8.. REPUBLIQUE DU SENEGAL MINISTERE DU...
8..
REPUBLIQUE DU SENEGAL
MINISTERE DU DEVELOPPEMENT RURAL
iBil INSTITUT SENEGALAIS
DE
RECHERCHES AGRICOLES
Communication presented at the PANESA/ARNAB workshop
Malawi - December 5-9 th 1988
by Safiétou Touré FALL
Direction des Recherches
sur la Santé et les Productions Animales
IMPROVEMENT OF NITROGEN LEVEL IN RUMINANT?S DIET
The problem of dissemination of research results on
utilization of urea and browses as nitrogen sources in
sahelian feeding systems.
Contribution presented at the PANESA/ARNAB workshop
Malawi. December 5-9 1988
BY
Dr Safietou Fall
ISRA LNERV
BP 2057 Dakar
Senegal
1
t
INTRODUCTION
Bioclimatic contraints are still the main limiting
factor to food availability for ruminants in the sahel.
The dissemination of available research results wich
propose well adapted solutions to those difficulties is of
particular urgency.
Cereals as well as high energy and nitrogen concentrates
remain costly with additionna1 problems of transport and
livestock is in competition with others alternative usages.
Some high nutritive value agro-industrial by products are
exported;thus their availability is poor.
SO in sahelian countries ruminant feeding systems are
naturally based on natural pastures and low quality roughages
like cereal straws witch are good sources of cellulose but
low in digestible nitrogencsee table Z).Chemical and/or
physical treatment including nitrogen,energy and minera1
supplementation are indispensable for optimal utilisation of
low quality roughages.
Among nutritionnal constraintsprotein deficiency
appears to be one of the most important.Protein sources are
expensive and some proposed solutions involving utilisation
of oil meals and cereal brans seem to be of poor apliability
at the great scale of extensive livestock.For that purpose
urea and browse plants could be of a good help as locally
available and cheaper nitrogen sources.
Over more than 50 past yearsresearch works on protein
2
-
_.._
..-
---
.--.----
--
_--- _.-.-
-- --
-..
~..___
.. ,.-...
“-_ ._
c
ruminant nutrition have identified urea as the most promising
chemical for cereal straw quality improvement and non protein
nitrogen supplementation(Jackson 1979 > Sunstol 1984).However
research results have been of poor dissemination in African
traditionnal livestock.
Rrowse plants are other source of protein readily
available in pastures.During the dry season they cari reach 50
per cent of the cattle diet while they represent the basis of
small ruminants nutrition(around 80 per cent of their diet)
(Guerin et a1 1985),in grazing conditions.Available
informations describe the nutritive value of trees and
shrubs;their high protein content and aptitude to enhance
nitrogen level of ruminants diet is emphasized (Rivière
1978,in Le Houerou 1980,Kone 1984,Kone 1987,Fall 1988)
SO urea and browses give
good possibility to limit
nitrogen deficiencies in Sahel and improve livestock
productivity.
Our objectives is to highlight several considerations
linked with practical dissemination of research results,to
identify constraints and propose some solutions able to make
easy nitrogen supplementation of low quality fodder using
urea and browses at thé: farmer level and find out some on
farm-research areas in relation with urea and browses usage
witch need to be investigated in priority.
3
‘
1. Constraints to urea on farm utilisation in aahslian
countries
1.1. Urea for nitrogen supplementation of ruminants diet
1.1.1. Urea availability (Sec table 1)
In most of the sahelian countries urea is not locally
produced.This chemical is imported and widely used as
fertilizer.In Senegal around 10,OCJO tons per year are
imported and manufactured for fertilizer production.This
quantity is bellow the national requirement for soi1
improvement and urea usage in livestock feeding could
increase the deficit.
Governement contribution to urea cost is decreasing from
a year to another.The ob3ective is to suppress this
contribution for priva-te initiative resulting in a decrease
in urea distribution.
SO availability and cost of urea is a major constraint
to it's popularization.More quantity is required for both
livestock an soi1 produtivity improvement.
The question is weather urea supplementation is
feasible and profitable in the conditions of extensive
livestock or not.On-farm trials and economics could help to
prove it.
