigs, 40-50 rabbits and ducks, and part
of the forage needs for 8-10 milking cows. Each plot will
require approximately one kilogram of seeds, because: 1 m =3D 20
seeds; 1 g seeds =3D 5-8 seeds; 1 m =3D 3 g seeds; 50 m =3D 150 g
seeds; and 7 rows =3D 1050 g seeds. To inoculate one kilogram of
seeds:
1. Dissolve one teaspoon (2 g) of sugar in two tablespoons (20
g) of water or use diluted molasses or fresh cane juice.
2. Add one tablespoon (10 g ) of inoculant and combine
thoroughly.
3. Add this mixture to 1 kg of soybeans, mix thoroughly, place
in the shade to dry.
4. Plant seeds as soon as possible, prevent contact with the
sun.
IRRIGATION
Most of the farmers questioned agreed that for best results
all plots require a weekly irrigation. Many methods are
available, but perhaps, one of the simplest systems observed
was to place a 55-gallon drum at the end of each plot, fill
with water, and using a pail, apply one condensed-milk can
full of water, at the base of every plant, every week!
HARVESTING AND CHEMICAL ANALYSIS
Harvesting is done by hand and, if the seeds were inoculated
prior to sowing, the forage should preferably be cut in order
to leave the roots with adhering nodules in the soil. The
following information (Table 2) was obtained using milk-stage
soy forage (INIFAT V-9) grown on non-fertilized,
garden-leached soil in Havana. Even though the crude protein
level of the forage was low, the in vitro ileal digestibility
of nitrogen was 67%, which compares favorably to the average
digestibility of this nutrient in soybean meal, 75%, and to
the average digestibility of nitrogen in most forages,
reportedly, of between 35 and 40 percent.
Table 2. Proximal analysis and essential amino acid
composition of the aerial part of soybean plant*
Proximal components % DM Essential amino acids % DM
Ash 9.97 Arginine 0.46
Calcium 1.38 Cystine 0.17
Phosphorus 0.51 Isoleucine 0.43
Crude fat 4.75 Leucine 0.72
Crude fiber 34.23 Lysine 0.44
Crude protein 12.62 ** Methionine 0.13
Threonine 0.34
Valine 0.57
IIP (1995); * non-inoculated seeds; ** in vitro ileal
digestibility, 67%; The dry matter (DM) was 29.4% and Mj/kg DM
was 16.65.
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SOYBEAN FORAGE FOR LIVESTOCK: GUIDELINES
The use of soy forage for livestock is too recent to publish
guidelines, hopefully, this communication will help remedy
that situation. In fact, the only performance data for this
entire report was the 8.8 kg average weaning weight of seven,
40-day-old piglets, from a sow fed free-choice sugarcane juice
and soy forage in a sugarmill pig farm in central Cuba. The
piglets received no additional feed but had access to the sow,
and naturally, some of the same ration.
PIGS: feed twice-daily soybean forage, approximately one
meter/pig/day, and a free-choice source of energy: sugarcane
juice, diluted molasses, cassava or ripened bananas. Change
diets over a one week period, approximately. In several
provinces, the present idea is to set up small pig fattening
units directly in the banana plantations, adjacent to the
weighing/grading stations, and completely enclose one pig pen
to use it as a banana ripening room. The protein will be
planted alongside: soybean forage.
RABBITS: growers and fatteners can be fed exclusively on
free-choice soy forage, however, for good teeth maintenance in
the reproductive herd, in addition to soy forage, sugarcane
stalks are sometimes offered. One meter of soy forage,
depending on the quality, should be enough for 4 to 5 growing
rabbits, daily. One sugarmill farm reported cutting 0.8 t
daily for a total of 527 rabbits or about 1.5 kg/rabbit/day.
The leftover lower stems were fed to ruminants.
DUCKS: after starting ducks on concentrates or green-feed,
described for chickens, they can be fattened using a
free-choice energy source, cane juice or diluted molasses, and
fresh, whole soybean plants. Once accustomed to soy forage,
they will devour the leaves and most of the stem. The lower
stem can be collected for feeding pigs or ruminants.
LAYING HENS: cassava and soy forage, in a 50:50 ratio, ground
together, is being promoted as "green-feed" for layers.
COWS: soy forage is being promoted for milk cows until the
co-ops and sugarmills produce sufficient forage from protein
trees. Depending on the quantity and quality of the other feed
resources, the present recommended amount is one meter per cow
per day.
