..’ / REPUBLIQUE DU SENEGAL u..” MINISTERE DU...
..’ / REPUBLIQUE DU SENEGAL
u..”
MINISTERE DU DEVELOPPEMENT
RURAL ET DE L’HYDRAULIQUE
INSTITUT SENEGALAIS DE RECHERCHES
A G R I C O L E S ( I . S . R . A . )
DEPARTEMENT DE RECHERCHES SUR LES
PRODUCTIONS ET LA SANTE ANIMALES
LABORATOIRE NATIONAL DE L’ELEVAGE
ET DE RECHERCHES VETERINAIRES
B.P. 2057
D A K A R - HANN
N U T R I T I V E V A L U E O F S O M E TREE
FOR2iGES
S P E C I E S AVAILABLE I N
Si%HELIi%N PASTURES,
BY
FALL-TOURE, s.,
RICHARD, D. ,FRIOT, D., NOLAN, T-l, CONNOLLY,
J.2 and SALL, Ca3 .
ISRA-LNERV BP 2057 DAKAR SENEGAL.
2 TEAGASC ATHENRY CO. Galway. IRELAND.
UNIVERSITY COLLEGE DUBLIN.
Statistics Dept. UCD 4 Dublin
IRELAND
31SRA CRZ DAHRA SENEGAL
R E F . N042/RES.AL.
NOVEMBRE 11992.
2
ABSTRACT :
Quality of some tree forages from West Africa, Acacia albida,
Acacia
raddiana
leaves
and
pods ,
Guiera
senegalensis,
Calotropis procera and Adansonia digitata leaves was studied.
Applied
methodology
involved
chemical
analysis, in
vivo
digestibility, in
sacco
degradation,
intake
and
animal
performances
measurements of
rations
including
different
levels of browses.
Results emphasize the high digestible nutrients content of
Mimosacea pods, C. procera and A. digitata leaves while G.
senegalensis and A. albida old leaves were of poor nutritive
value. Feeding trials involving A. albida pods , C. procera,
A.
digitata and G.
senegalensis
leaves
confirmed chemical
analysis and in vivo digestibilities results. The aptitude to
improve energy and nitrogen level of rations for sheep is high
for A.
albida pods, C. procera and A. digitata leaves. G.
senegalensis at a level superior to 40 pi00
played a negative
role in ration digestion because of low digestibility (30
PlOO), low rumen degradability (deg 48h < 40 ~100) and high
tannin content.
KEY WORDS:
Sahelian pastures, Nutritive value, Tree forages,
Acacia albida, Acacia raddiana,
Adansonia digitata, Guiera
senegalensis, Calotropis procera.
VALEUR NUTRITIVE D'ESPECES FOURRAGERES ARBUSTIVES DISPONIBLES
SUR PATURAGES SABELIENS
Par
FALL-TOURE S., RICHARD D., FRIOT D., NOLAN T.', CONN&LY J.2
and SALL C3.
3
RESUME
La qualité d'arbustes fourragers d'Afrique de l'Ouest, les
feuilles et gousses d'Acacia albida et Acacia raddiana, les
feuilles de Guiera senegalensis, Calotropis procera et celles
d'Adansonia digitata est étudiée.
La
méthodologie
appliquée
porte
sur
les
analyses
chimiques, la digestibilité in vivo, la dégradation in sacco,
et la mesure de l'ingestibilite et des perfomances animales de
rations comportant différents niveaux de ligneux fourragers.
Les résultats mettent en évidence la haute teneur en
nutriments
digestibles
des gousses
de Mimosaceae et des
feuilles de Calotropis procera ainsi que celles d'Adansonia
digitata alors que les feuilles agees d'Acacia albida et
celles de Guiera senegalensis ont eu une valeur nutritive
médiocre.
Ces
résultats ont été confirmés par les essais
alimentaires.
Les gousses d'A.
albida et les feuilles de C.
procera et A. digitata données en complément aux fourrages
pauvres à de jeunes moutons ont permis leur croissance semi-
intensive. G. senegalensis à un niveau superieur à 40 ~100 de
la ration a joué un rôle négatif sur la digestibilité de la
ration probablement a cause d'une faible dégradation intra-
ruminale et d'une teneur élevée en tannins.
PKYrs CLES:
Paturages
sahéliens,
Valeur nutritive, Fourrages
arbustif, Acacia albida, Acacia raddiana, Adansonia diqitata,
Guiera seneqalensis, Calotropis procera.
INTRODUCTION:
Sahelian soils are well reputed for their deficiencies in
organic matter and phosphorus. Pastures are more affected by
drought and soi1 degradation than cultivated lands which are
yearly
improved by
manure
and or
fertilizer.
Thus a
proliferation of plant indicators like Calotropis procera or
Zornia qlochidiata is observed in the Sahel. During ten past
4
years, the situation has been specially enhanced by bush fire
and predators like locust.
The aerial part of pastures, made
of trees and shrubs plays a significant role in ecosystem
maintenance as it has a great capacity of regeneration and
drought resistance.
Most of them are ever green and are an
invaluable
feed
resources
available
a11
over
the
year.
Therefore, browses
are the main ruminants nutrients source
providing nitrogen minerals and vitamins during the dry season
(Le Houerou 1980).
Although the behaviour of ruminants differs according to
seasons and plant species, browses represent up to 30, 70 and
80 pi00 of cattle sheep and goat diet respectively during the
dry season (Guérin, 1987.).
600
species
has
been
identified as
potential
feed
resources for cattle, sheep and goats (Von Maydell, 1983., Le
Houerou
1980).
Available résults gives informations about
their palatability and chemical composition. The high nitrogen
content of tree forages is well known (Riviere, 1978.; Le
Houerou, 1980.; Kearl, 1982.; Koné, 1987.). That nitrogen may
not be available in the digestive tract (Fall, 1991.) and data
about digestibility and influence on animal performances are
scarce. That topic was described as a "top priority subject in
African livestock nutrition todayVt (Le Houerou, 1980.)
We intended to evaluate nutritive value of Acacia albida
and Acacia raddiana leaves and pods,
Guiera
senegalensis,
Calotropis
procera
and
Adansonia
digitata
leaves.
Those
species
are
popular
and
well
represented in
sahelian
ecosystems. A. albida and A. raddiana pods are sold in some
west African markets and CI
procera has been increasingly
available in sahelian pastures as a consequence of drought and
soi1 degradation .
MATWIALS AND MEZHODS:
S!CUDY SITE:
In vivo measurements has been performed in Dahra an ISRA
station located 270 km in the north east of Dakar in the
sahelian zone of Senegal at 15"North,
and 15OWest Longitude.
5
Average rainfall was 340 mm during past twenty years ranging
from 570
to 110 mm.
SAMPLE COLLECTION AND PREPARATION:
Tree forage samples has been collected in Dahra zone,
sundried and stored for in vivo trials.
For each specie a
subsample has been ground to pass lmm sieve for chemical
analysis .
CHEMICAL ANALYSIS:
Chemical analysis was carried out in LNERV-ISRA Station
laboratory of Dakar. They involved dry matter, crude protein,
ash, calcium and phosphorus evaluation (AOAC 1975). NDF, ADF
and lignin were analysed according to Goering and Van Soest,
(1970) and Sodium, potassium, copper and zinc were determined
with atomic absorption spectrosphotometry.
IN VA70 DIGESTIBILITY:
Measurements:Classical in vivo balance has been applied. Six
Peul-peu1 sheeps were lodged in individual pens and fed twice
a day with diet including different levels of browses (cf
table 1) . Each tria1 took place during 15 days of adjustment
and 6 days of measurement.
Daily measurments involved dry
matter
intake,
and fecal collection.
Apparent dry matter,
organic
matter
and
crude
protein
digestibility
were
represented by the balance between their content in intake and
feces.
Calculation
methods:
The
calculation
method
assumed
the
additivity of
different
components of
the
ration.
The
digestibility of total ration is the sum of digestibility of
the different components multiplied by their percentage in the
ration. Browse digestion were estimated by difference.
IN SACCO DEGRADATION: (ORSKOV and Mc DONALD, 1979.; ORSKOV et
al., 1980. ; MICHALET-DOREAU et al., 1987.).
In sacco measurements was performed with nylon bag method.
It involved the placement of tree forage sample in a polyester
bag and direct incubation in the rumen of a cow. DM and N loss
during a given incubation time represents their degradation.
6
Animals
a n d
diets: 3
Young
fistulated
Gobra
bulls
averaging
250Kg of
body
weight
were
used
for
forage
incubation.
They were fed twice a day with rice straw (75
P100)
and
groundnut
cake (15 ~100). Minera1 block was
available in free choice as source of sodium, potassium,
phosphorus, copper zinc and cobalt.
Nylon bags:
They were
made
with Blutex (Tripette et
Renaud. France) nylon material (46pm pore size, 6 * 11 cm) and
heat sealed.
Experimental procedure:
3g of ground sample were put in
each nylon bag. The bag were heat sealed then incubated in
cattle rumen for 1, 4, 8, 24, 48, 72, 96 hours. The bags were
washed
and
beatten with
stomacher
to decrease
bacterial
contamination (Michalet-Doreau
and Ould-Bah,1989.) They were
washed again prior to drying at the oven (6O'C) The residual
bacterial contamination of the bags was substracted, assuming
a mean N bacterial residual contamination of 4 ~100.
Calculation:
The balance between initial and residual
content of the bag for dry matter and nitrogen represents
their degradation at a given incubation time.
TO estimate degradation parameters ORSKOV and MC DONALD,
(1979) mode1 were used:
D = a + b (l-e-ct) were D = degraded fraction at a
given incubation time (t); a = readily degradable fraction;
b = slowly degradable fraction.; c = degradation rate.
Parameters (a, b and c) were calculated with a non linear
mode1 of SAS (SAS, 1985).
bc
D T = a + -----
k = 0.04 specific for tropical forages
c + k
and cattle breeds (LECHNER-DOLL et a1 1990)
For -forage with slower degradation including a lag phase the
above mode1 has been adapted by DHANOA(1988)
bc
pf
= a + (b +
------ f ewkto)
to = lag time..
c + k
7
PEEDING TRIALS:: Influence on animal performances of rations
including different levels of tree forages was measured during
a 70 to 100 days tria1 including 15 days of preliminary
adjustement.
Groups of 12 sheeps 1 year aged averaging 22 kg of liveweight
were submitted to preliminary treatment against parasites, and
main infectious deseases occuring in sahelian zones.
Intake (offered minus refusal) of different ration component
were
daily
recordered.
Liveweight
change
were
monthly
evaluated by weighing the sheeps during two following days at
the same time.