4
1.1,2.2 Caracteristics of urea added diets.
To optimize urea digestive usage a good supply of energy,
true proteins and minerais is needed.
- Easily digestible source of energy is needed.Molasses
and cereals are good supports of urea.The first is available
in areas of sugar cane prodution while the second suffers for
monogastric (including human) nutrition competition.
-Urea mixture in the diet has tu be the most homogenous
possible tu ensure a progressive consumption by the ruminant.
This aspect involving the diet preparation EJay be
constrainting for farmer Since urea iS sold in Pearl form.It
has to be solubilized in water before to be mixed with the
other coIrJporJentE of the diet.This imply a good water supply
but also a blendor or a hand mixer like fork to impregnate
forage with urea solution.
-In addition to urea supplement,true proteins are
required for a well balanced rations .According to NE?C (1976)
estimates urea level should not be above 30 to 40 per cent of
the protein requirement of the animal.So urea cannot solve
the whole problem of nitrsgen requirement in protein
deficient diets.
-Minerais specially calcium and phosphorus(in a well
balance)including sulphur and cobalt are required for optimal
activity of rumen microbes the true users of urea.
It puts the problem of availability of minera1 supplements
6
.
in acceptable price in rural area.A practical solution has
not been reached yet at the large scale of traditionnal
livestock.
-The water availability in the sahel is the most
important constraint to urea utilisation.The watering of urea
given animals should be as regular as possible and it is
advisable to give water at libitum.This is almost impossible
in the sahelian traditionnal system.
Temporary water points dry in the early dry season.
Drillings have a hard problem of maintenance;they do not work
often and the distance between them in ferlo area is too
high(See figure 2 Gaston et a1 1987) So herds use to be
watered once every two days.In this system water supply does
not satisfy ruminants requirements;those conditions do net
seem to allow urea introduction.
Beef fattening workshops around agglomeration where water
supply is correct offer best conditions to spread research
results involving urea usage in ruminants diet.
-Yoor palatability of urea added diets may be a
constraint to it's acceptance by ruminants.Molasses and/or
salts are excellent supports for improvement of urea added
diets palatability
Caracteristics of urea based diets summarizes some rules
to be respected in order to ensure a good absorption and
prevent ammonia intoxication.Farmers need to be aware of
them.
7
1.2. Improving nutritive value of lew guality rsughergss by
urea processing
1.2.1. Urea versus other chemical or physical methods of
straws quality improvement.
A major limiting factor to straws utilisation is their
bulkiness and low concentration in digestible nutrient.Their
nitrogen poverty specially has a negative effect upon their
digestibility.
Several methods have been used to improve intake and
digestibility of straws.
Physical treatment by chopping or milling has the
drawback that they may be costly in energy and need some
equipment.Rice straw is less rough and does no-t need to be
chopped on farm.Hand cutting with a chopper is suitable for
sorghum and milled straw to make them easily edible.
For chemical treatment of low quality roughages,several
alcaline or acid reagents are proposed.Among them the
ammoniation by urea offers greater promise in the viewpoint
of feasibility,with an added advantage that it supplies non
protein nitrogen(Jackson 1979,Sundstol 1984,Fall et a1 19871,
and that it is more accessible a-t the farmer level compared
to other chemicals.Urea is three times cheaper than sodium
hydroxide wich is not available in rural zones in Senegal for
8
example.However his usage is not without any constraint.
1.2.2. Technical constraints to dissemination of urea
treatment of cereal straws
In addition to urea availability and potential toxicity
of ammonia as described previously,there is a need tu Select
an adapted technical procedure in tropical conditions.
1.2.2.1. The method of strarw trsatment
available methods (Jackson 19791 are based on the
mixture of straw and urea at the level of 5 per cent.
In the dry procedure,urea is injected in the straw using
high pressure.After injection temperature raising seems to
give best forage quality(Jackson 19791.The cost and
availability of the needed equipment makes that technology
out of reach for sahelian farmers at the large scale.
The second way involves a small quantity of water.A 5
per cent urea solution is spread over the straw at the
proportion of 1 liter of solution per kilogram of straw to
make it reasonnably humid (sec Fall et a1 1987).The urea-
straw mixture is kept in a silo and left for incubation for
two (in tropical climate)or six weeks(in cool climate).This
way seems to be advisable in drought conditions of sahel.In
addition it prevents from risk of environment pollution.