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CONCLUSIONS: CONCERNS AND PROBLEMS
The author has been re-called to sugarmills, where the use of
soy forage, formerly promoted, was questioned, because the
younger pigs, 25-50 kg, were not growing as fast as
previously. The answer appeared to be in the age of the
forage, more than 70-80 days, and definitely, with some pods
showing near full-size green beans. There appears to be a
"point of no return", that is, a precise moment at which time
"something" drastic happens, that "something" possibly meaning
the appearance in the bean of the trypsin inhibitor, and its
subsequent effect on effective protein digestion. This,
hopefully, will constitute a key area of research, along with
determining, for the tropics, the preferred forage varieties
for the wet and dry seasons. Interestingly, it has already
been suggested, that the "inhibitor" problem could be avoided
by using a strain of soybeans, the Kunitz strain, that does
not produce the major inhibitor (e-mail/G. Seidel /14/08/96).
In conclusion, certain aspects are already obvious: 1) that,
for the low-income farmer that cannot obtain soybean meal, soy
forage is an interesting and local alternative as a source of
protein, and fatty acids, since it does contain almost 5%
crude fat (Table 2); 2) that, this technology requires only
60-70 days, approximately half the time required to produce
the dry bean; 3) that, because it requires a shorter growing
period, there is less probability for insect and disease
attack; 4) that, soy for forage, if inoculated, and planted 15
days after planting first crop irrigated cane, could improve
cane yields by up to 19% (Perez et al 1992), and finally, 5)
reportedly, for some legume forages, more protein per hectare
is obtained when the forage is harvested in the milk stage
(Oyawoye et al 1990).
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REFERENCES
Cervantes A, Maylin A and Ly J 1984 Utilizacion de distintos
tipos de mieles de cana suplementadas con levadura torula en
crema para cerdos en ceba. Cien Tec Agric Ganado Porcino
7(1):21-36
Chinh B V, Tao N H and Minh D V 1993 Growing and ensiling
soybean forage between rice crops as a protein supplement for
pigs in North Vietnam. Livest Res Rur Devel 5(1):6-11
Dominguez P L, Cervantes A, Mederos C M, Frometa M and
Castellanos M 1991 Uso del tuberculo y la parte aerea del
boniato (Ipomoea batatas (L) Lam) en la alimentacion de los
cerdos en ceba. Res=A3menes IV Congreso ALVEC La Habana Cuba
NA-6
EMBRAPA-CNPSo 1994 Tropical Soybean Improvement and
production. FAO/Rome pp 254
IIP (Instituto Investigaciones Porcina) 1995. Informe interno.
Lopez M and Frias R 1986. Inoculacion de la soya para granos y
forrajes en =A0reas comerciales. Memoria X Reunion ALPA Acapulco
Mexico
Ly J 1993 The Role of Monogastric Animal Species in the
Sustainable Use of Tropical Feed Resources. World Conference
on Animal Production Edmonton Canada p 95-117
Maner, J H, Buitrago J, Portela R and Jimenez I 1977 La yuca
en la alimentacion de cerdos. Bogot=A0, ICA pp 116
NRC 1988 Nutrient Requeriment of Domestic Animales. Nutrient
Requirement of Swine 9th revised ed. National Academy Press
Washington
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legumes as replacements for alfalfa in rabbit diets. J Appl
Rabbit Res 13:32-34
Perez R 1995 CARTA AGROPECUARIA AZUCARERA No. 95.5: El forrage
verde del frijol de soya como fuente proteica. Minaz La Habana
Perez R 1996 Tecnicas agropecuarias para los asentamientos
ecologicos del Minaz Ministerio del Azucar La Habana pp 71
Perez R y Ochoa J 1996 La soya forrajera como fuente proteica.
Livest Res Rur Dev (en imprenta)
Perez L, Crespo R, Creach I and Berra E 1992 Rotacion e
intercalamiento de cultivos en plantaciones caneras. IV
Jornada Cientifica INICA La Habana
Preston T R 1995 Tropical animal feeding: a manual for
research workers. FAO Animal Production and Health Paper FAO
Rome pp 305
Sarria P, Solano A and Preston T R 1990 Utilizacion de jugo de
cana y cachaza panelera en la alimentacion de cerdos. Livest
Res Rur Dev. 2(2):92-100
Solis J, Campabadal C and Ledezma R 1985 Evaluacion de
diferentes formas de suplir el banano en la alimentacion de
cerdos durante la etapa de crecimiento y engorde. Resumenes X
Reunion ALPA. Acapulco Mexico p 40
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LIVESTOCK FEED RESOURCES WITHIN INTEGRATED FARMING SYSTEMS
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