RESULTS AND DISCUSSIONS
CHMICAL COMPOSITION OF TREE FORAGES:
The chemical composition of browse samples is described in
table 1. A high protein (CP) content, averaging 14 ~100 was
recordered.
Those results are in agreement with the datas
reportered in the litterature (LE HOUEROU, 1980.; LAMPREYet
al.,
1980.
and RIVIERE,
1978.)
and confirm the potential
protein source represented by tree forages during the dry
season when grass carpet CP content is bellow 5 pi00 and the
CP ratio of dried grasses on browses is close to zero.
A.
raddiana pods and leaves A. albida and C. procera
leaves are specially high in CP (> 15 pi00 in average).
Leguminous pods are not sensitive to phenological stage in
term of CP content. That is in agreement with our first
results (FALL, 1991). It was not the case for their leaves
which CP level was negatively influenced by age.
CP content in Calotropis and Adansonia varied within a
wide range. Those variations cannot be explained only by age
effects. Variety pressure needs to be checked. Guiera leaves
had the lowest CP content in a11 season of sampling.
Fiber content (NDF) were quite variable. The lowest level
were recordered in Calotropis (27%) while the highest one were
observed in Guiera leaves (72%).
-
Minera1 content of tree forages (see table 2) shows a
globally low phosphorus content. Most of samples were bellow
the critical level of 0.3 ~100 and the Ca/P ratio were often
8
bad exept for A. raddiana pods. SO browses cannot supply P
which is the most serious minera1 deficiency in the Sahel.
Copper and Zinc are among the main minera1 umbalance in the
Sahel. Browses bring only the minimum required (INRA, 1989): 4
to 7 ppm and 15 to 35 ppm respectively for copper and Zinc. SO
a
minera1
mixture is
advisable
for
minera1
deficiencies
prevention in the Sahel.
DIGESTIBILITY OF TREE FORAGES
RATION DIGESTIBILITY: (Table 3)
The digestibility of rations involving A. raddiana pods
and A.
digitata leaves were the highest one
(56 ~100 in
average),
followed by
ration
with
different
level of
Calotropis procera (50 pi00 in average). Rations with Guiera
leaves were the less digestible and that specie seemed to have
a negative
effect
in the digestive tract. The higher was
Guiera level in the ration the lower the digestibility. The ad
libitum level caused mortality of 3 over on 6 sheeps. The
tria1 was stopped after one week of adjustement.
The ration involving A. albida leaves was of low digestibility
while the one with the pods was intermediate.
OM and CP digestibility had the same variation profile.
DIPPERENCIAL DIGESTIBILITY OF BROWSES:
Browse
digestibility
are
presented in
table 4.
Although
variations between trials were high, the same hierachy was
recpected. Mimosacea pods were the most digested followed by
Adansonia digitata and Calotropis procera leaves. Guiera and
A. albida old leaves were of the lowest digestibility.
Variation between trials cari be explained in part by plant
age. Guiera leaves of june were more digested than that of
March. Another variation factor involves ration composition.
High level of Guiera does not seem to be accepted by sheep. It
cari be explained by a high level of tannins which fluctua-tes
from 4 to 11 ~100 DM (Kessler and Breman in_preparation; IEMVT
unpublished data).
In Calotropis leaves the between tria1 variations cannot be
explained by the plant age in the current stage of our
9
results. More investigations are needed to clarify the variety
effect.
Finally the role of browse level could be a variation source.
In the example of Adansonia leaves the same sample
DM and OM
digestibility varied within 20 points between 37 and 49 ~100
of the ration. In case of a non toxic specie a hundred ~100
browse diet is applicable to record information on intake and
palatability.
Current trials in LNERV give priority to the
highest browse levels (50 to 100 ~100).
SO observed variations in the in vivo tria1 results,
athought corresponding to litterature indications (see KESSLER
and BREMAN review in preparation), suggest more precautions in
sampling methods. One has to give large informations about
variety sampling date and site to comment on the results.
IN SACCO DEGRADATION OF TREE FORAGES:
(table 5 and 6;
figure 1 and 2).
Legume pods had stable and good degradation profile. More
of 70~100 of DM disappeared at 48 incubation time. A. albida
leaves are variable and sensitive to age. Young leaves were
highly degraded while old one were of poor intra-rumenal
degradation (Fall, 1991). A. raddiana leaves and pods had a
comparable
and
good
degradation
profile.
Adansonia
and
Calotropis
leaves are the most degraded sample (Deg 48h >
80~100) while guiera leaves were of poor degradation (Deg 48h
< 40 plO0).
Legume pods as well as Adansonia and Calotropis leaves of
high rumen degradation are potential N source for ruminants.
Browse
degradation profile is
influenced by chemical
composition.
Ce11
wall
components
play a
negative
role
(Bammualin et al.,
1980
reported by
Nitis,
1992.).
Particularly N location into ce11 wall (Krishnamoorthy et al.,
1982; Sanderson and Wedin 1989.). The major part of digestible
N is located in ce11 solubles. ADFN is not important (less
than 20~100 of total N) in tropical browses but it plays a
significant (PcO.05) role in N degradability (Fall and Doreau
1993, in press). Our results confirm that as Guiera leaves, of
highest ADF content, were the less degradable. Also the role
10
of tannins is emphasized (Mc Leod, 1974.; Diagayete, 1981.;
Reed et al.,
1990.
and Leinmuller et al.,
1991.).
Plant
tannins
depress
browse
digestibility.
Differences i n
litterature reports cari be explained in that the reaction
tannins-proteins
is governed
by multiple
factors such as
tannin type, and level in feeds. Hydrolysable tannins cari be
modified by digestive enzymes and thus, do not depress CP
digestion
while
condensed
one
precipitate
with
proteins
forming
indigestible
complexes.
Their
effect in
protein
balance is negative.
Tanins level less 3 pi00 (NITIS, 1992.)can give benefit in
good quality proteins digestion by protecting them, for direct
absorption in the small intestine. Above that level occurs a
phenomenon of precipitation which makes them indigestible.
Tanin analysis are in progress in IEMVT for checking of their
effect upon degradation.
INFLUENCE OF TREE FORAGES ON GROWING SHEEP PERFORMANCES:
Five
trials
were
carried
out to
study
secondary
productivity of A, albida pods, G, senegalensis, C. procera
and A. digitata leaves.
In tria1 5 (see table 7) G. senegalensis leaves were
compared to A. albida pods. The average daily intake was close
between the two groups and superior to the control one. A.
albida
pods
group was
significantly
(PeO.05) higher in
liveweight gain compared to Guiera one and the two groups were
significantly
different compared
to the unsupplemented one
which was at maintenance level. Guiera group were slightly
higher in performance while A. albida pods ration allowed a
semi-intensive growing.
It cari be compared to Glyricidia
sepium
which
allowed
a daily liveweight change
(LWC) of
4Og/day (Smith and Van Houter, 1987.) and Albizia zygia, 800g
/ day giving a LWC of 48g a day (Bouche1 et al., 1992.) while
Konig et al. (1992) reportered a negative effect for Atriplex
nummularia leaves at the level of 25 to 75 ~100 of the diet in
sheep performances wihch have lost 31 to 93g a day.
11
Guiera was compared to C. procera leaves in tria1 7 (see
table 8). Calotropis group was superior in intake and animal
performances.
Animal performances were higher for Guiera in tria1 5
compared to tria1 7. That result has been suprising as Guiera
intake were superior in the last trial. It cari be explained by
the different nature of the basa1 diet made of early dry
season bush hay of better quality compared to rice straw. A
higher total DM intake
(89 vs
64 g/Kg P"=75)
was
also
recordered.
C. procera at the level of 1.5 pi00 allowed semi-intensive
growing of Young sheep. Sundrying seems to alleviate eventual
toxicity of that tree forage wihch is well consumed without
any sign of toxicity.
Objectives of tria1 3a, 3b and 8 (see tables 9, 10, and 11
respectively)
were to
study
the
influence of
Adansonia
digitata leaves on Young sheep performances.
We had many
health problems in tria1 3a; that's why a repetition was done
in tria1 3b. Animal performances were 16 and 27g per day
respectively for the level 100 and 200g per day. They were
significantly superior (PKO.05) compared to the control group
which was loosing 56g/day. The 300g level, expected to be
higher, was close to the 200g one in term of liveweight change
(21 vs 27g /day). The tria1 duration
(70 days) might be a
fimiting
factor
for
maximum
performance
record as
the
liveweight curve was in ascending phase when it stopped. Those
values are close to that of Alchomea cordifolia (48 ~100 of
the diet) wich gave an average LWC of 25g (Kouonmenioc et al.,
1992.)
CONCLUSION:
.Browses represents the only CP source available during the
dry season for ruminants in pasture based systems of the dry
tropics.
Although their nutrient content cari be high, the
digestive utilisation may vary according to species, age, and
plant part. A. albida and A. raddiana pods at the level of 15
to 25 pi00 cari achieve semi intensive fattening ( 16 to 30 g /
day) in sheeps while C. procera and A. digitata leaves of
12
higher nutrient content cari be given to sheep up to 30 ~100
level in the diet,
in intensive fattening program.
Current
trials involve evaluation of intake and liveweight change of
ration with higher proportion of tree forage for toxicity
screening.
BIBLIOGRAPHY
AOAC,
1975.
Officia1
methods of
analysis.
12th ed.
A.O.A.C., Washinaton, DC: 152-169.
BOUCHEL D., BODJI, N.C. et KOUAO, B.J. 1992. Effet de la
complémentation d'une ration de base de qualité médiocre par
Albizia zygia sur le comportement alimentaire et la croissance
d'ovins Djallonké. In: The complementaritv of feed resources
for animal production in Africa. Stares J.E.S., Said A.N. and
Katesile J. ILCA Addis Abeba. pp 113-125.
DHANOA, W. S., 1988. Research note on the analysis of
dacron bag data for low degradability feeds. Grass and Foraae
Sci., 43: 441-444.
DIAGAYETE M., 1981. Untersuchungen zur erweiterung der
kenntnisse
über
den
futterwert
wastafrik a
nisher
futterpflangen.
Dissertation zur erlarauna des srades eines
doktor der aararwissenschaften, Universitat Hohenheim: 135~.
FALL, S-T.,
1991. Digestibilité in vitro et dégradabilité
in
sacco
de ligneux fourragers disponibles
sur pâturages
naturels au Sénégal. Premiers résultats. Rev. Elev. Med. Vet.
Pays Trop. 38 (3): 345-354.
FALL, S-T.
and MICHALET-DOREAU,
B.
1993.