IJrea ensiling leads to improvement of intake
9
digestibility and nitrogen content of poor quality roughages
(see table 3).However it should represent .a restricted
proportion of the ruminant diet to avoid risks of ammonia
5
toxicity for beef cattle or transmission of toxic compounds
in milk for dairy cattle(Perdock and Leng 1987,Preston and
leng 1987).In north Europe treated straw does is usually
above 30 per cent of the diet(Preston and leng 1987I.More
research work are needed to evaluate accurately the daily
optimal consumption of urea treated straws for sheeps and
cattles in Africa.
Urea ensiling method seems ta be of easy
application;however some adaptations to rural conditions are
needed.
1.2,2.2, Adaptation of urea enrilinreg metiled te rura%
conditions.
Availability of suitable eqlAipKJerJt in traditionnal
livestock areas is a serious constraint to popularization of
straw ammoniation by urea treatment.One should try to use
locally available tools.
-Straw physical treatment
Before urea ensiling long cereal straws have to be
chopped in order to make them easy to handle and the reagent
reach the ce11 wall.Most of the choppers are more or less
sophisticated and working with electricity witch may not be
available in rural areas.
II_“_--- -....- -
---. I .
Fe of agood help.Total isolation of t,hF-silo'ls a probTem.
--.
The chopping process may be done by hand with a hatchet.
Rice straw is less rough and does not need a reduction of
length.
-Tools of treatment.
IJrea solution cari be sprinkled by watering caris.
Instead of big containers made of metal like it is used
in North Europ,straw cari be urea ensiled in a silo hollowed
out of soi1 and covered with a lay of cernent or clay.
After urea solution-straw mixture the silo cari be
covered by a polyethylen tarpaulin wich cari be non available
in certain zones.In this case banana or palm trees leaves cari
be of a good help.Total isolation of the silo is a problem.
With local tools it may suffer for some gas ammonia escape.On
farm trials should precise the negative effect of loosing
ammonia through the silo.
-Ensiling time.
Although the treated StraW IYJay be of long COnSerVatiOn
in the technical viewpoint,ensiling time may be a constraint
for small scale farmers.They may not have capacity to treat a
great quantity of straw once,and prefer to treat the required
amount each week.Reported optimum ensiling time are from 10
days (in warm climatej to six weeks (in temperate countries).
Reseach efforts should be directed to studies about the
influence of decreasing ensiling time upon in the extend of
straw quality improvement.
1 1
-- . .._--_...
-..-
b.v
1.2.3. Cost of urea treatment of straw
As discussed previously,the cost and availability of
urea in rural areas are the ma.jor constraint to its
utilisation.
An estimate of treatment cost in the area of rice
production leads to triplicate it's price witch goes from 15
to 45 CFA per kilo.
Triais involving the study of milk or liveweigt gain cost
in the case of urea ensiled straw usage are scarce in
sahelian countries.
Economies of straw ammoniation by urea should be a major
on farm research work in order to precise the profit and
convince farmers about the reliakJili.-ky of the technic.
1.3. Conclusion,
Ability of urea to enhance nitrogen level of ruminant's
diet either as supplement or as chemical reagent for low
yuality roughages improvement has been proved for many years.
In sahelian countries dissemination of available
research results is limited by,a lack of suitable
eyuipment,the poor availability of urea in rural area,it's
high price and potential toxicity by quick ammonia intra
rumina1 release.
More on farm research could find solutions to technical
constraints and propose feaaible adaptations in rural areas.
1 2
Farmers training is one of the first problem to solve
before urea introduction in sahelian feeding systems.
II. Constraint to browse plants utilisation in ruminants diet
in the Sahel.
Recent results have shown the importance of trees and
shrubs in ruminants feeding in africa(in Le Houerou 1930).
In natural pasture they cari reach 70 to 30 per cent of sheep
and goat's diet during the dry season(Guerin et a1 1935).