Comparative
rumina1
nitrogen
degradability of
tropical
browse
and
temperate forages. Proceedinas of the XVII th International
Grassland Conqress. Australia New Zealand. February 1993, In
Press.
GOERING, H-K,
and VAN SOEST, P.J.,
1970.
Forage fiber
analysis
(Apparatus,
Reagents,
Procedures
and
some
applications) Aariculture Handbook 379 US Dot of Aariculture.
2op.
-
GUERIN, H., 1987. Alimentation des ruminants domestiques
sur pâturages naturels sahéliens et sahélo-soudaniens: Etude
methodologique dans la region du Ferlo au Sénégal. These de
Doctorat ENSA Montnellier 211~.
13
IN=, 1989. Ruminant nutrition: Recommended allowance and
Feed tables. Jarriqe R. ed. INRA France.
REARL, L-C., 1982. Nu-trient requirement of ruminants in
developping countries.
International Feed Institute, Oreaon,
UT, USA, 381 p.
KONE, A-R.,
1987. Valeur nutritive des ligneux fourragers
des
régions
sahéliennes
d'Afrique
Occidentales.
Recherche
d'une méthode simple d'estimation de la digestibilite et de la
valeur azotée. Thèse de Doctorat 3ème cvcle.' Univ. Paris VI.
131 p.
KONIG, R.C.W., BECKET, K., BENJAMIN, R.W. and SOLLER, H.
1992. Performance of sheep and goats with offspring on semi-
arid saltbush (Atriplex nummularia) - grassland ranges in the
early dry season. In: The comnlementaritv of feed resources
for animal nroduction in Africa. Stares J.E.S.. Said A.N. and
Kateaile J.A. editors. ILCA Addis Ababa Ethiopia. pp 63-74.
KOUONMENIOC, J., LACOSTE, A. et GUERIN, H, 1992. Etude de
l'influence de
quatre
fourrages
ligneux
sur
l'evolution
pondérale des ovins de la race naine de l'Afrique de l'Ouest.
In:
The
comnlementaritv
of
feed
resources
for
animal
production in Africa. Stares J.E.S., Said A.N. and Kateaile
J.editors. ILCA Addis Ababa. Ethiopia. pp 97-110.
KRISHNAEIOORTHY,
U.,
MUSCATO, T-V.,
SNIPPEN, C-J., VAN
SOEST, P.J. 1982. Nitrogen fractions in selected feedstuffs.
Journal of Dairv Science 65: 217-225.
LANPREY, H-F.,
HKRLOCKER, D. J., PIELD, C.R. 1980. Report
on the satage of knowledge of browse in West Africa. In: Le
Houerou ed. Browse in Africa: The current stase of knowledqe.
Addis Abeba. ILCA, 1980. pp 33-54.
LECHNER-DOLL, H., RUTAWENGA, T., SCHWARTZ, H-J., SCHULTKA,
W. and ENGKLHART, V. W. 1990.
Seasonal changes of ingesta
mean retention time and forestomach fluid volume in indigenous
camel,
cattle, sheep and goats grazing a thornbush Savannah
pasture in Kenya. J. of Aaric. Sci. Camb., 115: 409-420.
LE HOUEROU, H.N. 1980. The role of browse in the sahelian
and sudanian zones. In: H.N.
Le Houerou editor. Browse in
Africa: The
current
staqe o f
knowledae.
International
Livestock Center for Africa. pp 83-100.
LEINMJLLW, E., STEINGASS, H., MENEE, K-H., 1991. Tannins
in ruminant feedstuffs. Anim Res and Develon., 33: 9-62.
HC LEOD, H-N-, 1974. Plant tannins- Their &le in forage
quality.Nutr. Abstr. and Rev., 44: 803-815.
WICHALET-DOREAU,
B. and OULD-BAH, W-Y., 1989., Estimation
of the extend of bacterial contamination in bag residues and
it's influence on in sacco measurements of forage nitrogen
14
degradation in
the
rumen. In:
Proceedinqs of
the XVI
International Grassland Concrress: 909-910.
MICHALET-DOREAU, B., VERITE, R. et CHAPOUTOT, P., 1987.
Méthodologie de mesure de la dégradabilité in sacco de l'azote
des aliments dans le rumen. Bull. Tech. CRZV Theix, INRA
France. 69: 5-7.
NITIS, 1. M., 1992. Fodder shubs and trees in small holder
farming
systems in
the
tropics. In:
Natural
Resources
Develonment and Utilization. R. De Jona, T. Nolan and J. Van
Bruchem editors. EEC. IAC. Wageningen. The Netherland. pp 36-
51,
ORSKOV, E. R., DEB HOWELL, F. D. and MOULD, F., 1980. The
use of nylon bag technique for the evaluation of feedstuffs.
Trop. Anim. Prod., 5: 195-213.
REED, J.D., SOLLER, H. and WOODWARD, A., 1990. Fodder tree
and straw diet for sheep: intake, growth, digestibility and
the effect of phenolics on nitrogen utilisation. Anim. Feed
Sci. and Technol., 30: 39-50.
RIVIERE, R.
1978.
Manuel d'alimentation des ruminants
domestiques en milieu tropical. IEMVT Maisons-Alfort Ministère
De La Coonération France.
SANDEXSON, 54. A., WEDIN, W-F.,
1989:
Nitrogen in the
detergent fibre fractions of temperate legumes and grasses.
Grass and Foraae Science 44: 159-168.
SS,
1985. SAS user's guide: Statistics. Cary, NC: SAS
Institute Inc.
SMITH, O-B,
et VAN HOUTERT,
M.F.J.,
1987.
La valeur
fourragere de Glyricidia sepium. Revue Mondiale de Zootechnie.
62: 57-68.
VON MAYDELL, H-J.,
1983.
Arbres et arbustes du Sahel.
Leurs
caractéristiques et
leur
utilisation.
Publie nar
l'office
Allemand de la Coopération Technioue (GTZ) 2eme
édition 531~.
ACKNOWLEUGEMENTS:
The authors are indebted to Massamba Diop and Bernard
Ahokpe
for their technical support in feeding trial, to
Bassirou Diaw for assistance in nylon bag studies and to M.
Dione for the supply in plant material. --
This work has been jointly funded by IFS (Grant No B/1107-
02) and EEC (ST2.A.75-IRL).
TABLE 1
CHEMICAL COMPOSITION OF TREE FORAGES
Maan Value g/ Kg DM
@ange)
SPECIES
PLANT-PART
NO
MS
MM
CP
NDF
ADÇ
Li
4cocia albida
Pods
5
920
44
113
385
221
(960-894)
(38-50:
[104-122)
(388-390)
(120-275)
Leaves
4
918
99
152
396
296
(896-955)
(88-1091
1128-194)
(315-476)
(191-401)
kocia roddiana
Pods
7
913
61
176
471
341
144
(896-961)
(49-7 1:
1737-205) (418-523)
(375-407)
(139-148)
Leaves
17
913
121
182
371
285
190
(864-959)
(98-180)
'125-220) (346-363)
:229-334)
(181-216)
hiera senegalensis
Leaves
30
915
75
109
615
517
98
/
c883-958)
(48-151)
(70-122) (574-728)
1487-615)
(61-150)
rdansonia digitata
Leaves
9
896
110
102
487
272
116
1872-928)
(56-l 39)
(52-138) (521-452)
1157-360)
(61-171)
alotropis procera
Leaves
19
882
200
159
290
217
116
1854-908)
(68-242)
(242-68) (276-302)
199-241)
(81-109)
(379-151)
(68-242)
Table 2:
CHEhiîCAL COMPOSITION OF TREE FORAGES
Mean value
(range)
‘owse species
Ca
P
CU
Zn
N a
K
g/Kg DM
g/KgDM
ppm
ppm
ppm
ppm
cacia albida pods
3.39
1.63
4.5
19.1
953
1.4
(2.4-4.4)
(1.47-1.91)
cacia albida leaves
17.51
1.66
7.3
29.3
832
1.1
(14.9-24.11)
(1.33-2.01)
(6.7-7.9)
(27.5-31.2)
(486-1178)
(0.9-1.3)
mcia raddiana pods
8.12
3.35
3.4
38.5
4 1
1.6
(1.83-8.12)
(1.82-8.74)
(2.7-4)
(29.7-50.9)
(15-64)
(1.2-1.8)
cocia raddiana
laves
22.3
1.67
3.7
29
448
1.2
(15.3-31.7)
(1.0-2.8)
(2.2-6.7)
(22.7-41.9)
(116-947)
(0.6-1.5)
lera senegalensis
q ves
15.2
1.4
1 0
29
315
0.7
/
(8.2-21.2)
(0.5-1.8)
(5.0-19.7)
(13.7-64.3)
(96-52 1)
(0.3-1.1)
dansonio digitoto
aves
24.9
2.29
8.6
27.6
769
96
(5.3-39.6)
(1.0-6.10)
(7.5-10.5)
(25.9-3 1 .O)
(449-1352)
(84-65)
alotropis procera
‘aves
26.13
2.2
6.7
36.4
8771
3.5
(13.8-49.4)
(O-6-3.9)
(4.0-8.0)
(19.6-54.3)
(5833-12213)
(2.0-6.9)
TABLE 3:
W VIVO WGESTIBILITY O F DtETS P. 100
FD
IDIET CDU’0NENT P. 100
E T DIGES .ITY P.100
1
IGESTIBILITY NO
BROWSES ’
GRCUNDNUT
IICE
IUSH
DM
OM
CP
I
CAKE
;TRAM
IAy
4 9 8
A c a c i a obida o!d Ieoves
5 0
1c
4c
4o.c
4 2 . 9
26.4
4 9 9
Acacia atbida nature fruits
27
ll.
60
53.4
57.3
69.8
16
Acacia raddiana nature fruits
52
11
37
5 7 . 1
58.6
6 6 . 1
17
Acacia raddiana nature fruits
50
1c
40
55.5
57.3
6 1 . 4
500
Guiera serwgatansis baves
33
16
5 1
43.9
47.8
52.1
4
II
a
a
8 4
6
8
a
a 4
4 9 . 1
4 7 . 7
5 8 . 7
5
16
8
76
7
15
a
77
47.1
42.7
53.0
23
15
10
75
5 2 . 7
5 5 . 4
5 1 . 4
1 8
42
1 2
48
4 3 . 4
46.0
43.3
1 9
II
1 0 0
10.3
10.8
- 7 0 . 0
2 0
II
75
25
3 5 . 7
35.7
2 5 . 4
3
:alotropis procera lsaves
9
9
a2
50.9
l2
t,
11
1 0
7 8
50.6
9
PI
1 2
1 2
76
4 8 . 7
50.5
65.8
22
8,
1 6
11
73
5 1 . 4
53.5
67.1
1
0,
17
8
75
5 5 . 9
1 0
II
20
12
69
4 9 . 2
50.2
59.2
26
Adamonia dtgitata Iaaves
37
1 9
44
62.7
66.1
67.1
2 7
Adansonia digttata Iaaves
49
1 0
4 1
5 2 . 3
58.3
6 6 . 8
TABLE 4:
BROWSE DIGESTIBILITY (DFFERENCIAL
METH~D OF CALCULATION)
DIET COMPONENT P.100
BF
FIOWSE DIGESTIBLITY P.' 1
D IGESTIBILITY
1 BROWSES
Gf<OUNDNUT -7 CE
BI USH
DM
OM
CP
t NO
DATE
CAKE
S TRAW JAY
498
Al cocia albida old Ieavas
50
1 0
40
28.0
31.2
14‘0
499
A cacia albida nature fruits
27
13
60
65.9
70.7
100.0
77.3
1 6
sacia
A.
raddiano nature fruits 48
11
37
62.1
64.0
1 7
A l :acia raddiana nature fruits 50
10
40
61.2
63.2
69.2
500
Gl riera senegalensis
leaves
33
16
5 1
24.8
30.6
4 ,ARCH 88
II
8
8
84
59.0
46.0
37.7
6
MARCH 88
8
8
84
5
MARCH 88
16
8
76
40.6
18.6
33.0
7
MARCH 88
II
15
8
77
23
APRL 88
t,
15
10
75
70.6
68.0
1
1 8
4PRL 88
42
12
48
33.3
40.7
29.3
1 9
APRIL 88
,t
100
10.3
10.8
-70.0
20 APRIL 88
75
25
17.4
18.0
16.6
3 APRIL 88
C alotropis procera leaves
9
9
82
II
2
APRIL 88
11
10
78
,t
9 DECEM 88
12
12
76
35.5
39.1
70.6
II
22 JUNE 88
16
11
73
59.8
52.5
67.6
1
JUNE 88
17
8
75
1 0 DECEM 88
20
12
69
50.5
57.5
61.5
26 SEPT 88
A dansonia digitata Ieaves
37
19
44
70.5
71.0
100.0
27 SEPT 88
b idansonia digitata Ieaves
49
10
41
51.4
57.1
96.3
-
TABLE 5
IN SITU DM DEGRADATION OF TREE FORAGES
r
INCUBATION TIME ft10u r s )
-
NO
l-
TREE FORAGES
DIG
2
4
8
24
48
72
96
Calotropis procera feuilles
5
43.2
45.6
55.7
80.8
92.9
93.3
93.6
Adonsonia digitata feuilles
1
29.3
29.7
30.9
52.8
78.4
83.0
82.8
Acacia raddiana feuilles
3
34.7
35.1
36.7
50.6
66.9
72.4
73.3
Acacia raddiana feuilles
2
34.0
34.9
39.9
58.3
69.3
74.2
75.3
4cacia albida feuilles
2
59.0
65.0
69.0
kacia albida fruits
1
71.0
74.0
76.0
Liera senegalensis feuilles
a
31.4
31.3
34.8
39.6
41.2
44.3
* FALL
1991
TABLE 6
NITROGEN DEGRADATION IN TREE FORAGES
P 1 0 0
r
II\\ICUBATIC
-
rs>
‘REE FORAGES
2
4
8
2 4
4 8
7 2
9 6
9 7 . 5
Zalotropis procera leaves
6 1 . 7
6 3 . 2
7 3 . 0
8 9 . 6
96.6
9 7 . 2
8 5 . 6
ddansonia digitata leaves
21.1
2 5 . 0
26.1
4 4 . 6
8 0 . 5
8 5 . 9
J
7 8 . 7
4cacia raddiana leaves
2 1 . 6
2 1 . 3
2 1 . 7
3 9 . 9
6 7 . 5
7 6 . 3
9 0 . 8
Acacia raddiana pods
5 6 . 5
5 6 . 8
6 0 . 9
7 7 . 2
8 6 . 0
9 0 . 0
Acacia albida leaves
5 6 . 0
6 2 . 0
6 8 . 0
7 5 . 0
Acacia albida pods
6 0 . 0
6 9 . 0
7 1 . 0
7 2 . 0
3 7 . 9
Guiera senegalensis leaves
1 8 . 4
2 2 . 2
2 3 . 0
2 3 . 4
2 8 . 3
3 3 . 3
TABLE 7: Influence of Acacia albida pods and Guiera senegalensis
leaves on growing sheep performances
SHEEP LOTS
I
II
Ill
:ontrol)
ANIMAL DIETS: (Kg)
ad
ad
Rice straw:
F
libitum
libitum
Peonut cake:
C l
0.1
0 . 1 2 5
Acacia albida pods:
C2
DRY MATTER INTAKE:
l adlibitum0.10.2 -
Guiera senegalensis leaves:
C2
0 . 2
F
3 6 9
3 4 2
4 1 3
g/head/day
Cl
9 0
9 1
1 1 8
c 2
1 7 4
1 6 6
TOTAL: (g)
6 3 3
5 9 9
5 3 1
TOTAL: g/KgPO .7 5
6 3
6 4
5 4
LIVEWEIGHT:
Starting: (Kg)
20.1
18.9
2 1 . 4
End: (Kg)
23.1
2 0 . 8
2 1 . 0
Average: (Kg)
2 1 . 6
1 9 . 8
2 1 . 2
Total liveweight gain: (Kg)
3.0
1.9
- 0 . 4
Daily liveweight gain: (g)
4 0 . 0
2 5 . 0
- 5 . 0
TABLE 8: Influence of Calotropis procera and Guiera senegalensis
leaves on growing sheep perfomances
SHEEP LOTS
A
B
C
control
4NIMAL DIETS: (Kg)
ad
ad
ad
3ush hay:
F
libitum
libitum
libitum
‘eanut cake:
Cl
1 0 0
1 0 0
1 0 0
Zalotropis procera leaves:
c 2
-
1 5 0
Juiera senegalensis leaves:
1 5 0
-
IRY MATTER INTAKE:
F
7 1 6
8 2 4
7 4 3
g/head/day
Cl
8 9
9 8
9 4
c 2
1 0 5
1 2 6
TOTAL: (g)
9 1 0
1 0 4 8
8 3 6
TOTAL: g/Kg P0.75
8 4
9 3
8 0
LIVEWEIGHT:
Starting: {Kg)
2 2 . 0
2 2 . 6
2 1.6
End: (Kg)
2 5 . 7
2 7 . 9
2 3 . 9
Average: (Kg)
2 3 . 8
2 5 . 2
2 2 . 7
Total liveweight gain: (Kg)
3.7
5 . 2
2 . 3
Daily liveweight gain: (g)
4 0 . 0
5 9 . 0
2 5 . 0
TABLE 9: Influence of Adansonia digitata leaves
on growing sheep performances (tri:al No sa)
SHEEP LOTS
II
Control
ANIMAL DIETS: (g)
Rice straw:
F
rd libitum
ad libitum
Peanut cake:
Cl
7 5
1 5 0
Adansonia digitata leaves:
c2
2 0 0
0
DRY MATTER INTAKE:
F
4 5 0
5 1 4
g/head/day
Cl
1 0 6
1 5 7
c 2
191
0
TOTAL: (g)
7 4 7
6 7 1
TOTAL: g/KgPO .7 5
6 9
71
LIVEWEIGHT:
Starting: (Kg)
2 2 . 0
19.8
End: (Kg)
2 5 . 7
2 0 . 0
Average: (Kg)
2 3 . 8
19.9
Total liveweight gain: (Kg)
3 . 7
0.2
Daily liveweight gain: (g)
4 0 . 0
1 .o
TABLE 10: Influence of Adansonia digitata on growing sheep
performances
(triai n03b)
;HEEP LOTS
I
II
III
contra1
4NIMAL DIETS: (g/head/day)
ad
ad
ad
iice straw: F
F
libitum
libitum
libitum
‘eanut cake:
Cl
1 0 0
1 0 0
1 0 0
Adansonia digi tat a leaves:
c 2
1 0 0
2 0 0
0
DRY MATTER INTAKE:
C
3 9 4
4 2 6
4 1 6
g/head/day
Cl
91
9 2
9 3
C2
8 7
1 7 6
0
TOTAL: (g)
5 7 2
6 9 4
5 0 9
TOTAL: g/Kg P0.75
56.1
6 6 . 7
5 5 . 7
LIVEWEIGHT:
Starting: (Kg)
2 1 . 7
2 2 . 0
2 0 . 5
End: (Kg)
2 2 . 6
2 3 . 5
17.7
Average: (Kg)
22.1
2 2 . 7
19.1
Total liveweight gain: (Kg)
0.9
1.5
- 2 . 8
Daily liveweight gain: (g)
16.4
2 7 . 3
- 5 6 . 0
Tlhl
l -
.
4.
,.-Il
.._._ -_
-1
I
J-----!-
-II-?,-,-
-._
IABLL I I :
inriuence 01 ,4oonson1u
uigirara o n
growing sheep performances (tria1 No 8)
SHEEP LOTS
Il
ANIMAL DIETS: (g/head/day)
Rice straw:
F
ad libitum
Peanut cake:
Cl
1 5 0
Adansonia digitata leaves:
c 2
3 0 0
DRY MATTER INTAKE:
F
3 0 9
g/head/day
Cl
1 2 4
c 2
2 7 3
TOTAL: (g)
7 0 6
TOTAL: g/Kg P0.7 5
7 5
LIVEWEIGHT:
Starting: (Kg)
1 8 . 4
End: (Kg)
19.9
Average: (Kg)
2 2 . 5
Total liveweight gain: (Kg)
1.5
Daily liveweight gain: (g)
21 .o
Figure 3 - in situ degradation of Browses
DM degradation ~100
?2#
80
---._---.-_-.-_- _____
..---- ----_-~--_--._
t
t
t
I
I
l
t
2
4
8
24
48
72
96
h3Jbation time (t-l)
- C.prOcera lea
+ A
.
digitAta ” +- A.raddieim ” -0- A.risiddi8nis po
--Y& Aalbida leav -$- A . albida p o d * G . senegalens
FïQure 4 -
N degradation in browses
in situ dsgradation plO0
120
0:’
1
1
t
t
2 4
a
24
48 .
72
96
lrcutxtion time (h)
-- c.proccr A 1
--I- A.dlQitOi~ L
;ti- A.rBddiarm L ++- A.reddifmEJ P
-x- A.albid3 L
il- Aalbid3 P
--A-- G.sensgalonJi
u..”
MINISTERE DU DEVELOPPEMENT
RURAL ET DE L’HYDRAULIQUE
INSTITUT SENEGALAIS DE RECHERCHES
A G R I C O L E S ( I . S . R . A . )
DEPARTEMENT DE RECHERCHES SUR LES
PRODUCTIONS ET LA SANTE ANIMALES
LABORATOIRE NATIONAL DE L’ELEVAGE
ET DE RECHERCHES VETERINAIRES
B.P. 2057
D A K A R - HANN
N U T R I T I V E V A L U E O F S O M E TREE
FOR2iGES
S P E C I E S AVAILABLE I N
Si%HELIi%N PASTURES,
BY
FALL-TOURE, s.,
RICHARD, D. ,FRIOT, D., NOLAN, T-l, CONNOLLY,
J.2 and SALL, Ca3 .
ISRA-LNERV BP 2057 DAKAR SENEGAL.
2 TEAGASC ATHENRY CO. Galway. IRELAND.
UNIVERSITY COLLEGE DUBLIN.
Statistics Dept. UCD 4 Dublin
IRELAND
31SRA CRZ DAHRA SENEGAL
R E F . N042/RES.AL.
NOVEMBRE 11992.
2
ABSTRACT :
Quality of some tree forages from West Africa, Acacia albida,
Acacia
raddiana
leaves
and
pods ,
Guiera
senegalensis,
Calotropis procera and Adansonia digitata leaves was studied.
Applied
methodology
involved
chemical
analysis, in
vivo
digestibility, in
sacco
degradation,
intake
and
animal
performances
measurements of
rations
including
different
levels of browses.
Results emphasize the high digestible nutrients content of
Mimosacea pods, C. procera and A. digitata leaves while G.
senegalensis and A. albida old leaves were of poor nutritive
value. Feeding trials involving A. albida pods , C. procera,
A.
digitata and G.
senegalensis
leaves
confirmed chemical
analysis and in vivo digestibilities results. The aptitude to
improve energy and nitrogen level of rations for sheep is high
for A.
albida pods, C. procera and A. digitata leaves. G.
senegalensis at a level superior to 40 pi00
played a negative
role in ration digestion because of low digestibility (30
PlOO), low rumen degradability (deg 48h < 40 ~100) and high
tannin content.
KEY WORDS:
Sahelian pastures, Nutritive value, Tree forages,
Acacia albida, Acacia raddiana,
Adansonia digitata, Guiera
senegalensis, Calotropis procera.
VALEUR NUTRITIVE D'ESPECES FOURRAGERES ARBUSTIVES DISPONIBLES
SUR PATURAGES SABELIENS
Par
FALL-TOURE S., RICHARD D., FRIOT D., NOLAN T.', CONN&LY J.2
and SALL C3.
3
RESUME
La qualité d'arbustes fourragers d'Afrique de l'Ouest, les
feuilles et gousses d'Acacia albida et Acacia raddiana, les
feuilles de Guiera senegalensis, Calotropis procera et celles
d'Adansonia digitata est étudiée.
La
méthodologie
appliquée
porte
sur
les
analyses
chimiques, la digestibilité in vivo, la dégradation in sacco,
et la mesure de l'ingestibilite et des perfomances animales de
rations comportant différents niveaux de ligneux fourragers.
Les résultats mettent en évidence la haute teneur en
nutriments
digestibles
des gousses
de Mimosaceae et des
feuilles de Calotropis procera ainsi que celles d'Adansonia
digitata alors que les feuilles agees d'Acacia albida et
celles de Guiera senegalensis ont eu une valeur nutritive
médiocre.
Ces
résultats ont été confirmés par les essais
alimentaires.
Les gousses d'A.
albida et les feuilles de C.
procera et A. digitata données en complément aux fourrages
pauvres à de jeunes moutons ont permis leur croissance semi-
intensive. G. senegalensis à un niveau superieur à 40 ~100 de
la ration a joué un rôle négatif sur la digestibilité de la
ration probablement a cause d'une faible dégradation intra-
ruminale et d'une teneur élevée en tannins.
PKYrs CLES:
Paturages
sahéliens,
Valeur nutritive, Fourrages
arbustif, Acacia albida, Acacia raddiana, Adansonia diqitata,
Guiera seneqalensis, Calotropis procera.
INTRODUCTION:
Sahelian soils are well reputed for their deficiencies in
organic matter and phosphorus. Pastures are more affected by
drought and soi1 degradation than cultivated lands which are
yearly
improved by
manure
and or
fertilizer.
Thus a
proliferation of plant indicators like Calotropis procera or
Zornia qlochidiata is observed in the Sahel. During ten past
4
years, the situation has been specially enhanced by bush fire
and predators like locust.
The aerial part of pastures, made
of trees and shrubs plays a significant role in ecosystem
maintenance as it has a great capacity of regeneration and
drought resistance.
Most of them are ever green and are an
invaluable
feed
resources
available
a11
over
the
year.
Therefore, browses
are the main ruminants nutrients source
providing nitrogen minerals and vitamins during the dry season
(Le Houerou 1980).
Although the behaviour of ruminants differs according to
seasons and plant species, browses represent up to 30, 70 and
80 pi00 of cattle sheep and goat diet respectively during the
dry season (Guérin, 1987.).
600
species
has
been
identified as
potential
feed
resources for cattle, sheep and goats (Von Maydell, 1983., Le
Houerou
1980).
Available résults gives informations about
their palatability and chemical composition. The high nitrogen
content of tree forages is well known (Riviere, 1978.; Le
Houerou, 1980.; Kearl, 1982.; Koné, 1987.). That nitrogen may
not be available in the digestive tract (Fall, 1991.) and data
about digestibility and influence on animal performances are
scarce. That topic was described as a "top priority subject in
African livestock nutrition todayVt (Le Houerou, 1980.)
We intended to evaluate nutritive value of Acacia albida
and Acacia raddiana leaves and pods,
Guiera
senegalensis,
Calotropis
procera
and
Adansonia
digitata
leaves.
Those
species
are
popular
and
well
represented in
sahelian
ecosystems. A. albida and A. raddiana pods are sold in some
west African markets and CI
procera has been increasingly
available in sahelian pastures as a consequence of drought and
soi1 degradation .
MATWIALS AND MEZHODS:
S!CUDY SITE:
In vivo measurements has been performed in Dahra an ISRA
station located 270 km in the north east of Dakar in the
sahelian zone of Senegal at 15"North,
and 15OWest Longitude.
5
Average rainfall was 340 mm during past twenty years ranging
from 570
to 110 mm.
SAMPLE COLLECTION AND PREPARATION:
Tree forage samples has been collected in Dahra zone,
sundried and stored for in vivo trials.
For each specie a
subsample has been ground to pass lmm sieve for chemical
analysis .
CHEMICAL ANALYSIS:
Chemical analysis was carried out in LNERV-ISRA Station
laboratory of Dakar. They involved dry matter, crude protein,
ash, calcium and phosphorus evaluation (AOAC 1975). NDF, ADF
and lignin were analysed according to Goering and Van Soest,
(1970) and Sodium, potassium, copper and zinc were determined
with atomic absorption spectrosphotometry.
IN VA70 DIGESTIBILITY:
Measurements:Classical in vivo balance has been applied. Six
Peul-peu1 sheeps were lodged in individual pens and fed twice
a day with diet including different levels of browses (cf
table 1) . Each tria1 took place during 15 days of adjustment
and 6 days of measurement.
Daily measurments involved dry
matter
intake,
and fecal collection.
Apparent dry matter,
organic
matter
and
crude
protein
digestibility
were
represented by the balance between their content in intake and
feces.
Calculation
methods:
The
calculation
method
assumed
the
additivity of
different
components of
the
ration.
The
digestibility of total ration is the sum of digestibility of
the different components multiplied by their percentage in the
ration. Browse digestion were estimated by difference.
IN SACCO DEGRADATION: (ORSKOV and Mc DONALD, 1979.; ORSKOV et
al., 1980. ; MICHALET-DOREAU et al., 1987.).
In sacco measurements was performed with nylon bag method.
It involved the placement of tree forage sample in a polyester
bag and direct incubation in the rumen of a cow. DM and N loss
during a given incubation time represents their degradation.
6
Animals
a n d
diets: 3
Young
fistulated
Gobra
bulls
averaging
250Kg of
body
weight
were
used
for
forage
incubation.
They were fed twice a day with rice straw (75
P100)
and
groundnut
cake (15 ~100). Minera1 block was
available in free choice as source of sodium, potassium,
phosphorus, copper zinc and cobalt.
Nylon bags:
They were
made
with Blutex (Tripette et
Renaud. France) nylon material (46pm pore size, 6 * 11 cm) and
heat sealed.
Experimental procedure:
3g of ground sample were put in
each nylon bag. The bag were heat sealed then incubated in
cattle rumen for 1, 4, 8, 24, 48, 72, 96 hours. The bags were
washed
and
beatten with
stomacher
to decrease
bacterial
contamination (Michalet-Doreau
and Ould-Bah,1989.) They were
washed again prior to drying at the oven (6O'C) The residual
bacterial contamination of the bags was substracted, assuming
a mean N bacterial residual contamination of 4 ~100.
Calculation:
The balance between initial and residual
content of the bag for dry matter and nitrogen represents
their degradation at a given incubation time.
TO estimate degradation parameters ORSKOV and MC DONALD,
(1979) mode1 were used:
D = a + b (l-e-ct) were D = degraded fraction at a
given incubation time (t); a = readily degradable fraction;
b = slowly degradable fraction.; c = degradation rate.
Parameters (a, b and c) were calculated with a non linear
mode1 of SAS (SAS, 1985).
bc
D T = a + -----
k = 0.04 specific for tropical forages
c + k
and cattle breeds (LECHNER-DOLL et a1 1990)
For -forage with slower degradation including a lag phase the
above mode1 has been adapted by DHANOA(1988)
bc
pf
= a + (b +
------ f ewkto)
to = lag time..
c + k
7
PEEDING TRIALS:: Influence on animal performances of rations
including different levels of tree forages was measured during
a 70 to 100 days tria1 including 15 days of preliminary
adjustement.
Groups of 12 sheeps 1 year aged averaging 22 kg of liveweight
were submitted to preliminary treatment against parasites, and
main infectious deseases occuring in sahelian zones.
Intake (offered minus refusal) of different ration component
were
daily
recordered.
Liveweight
change
were
monthly
evaluated by weighing the sheeps during two following days at
the same time.
RESULTS AND DISCUSSIONS
CHMICAL COMPOSITION OF TREE FORAGES:
The chemical composition of browse samples is described in
table 1. A high protein (CP) content, averaging 14 ~100 was
recordered.
Those results are in agreement with the datas
reportered in the litterature (LE HOUEROU, 1980.; LAMPREYet
al.,
1980.
and RIVIERE,
1978.)
and confirm the potential
protein source represented by tree forages during the dry
season when grass carpet CP content is bellow 5 pi00 and the
CP ratio of dried grasses on browses is close to zero.
A.
raddiana pods and leaves A. albida and C. procera
leaves are specially high in CP (> 15 pi00 in average).
Leguminous pods are not sensitive to phenological stage in
term of CP content. That is in agreement with our first
results (FALL, 1991). It was not the case for their leaves
which CP level was negatively influenced by age.
CP content in Calotropis and Adansonia varied within a
wide range. Those variations cannot be explained only by age
effects. Variety pressure needs to be checked. Guiera leaves
had the lowest CP content in a11 season of sampling.
Fiber content (NDF) were quite variable. The lowest level
were recordered in Calotropis (27%) while the highest one were
observed in Guiera leaves (72%).
-
Minera1 content of tree forages (see table 2) shows a
globally low phosphorus content. Most of samples were bellow
the critical level of 0.3 ~100 and the Ca/P ratio were often
8
bad exept for A. raddiana pods. SO browses cannot supply P
which is the most serious minera1 deficiency in the Sahel.
Copper and Zinc are among the main minera1 umbalance in the
Sahel. Browses bring only the minimum required (INRA, 1989): 4
to 7 ppm and 15 to 35 ppm respectively for copper and Zinc. SO
a
minera1
mixture is
advisable
for
minera1
deficiencies
prevention in the Sahel.
DIGESTIBILITY OF TREE FORAGES
RATION DIGESTIBILITY: (Table 3)
The digestibility of rations involving A. raddiana pods
and A.
digitata leaves were the highest one
(56 ~100 in
average),
followed by
ration
with
different
level of
Calotropis procera (50 pi00 in average). Rations with Guiera
leaves were the less digestible and that specie seemed to have
a negative
effect
in the digestive tract. The higher was
Guiera level in the ration the lower the digestibility. The ad
libitum level caused mortality of 3 over on 6 sheeps. The
tria1 was stopped after one week of adjustement.
The ration involving A. albida leaves was of low digestibility
while the one with the pods was intermediate.
OM and CP digestibility had the same variation profile.
DIPPERENCIAL DIGESTIBILITY OF BROWSES:
Browse
digestibility
are
presented in
table 4.
Although
variations between trials were high, the same hierachy was
recpected. Mimosacea pods were the most digested followed by
Adansonia digitata and Calotropis procera leaves. Guiera and
A. albida old leaves were of the lowest digestibility.
Variation between trials cari be explained in part by plant
age. Guiera leaves of june were more digested than that of
March. Another variation factor involves ration composition.
High level of Guiera does not seem to be accepted by sheep. It
cari be explained by a high level of tannins which fluctua-tes
from 4 to 11 ~100 DM (Kessler and Breman in_preparation; IEMVT
unpublished data).
In Calotropis leaves the between tria1 variations cannot be
explained by the plant age in the current stage of our
9
results. More investigations are needed to clarify the variety
effect.
Finally the role of browse level could be a variation source.
In the example of Adansonia leaves the same sample
DM and OM
digestibility varied within 20 points between 37 and 49 ~100
of the ration. In case of a non toxic specie a hundred ~100
browse diet is applicable to record information on intake and
palatability.
Current trials in LNERV give priority to the
highest browse levels (50 to 100 ~100).
SO observed variations in the in vivo tria1 results,
athought corresponding to litterature indications (see KESSLER
and BREMAN review in preparation), suggest more precautions in
sampling methods. One has to give large informations about
variety sampling date and site to comment on the results.
IN SACCO DEGRADATION OF TREE FORAGES:
(table 5 and 6;
figure 1 and 2).
Legume pods had stable and good degradation profile. More
of 70~100 of DM disappeared at 48 incubation time. A. albida
leaves are variable and sensitive to age. Young leaves were
highly degraded while old one were of poor intra-rumenal
degradation (Fall, 1991). A. raddiana leaves and pods had a
comparable
and
good
degradation
profile.
Adansonia
and
Calotropis
leaves are the most degraded sample (Deg 48h >
80~100) while guiera leaves were of poor degradation (Deg 48h
< 40 plO0).
Legume pods as well as Adansonia and Calotropis leaves of
high rumen degradation are potential N source for ruminants.
Browse
degradation profile is
influenced by chemical
composition.
Ce11
wall
components
play a
negative
role
(Bammualin et al.,
1980
reported by
Nitis,
1992.).
Particularly N location into ce11 wall (Krishnamoorthy et al.,
1982; Sanderson and Wedin 1989.). The major part of digestible
N is located in ce11 solubles. ADFN is not important (less
than 20~100 of total N) in tropical browses but it plays a
significant (PcO.05) role in N degradability (Fall and Doreau
1993, in press). Our results confirm that as Guiera leaves, of
highest ADF content, were the less degradable. Also the role
10
of tannins is emphasized (Mc Leod, 1974.; Diagayete, 1981.;
Reed et al.,
1990.
and Leinmuller et al.,
1991.).
Plant
tannins
depress
browse
digestibility.
Differences i n
litterature reports cari be explained in that the reaction
tannins-proteins
is governed
by multiple
factors such as
tannin type, and level in feeds. Hydrolysable tannins cari be
modified by digestive enzymes and thus, do not depress CP
digestion
while
condensed
one
precipitate
with
proteins
forming
indigestible
complexes.
Their
effect in
protein
balance is negative.
Tanins level less 3 pi00 (NITIS, 1992.)can give benefit in
good quality proteins digestion by protecting them, for direct
absorption in the small intestine. Above that level occurs a
phenomenon of precipitation which makes them indigestible.
Tanin analysis are in progress in IEMVT for checking of their
effect upon degradation.
INFLUENCE OF TREE FORAGES ON GROWING SHEEP PERFORMANCES:
Five
trials
were
carried
out to
study
secondary
productivity of A, albida pods, G, senegalensis, C. procera
and A. digitata leaves.
In tria1 5 (see table 7) G. senegalensis leaves were
compared to A. albida pods. The average daily intake was close
between the two groups and superior to the control one. A.
albida
pods
group was
significantly
(PeO.05) higher in
liveweight gain compared to Guiera one and the two groups were
significantly
different compared
to the unsupplemented one
which was at maintenance level. Guiera group were slightly
higher in performance while A. albida pods ration allowed a
semi-intensive growing.
It cari be compared to Glyricidia
sepium
which
allowed
a daily liveweight change
(LWC) of
4Og/day (Smith and Van Houter, 1987.) and Albizia zygia, 800g
/ day giving a LWC of 48g a day (Bouche1 et al., 1992.) while
Konig et al. (1992) reportered a negative effect for Atriplex
nummularia leaves at the level of 25 to 75 ~100 of the diet in
sheep performances wihch have lost 31 to 93g a day.
11
Guiera was compared to C. procera leaves in tria1 7 (see
table 8). Calotropis group was superior in intake and animal
performances.
Animal performances were higher for Guiera in tria1 5
compared to tria1 7. That result has been suprising as Guiera
intake were superior in the last trial. It cari be explained by
the different nature of the basa1 diet made of early dry
season bush hay of better quality compared to rice straw. A
higher total DM intake
(89 vs
64 g/Kg P"=75)
was
also
recordered.
C. procera at the level of 1.5 pi00 allowed semi-intensive
growing of Young sheep. Sundrying seems to alleviate eventual
toxicity of that tree forage wihch is well consumed without
any sign of toxicity.
Objectives of tria1 3a, 3b and 8 (see tables 9, 10, and 11
respectively)
were to
study
the
influence of
Adansonia
digitata leaves on Young sheep performances.
We had many
health problems in tria1 3a; that's why a repetition was done
in tria1 3b. Animal performances were 16 and 27g per day
respectively for the level 100 and 200g per day. They were
significantly superior (PKO.05) compared to the control group
which was loosing 56g/day. The 300g level, expected to be
higher, was close to the 200g one in term of liveweight change
(21 vs 27g /day). The tria1 duration
(70 days) might be a
fimiting
factor
for
maximum
performance
record as
the
liveweight curve was in ascending phase when it stopped. Those
values are close to that of Alchomea cordifolia (48 ~100 of
the diet) wich gave an average LWC of 25g (Kouonmenioc et al.,
1992.)
CONCLUSION:
.Browses represents the only CP source available during the
dry season for ruminants in pasture based systems of the dry
tropics.
Although their nutrient content cari be high, the
digestive utilisation may vary according to species, age, and
plant part. A. albida and A. raddiana pods at the level of 15
to 25 pi00 cari achieve semi intensive fattening ( 16 to 30 g /
day) in sheeps while C. procera and A. digitata leaves of
12
higher nutrient content cari be given to sheep up to 30 ~100
level in the diet,
in intensive fattening program.
Current
trials involve evaluation of intake and liveweight change of
ration with higher proportion of tree forage for toxicity
screening.
BIBLIOGRAPHY
AOAC,
1975.
Officia1
methods of
analysis.
12th ed.
A.O.A.C., Washinaton, DC: 152-169.
BOUCHEL D., BODJI, N.C. et KOUAO, B.J. 1992. Effet de la
complémentation d'une ration de base de qualité médiocre par
Albizia zygia sur le comportement alimentaire et la croissance
d'ovins Djallonké. In: The complementaritv of feed resources
for animal production in Africa. Stares J.E.S., Said A.N. and
Katesile J. ILCA Addis Abeba. pp 113-125.
DHANOA, W. S., 1988. Research note on the analysis of
dacron bag data for low degradability feeds. Grass and Foraae
Sci., 43: 441-444.
DIAGAYETE M., 1981. Untersuchungen zur erweiterung der
kenntnisse
über
den
futterwert
wastafrik a
nisher
futterpflangen.
Dissertation zur erlarauna des srades eines
doktor der aararwissenschaften, Universitat Hohenheim: 135~.
FALL, S-T.,
1991. Digestibilité in vitro et dégradabilité
in
sacco
de ligneux fourragers disponibles
sur pâturages
naturels au Sénégal. Premiers résultats. Rev. Elev. Med. Vet.
Pays Trop. 38 (3): 345-354.
FALL, S-T.
and MICHALET-DOREAU,
B.
1993.
Comparative
rumina1
nitrogen
degradability of
tropical
browse
and
temperate forages. Proceedinas of the XVII th International
Grassland Conqress. Australia New Zealand. February 1993, In
Press.
GOERING, H-K,
and VAN SOEST, P.J.,
1970.
Forage fiber
analysis
(Apparatus,
Reagents,
Procedures
and
some
applications) Aariculture Handbook 379 US Dot of Aariculture.
2op.
-
GUERIN, H., 1987. Alimentation des ruminants domestiques
sur pâturages naturels sahéliens et sahélo-soudaniens: Etude
methodologique dans la region du Ferlo au Sénégal. These de
Doctorat ENSA Montnellier 211~.
13
IN=, 1989. Ruminant nutrition: Recommended allowance and
Feed tables. Jarriqe R. ed. INRA France.
REARL, L-C., 1982. Nu-trient requirement of ruminants in
developping countries.
International Feed Institute, Oreaon,
UT, USA, 381 p.
KONE, A-R.,
1987. Valeur nutritive des ligneux fourragers
des
régions
sahéliennes
d'Afrique
Occidentales.
Recherche
d'une méthode simple d'estimation de la digestibilite et de la
valeur azotée. Thèse de Doctorat 3ème cvcle.' Univ. Paris VI.
131 p.
KONIG, R.C.W., BECKET, K., BENJAMIN, R.W. and SOLLER, H.
1992. Performance of sheep and goats with offspring on semi-
arid saltbush (Atriplex nummularia) - grassland ranges in the
early dry season. In: The comnlementaritv of feed resources
for animal nroduction in Africa. Stares J.E.S.. Said A.N. and
Kateaile J.A. editors. ILCA Addis Ababa Ethiopia. pp 63-74.
KOUONMENIOC, J., LACOSTE, A. et GUERIN, H, 1992. Etude de
l'influence de
quatre
fourrages
ligneux
sur
l'evolution
pondérale des ovins de la race naine de l'Afrique de l'Ouest.
In:
The
comnlementaritv
of
feed
resources
for
animal
production in Africa. Stares J.E.S., Said A.N. and Kateaile
J.editors. ILCA Addis Ababa. Ethiopia. pp 97-110.
KRISHNAEIOORTHY,
U.,
MUSCATO, T-V.,
SNIPPEN, C-J., VAN
SOEST, P.J. 1982. Nitrogen fractions in selected feedstuffs.
Journal of Dairv Science 65: 217-225.
LANPREY, H-F.,
HKRLOCKER, D. J., PIELD, C.R. 1980. Report
on the satage of knowledge of browse in West Africa. In: Le
Houerou ed. Browse in Africa: The current stase of knowledqe.
Addis Abeba. ILCA, 1980. pp 33-54.
LECHNER-DOLL, H., RUTAWENGA, T., SCHWARTZ, H-J., SCHULTKA,
W. and ENGKLHART, V. W. 1990.
Seasonal changes of ingesta
mean retention time and forestomach fluid volume in indigenous
camel,
cattle, sheep and goats grazing a thornbush Savannah
pasture in Kenya. J. of Aaric. Sci. Camb., 115: 409-420.
LE HOUEROU, H.N. 1980. The role of browse in the sahelian
and sudanian zones. In: H.N.
Le Houerou editor. Browse in
Africa: The
current
staqe o f
knowledae.
International
Livestock Center for Africa. pp 83-100.
LEINMJLLW, E., STEINGASS, H., MENEE, K-H., 1991. Tannins
in ruminant feedstuffs. Anim Res and Develon., 33: 9-62.
HC LEOD, H-N-, 1974. Plant tannins- Their &le in forage
quality.Nutr. Abstr. and Rev., 44: 803-815.
WICHALET-DOREAU,
B. and OULD-BAH, W-Y., 1989., Estimation
of the extend of bacterial contamination in bag residues and
it's influence on in sacco measurements of forage nitrogen
14
degradation in
the
rumen. In:
Proceedinqs of
the XVI
International Grassland Concrress: 909-910.
MICHALET-DOREAU, B., VERITE, R. et CHAPOUTOT, P., 1987.
Méthodologie de mesure de la dégradabilité in sacco de l'azote
des aliments dans le rumen. Bull. Tech. CRZV Theix, INRA
France. 69: 5-7.
NITIS, 1. M., 1992. Fodder shubs and trees in small holder
farming
systems in
the
tropics. In:
Natural
Resources
Develonment and Utilization. R. De Jona, T. Nolan and J. Van
Bruchem editors. EEC. IAC. Wageningen. The Netherland. pp 36-
51,
ORSKOV, E. R., DEB HOWELL, F. D. and MOULD, F., 1980. The
use of nylon bag technique for the evaluation of feedstuffs.
Trop. Anim. Prod., 5: 195-213.
REED, J.D., SOLLER, H. and WOODWARD, A., 1990. Fodder tree
and straw diet for sheep: intake, growth, digestibility and
the effect of phenolics on nitrogen utilisation. Anim. Feed
Sci. and Technol., 30: 39-50.
RIVIERE, R.
1978.
Manuel d'alimentation des ruminants
domestiques en milieu tropical. IEMVT Maisons-Alfort Ministère
De La Coonération France.
SANDEXSON, 54. A., WEDIN, W-F.,
1989:
Nitrogen in the
detergent fibre fractions of temperate legumes and grasses.
Grass and Foraae Science 44: 159-168.
SS,
1985. SAS user's guide: Statistics. Cary, NC: SAS
Institute Inc.
SMITH, O-B,
et VAN HOUTERT,
M.F.J.,
1987.
La valeur
fourragere de Glyricidia sepium. Revue Mondiale de Zootechnie.
62: 57-68.
VON MAYDELL, H-J.,
1983.
Arbres et arbustes du Sahel.
Leurs
caractéristiques et
leur
utilisation.
Publie nar
l'office
Allemand de la Coopération Technioue (GTZ) 2eme
édition 531~.
ACKNOWLEUGEMENTS:
The authors are indebted to Massamba Diop and Bernard
Ahokpe
for their technical support in feeding trial, to
Bassirou Diaw for assistance in nylon bag studies and to M.
Dione for the supply in plant material. --
This work has been jointly funded by IFS (Grant No B/1107-
02) and EEC (ST2.A.75-IRL).
TABLE 1
CHEMICAL COMPOSITION OF TREE FORAGES
Maan Value g/ Kg DM
@ange)
SPECIES
PLANT-PART
NO
MS
MM
CP
NDF
ADÇ
Li
4cocia albida
Pods
5
920
44
113
385
221
(960-894)
(38-50:
[104-122)
(388-390)
(120-275)
Leaves
4
918
99
152
396
296
(896-955)
(88-1091
1128-194)
(315-476)
(191-401)
kocia roddiana
Pods
7
913
61
176
471
341
144
(896-961)
(49-7 1:
1737-205) (418-523)
(375-407)
(139-148)
Leaves
17
913
121
182
371
285
190
(864-959)
(98-180)
'125-220) (346-363)
:229-334)
(181-216)
hiera senegalensis
Leaves
30
915
75
109
615
517
98
/
c883-958)
(48-151)
(70-122) (574-728)
1487-615)
(61-150)
rdansonia digitata
Leaves
9
896
110
102
487
272
116
1872-928)
(56-l 39)
(52-138) (521-452)
1157-360)
(61-171)
alotropis procera
Leaves
19
882
200
159
290
217
116
1854-908)
(68-242)
(242-68) (276-302)
199-241)
(81-109)
(379-151)
(68-242)
Table 2:
CHEhiîCAL COMPOSITION OF TREE FORAGES
Mean value
(range)
‘owse species
Ca
P
CU
Zn
N a
K
g/Kg DM
g/KgDM
ppm
ppm
ppm
ppm
cacia albida pods
3.39
1.63
4.5
19.1
953
1.4
(2.4-4.4)
(1.47-1.91)
cacia albida leaves
17.51
1.66
7.3
29.3
832
1.1
(14.9-24.11)
(1.33-2.01)
(6.7-7.9)
(27.5-31.2)
(486-1178)
(0.9-1.3)
mcia raddiana pods
8.12
3.35
3.4
38.5
4 1
1.6
(1.83-8.12)
(1.82-8.74)
(2.7-4)
(29.7-50.9)
(15-64)
(1.2-1.8)
cocia raddiana
laves
22.3
1.67
3.7
29
448
1.2
(15.3-31.7)
(1.0-2.8)
(2.2-6.7)
(22.7-41.9)
(116-947)
(0.6-1.5)
lera senegalensis
q ves
15.2
1.4
1 0
29
315
0.7
/
(8.2-21.2)
(0.5-1.8)
(5.0-19.7)
(13.7-64.3)
(96-52 1)
(0.3-1.1)
dansonio digitoto
aves
24.9
2.29
8.6
27.6
769
96
(5.3-39.6)
(1.0-6.10)
(7.5-10.5)
(25.9-3 1 .O)
(449-1352)
(84-65)
alotropis procera
‘aves
26.13
2.2
6.7
36.4
8771
3.5
(13.8-49.4)
(O-6-3.9)
(4.0-8.0)
(19.6-54.3)
(5833-12213)
(2.0-6.9)
TABLE 3:
W VIVO WGESTIBILITY O F DtETS P. 100
FD
IDIET CDU’0NENT P. 100
E T DIGES .ITY P.100
1
IGESTIBILITY NO
BROWSES ’
GRCUNDNUT
IICE
IUSH
DM
OM
CP
I
CAKE
;TRAM
IAy
4 9 8
A c a c i a obida o!d Ieoves
5 0
1c
4c
4o.c
4 2 . 9
26.4
4 9 9
Acacia atbida nature fruits
27
ll.
60
53.4
57.3
69.8
16
Acacia raddiana nature fruits
52
11
37
5 7 . 1
58.6
6 6 . 1
17
Acacia raddiana nature fruits
50
1c
40
55.5
57.3
6 1 . 4
500
Guiera serwgatansis baves
33
16
5 1
43.9
47.8
52.1
4
II
a
a
8 4
6
8
a
a 4
4 9 . 1
4 7 . 7
5 8 . 7
5
16
8
76
7
15
a
77
47.1
42.7
53.0
23
15
10
75
5 2 . 7
5 5 . 4
5 1 . 4
1 8
42
1 2
48
4 3 . 4
46.0
43.3
1 9
II
1 0 0
10.3
10.8
- 7 0 . 0
2 0
II
75
25
3 5 . 7
35.7
2 5 . 4
3
:alotropis procera lsaves
9
9
a2
50.9
l2
t,
11
1 0
7 8
50.6
9
PI
1 2
1 2
76
4 8 . 7
50.5
65.8
22
8,
1 6
11
73
5 1 . 4
53.5
67.1
1
0,
17
8
75
5 5 . 9
1 0
II
20
12
69
4 9 . 2
50.2
59.2
26
Adamonia dtgitata Iaaves
37
1 9
44
62.7
66.1
67.1
2 7
Adansonia digttata Iaaves
49
1 0
4 1
5 2 . 3
58.3
6 6 . 8
TABLE 4:
BROWSE DIGESTIBILITY (DFFERENCIAL
METH~D OF CALCULATION)
DIET COMPONENT P.100
BF
FIOWSE DIGESTIBLITY P.' 1
D IGESTIBILITY
1 BROWSES
Gf<OUNDNUT -7 CE
BI USH
DM
OM
CP
t NO
DATE
CAKE
S TRAW JAY
498
Al cocia albida old Ieavas
50
1 0
40
28.0
31.2
14‘0
499
A cacia albida nature fruits
27
13
60
65.9
70.7
100.0
77.3
1 6
sacia
A.
raddiano nature fruits 48
11
37
62.1
64.0
1 7
A l :acia raddiana nature fruits 50
10
40
61.2
63.2
69.2
500
Gl riera senegalensis
leaves
33
16
5 1
24.8
30.6
4 ,ARCH 88
II
8
8
84
59.0
46.0
37.7
6
MARCH 88
8
8
84
5
MARCH 88
16
8
76
40.6
18.6
33.0
7
MARCH 88
II
15
8
77
23
APRL 88
t,
15
10
75
70.6
68.0
1
1 8
4PRL 88
42
12
48
33.3
40.7
29.3
1 9
APRIL 88
,t
100
10.3
10.8
-70.0
20 APRIL 88
75
25
17.4
18.0
16.6
3 APRIL 88
C alotropis procera leaves
9
9
82
II
2
APRIL 88
11
10
78
,t
9 DECEM 88
12
12
76
35.5
39.1
70.6
II
22 JUNE 88
16
11
73
59.8
52.5
67.6
1
JUNE 88
17
8
75
1 0 DECEM 88
20
12
69
50.5
57.5
61.5
26 SEPT 88
A dansonia digitata Ieaves
37
19
44
70.5
71.0
100.0
27 SEPT 88
b idansonia digitata Ieaves
49
10
41
51.4
57.1
96.3
-
TABLE 5
IN SITU DM DEGRADATION OF TREE FORAGES
r
INCUBATION TIME ft10u r s )
-
NO
l-
TREE FORAGES
DIG
2
4
8
24
48
72
96
Calotropis procera feuilles
5
43.2
45.6
55.7
80.8
92.9
93.3
93.6
Adonsonia digitata feuilles
1
29.3
29.7
30.9
52.8
78.4
83.0
82.8
Acacia raddiana feuilles
3
34.7
35.1
36.7
50.6
66.9
72.4
73.3
Acacia raddiana feuilles
2
34.0
34.9
39.9
58.3
69.3
74.2
75.3
4cacia albida feuilles
2
59.0
65.0
69.0
kacia albida fruits
1
71.0
74.0
76.0
Liera senegalensis feuilles
a
31.4
31.3
34.8
39.6
41.2
44.3
* FALL
1991
TABLE 6
NITROGEN DEGRADATION IN TREE FORAGES
P 1 0 0
r
II\\ICUBATIC
-
rs>
‘REE FORAGES
2
4
8
2 4
4 8
7 2
9 6
9 7 . 5
Zalotropis procera leaves
6 1 . 7
6 3 . 2
7 3 . 0
8 9 . 6
96.6
9 7 . 2
8 5 . 6
ddansonia digitata leaves
21.1
2 5 . 0
26.1
4 4 . 6
8 0 . 5
8 5 . 9
J
7 8 . 7
4cacia raddiana leaves
2 1 . 6
2 1 . 3
2 1 . 7
3 9 . 9
6 7 . 5
7 6 . 3
9 0 . 8
Acacia raddiana pods
5 6 . 5
5 6 . 8
6 0 . 9
7 7 . 2
8 6 . 0
9 0 . 0
Acacia albida leaves
5 6 . 0
6 2 . 0
6 8 . 0
7 5 . 0
Acacia albida pods
6 0 . 0
6 9 . 0
7 1 . 0
7 2 . 0
3 7 . 9
Guiera senegalensis leaves
1 8 . 4
2 2 . 2
2 3 . 0
2 3 . 4
2 8 . 3
3 3 . 3
TABLE 7: Influence of Acacia albida pods and Guiera senegalensis
leaves on growing sheep performances
SHEEP LOTS
I
II
Ill
:ontrol)
ANIMAL DIETS: (Kg)
ad
ad
Rice straw:
F
libitum
libitum
Peonut cake:
C l
0.1
0 . 1 2 5
Acacia albida pods:
C2
DRY MATTER INTAKE:
l adlibitum0.10.2 -
Guiera senegalensis leaves:
C2
0 . 2
F
3 6 9
3 4 2
4 1 3
g/head/day
Cl
9 0
9 1
1 1 8
c 2
1 7 4
1 6 6
TOTAL: (g)
6 3 3
5 9 9
5 3 1
TOTAL: g/KgPO .7 5
6 3
6 4
5 4
LIVEWEIGHT:
Starting: (Kg)
20.1
18.9
2 1 . 4
End: (Kg)
23.1
2 0 . 8
2 1 . 0
Average: (Kg)
2 1 . 6
1 9 . 8
2 1 . 2
Total liveweight gain: (Kg)
3.0
1.9
- 0 . 4
Daily liveweight gain: (g)
4 0 . 0
2 5 . 0
- 5 . 0
TABLE 8: Influence of Calotropis procera and Guiera senegalensis
leaves on growing sheep perfomances
SHEEP LOTS
A
B
C
control
4NIMAL DIETS: (Kg)
ad
ad
ad
3ush hay:
F
libitum
libitum
libitum
‘eanut cake:
Cl
1 0 0
1 0 0
1 0 0
Zalotropis procera leaves:
c 2
-
1 5 0
Juiera senegalensis leaves:
1 5 0
-
IRY MATTER INTAKE:
F
7 1 6
8 2 4
7 4 3
g/head/day
Cl
8 9
9 8
9 4
c 2
1 0 5
1 2 6
TOTAL: (g)
9 1 0
1 0 4 8
8 3 6
TOTAL: g/Kg P0.75
8 4
9 3
8 0
LIVEWEIGHT:
Starting: {Kg)
2 2 . 0
2 2 . 6
2 1.6
End: (Kg)
2 5 . 7
2 7 . 9
2 3 . 9
Average: (Kg)
2 3 . 8
2 5 . 2
2 2 . 7
Total liveweight gain: (Kg)
3.7
5 . 2
2 . 3
Daily liveweight gain: (g)
4 0 . 0
5 9 . 0
2 5 . 0
TABLE 9: Influence of Adansonia digitata leaves
on growing sheep performances (tri:al No sa)
SHEEP LOTS
II
Control
ANIMAL DIETS: (g)
Rice straw:
F
rd libitum
ad libitum
Peanut cake:
Cl
7 5
1 5 0
Adansonia digitata leaves:
c2
2 0 0
0
DRY MATTER INTAKE:
F
4 5 0
5 1 4
g/head/day
Cl
1 0 6
1 5 7
c 2
191
0
TOTAL: (g)
7 4 7
6 7 1
TOTAL: g/KgPO .7 5
6 9
71
LIVEWEIGHT:
Starting: (Kg)
2 2 . 0
19.8
End: (Kg)
2 5 . 7
2 0 . 0
Average: (Kg)
2 3 . 8
19.9
Total liveweight gain: (Kg)
3 . 7
0.2
Daily liveweight gain: (g)
4 0 . 0
1 .o
TABLE 10: Influence of Adansonia digitata on growing sheep
performances
(triai n03b)
;HEEP LOTS
I
II
III
contra1
4NIMAL DIETS: (g/head/day)
ad
ad
ad
iice straw: F
F
libitum
libitum
libitum
‘eanut cake:
Cl
1 0 0
1 0 0
1 0 0
Adansonia digi tat a leaves:
c 2
1 0 0
2 0 0
0
DRY MATTER INTAKE:
C
3 9 4
4 2 6
4 1 6
g/head/day
Cl
91
9 2
9 3
C2
8 7
1 7 6
0
TOTAL: (g)
5 7 2
6 9 4
5 0 9
TOTAL: g/Kg P0.75
56.1
6 6 . 7
5 5 . 7
LIVEWEIGHT:
Starting: (Kg)
2 1 . 7
2 2 . 0
2 0 . 5
End: (Kg)
2 2 . 6
2 3 . 5
17.7
Average: (Kg)
22.1
2 2 . 7
19.1
Total liveweight gain: (Kg)
0.9
1.5
- 2 . 8
Daily liveweight gain: (g)
16.4
2 7 . 3
- 5 6 . 0
Tlhl
l -
.
4.
,.-Il
.._._ -_
-1
I
J-----!-
-II-?,-,-
-._
IABLL I I :
inriuence 01 ,4oonson1u
uigirara o n
growing sheep performances (tria1 No 8)
SHEEP LOTS
Il
ANIMAL DIETS: (g/head/day)
Rice straw:
F
ad libitum
Peanut cake:
Cl
1 5 0
Adansonia digitata leaves:
c 2
3 0 0
DRY MATTER INTAKE:
F
3 0 9
g/head/day
Cl
1 2 4
c 2
2 7 3
TOTAL: (g)
7 0 6
TOTAL: g/Kg P0.7 5
7 5
LIVEWEIGHT:
Starting: (Kg)
1 8 . 4
End: (Kg)
19.9
Average: (Kg)
2 2 . 5
Total liveweight gain: (Kg)
1.5
Daily liveweight gain: (g)
21 .o
Figure 3 - in situ degradation of Browses
DM degradation ~100
?2#
80
---._---.-_-.-_- _____
..---- ----_-~--_--._
t
t
t
I
I
l
t
2
4
8
24
48
72
96
h3Jbation time (t-l)
- C.prOcera lea
+ A
.
digitAta ” +- A.raddieim ” -0- A.risiddi8nis po
--Y& Aalbida leav -$- A . albida p o d * G . senegalens
FïQure 4 -
N degradation in browses
in situ dsgradation plO0
120
0:’
1
1
t
t
2 4
a
24
48 .
72
96
lrcutxtion time (h)
-- c.proccr A 1
--I- A.dlQitOi~ L
;ti- A.rBddiarm L ++- A.reddifmEJ P
-x- A.albid3 L
il- Aalbid3 P
--A-- G.sensgalonJi