Leaves,flowers and fruits of browses are well known for
their high level of nitrogen witch improves ruminant's
protein supply (in Le Houerou ed 1930,Kone 1934,Kone
1937,Fall 1933).
Consumed browses involve around 100 species(Le Houerou
1930).In the senegalese sahelian ferlo area the main genus
m-e Acacia,Balanit~~,Cal~tr~p~~~#~~~~a~~~~~~a,Zy~~~~~~
and
combretum.
Nutritive value.,harvesting and manadgement constraints
cari be a limiting factor to browse usage at the farmer level.
2.1. Nutrive value of browse plants,
2.1.1 Chemical composition.
Chemical composition of browses may be a limiting factor
13
--' ..
._-._._.
4
to their digestibility.Their high maturity explains the high
proportion of ce11 wall witch plays a negative role upon
digestibility.Part of the proteins may be imprisoned in
lignocellulose and make them unreachable by protein microbes
(Guerin et a1 1938) .So the total protein may not be
available.It depends on the degree of lignification,the age
and part of the plant.
Occurence of tannins in browses has been mentionned by
Mc Leod (1974),Diagayete (1983) and Reed et a1 (1985).Those
antiquality factors have a negative effect upon digestibility
and protein metabolisme specially.
Research efforts should try to identify the best period
of harvesting according to the stage of developpement and
part of the plant witch nutrient cari be really available.
Limiting factors tu browse intake are in relation with
chemical composition.Some species cari be rich in digestible
nutrient but not interesting in the pastoral viewpoint
because they are unpalatable.
Tannins and other toxic compounds play a negative role
on trees and shrub's palatability.Most of them remain to be
identified,their toxicity and seasonnal variations studied.
However browse intake varies according to the season and
year.In case of drought when food is scarce,ruminant are
hardless to please and accept scme bad taste species.
14
5
A long period of adaptation seems to improve browses
intake.
2.1.3. Digestibility and intra-rumina1 degradation.
A high proportion of ce11 wall and lignin fraction
contribute to lower digestibility of browses.The poor intra-
rumina1 solubility at a short time of incubation explains in
part,the low intake of some speeies (Fall 1988J.Some research
work could try to find out a feasible method of browse
ensiling to limit the negative role of ce11 wall.
2.2. On farm utilisation of trees and ahrubg,
2.2.1. Browse harvesting.
Most of the sahelian countries do not have a legislation
witch specify the way of natural pasture utilisation.This
judicial lack should be filled to allow farmer to be really
involved in range manadgement.
In addition the moving of herds looking for water and
food makes difficult a planification of pasture utilization.
SO browse are used freely in pasture.Some species are over-
grazed while others are not touched.Stocking rates are often
too high and bush fire is still destroying a great part of
pastures.
TO avoid those constraints,for a well planed utilisation
of available feed ressource farmers have to tut and save
15
-7
-
trees and shrubs for the hard period of dry season.
Technics of exploitation have been reviewed by Plot
(198O).%metime trees are entirely Cut down.That methsd do
net help regeneration and protection of environment.It should
be advisable to tut the upper leaves and alluw regeneration
of trees.
2 . 2 . 2 . Storage o f trese a n d ahrubs,
In the sahel sturage of browses as a fndder reserve is a
necessity.
Sun drying is easily applicab1e.Thi.s method is utilized
for most of the harvested Acacia fruits in west Africa.
However this procedure may have a negative effect upon
nutritive value of some species.
Ensiling with salt,used to store Alzadirachta indica
leaves(Hentgen 1985) seems to be a promising methcjd.However
training of farmers is suitable before introducing that
technology.
2.2.3. Supplementation of ruminanta.
More investigations are needed to measure weight gain CJr
milk production allowed by supplementation of ruminants with
browses.Their secondary productivity measurment is of urgent
importance,to help to precise recommandations about their
utilisation.
A whole methodology of hrowse exploitation has to te
defined.It would include a time table and method of browses
harvesting ,species to be protected,storage and distribution
to ruminants as supplement.The case of direct utilisation in
pasture needs more research work to precise and control the
optimal stocking rate.
SO browses manadgement must take in account a11
constraints witch are technic and social particularlly.
. Harveeting: In addition to the pro]: 1 :If-
> Y i of methodc~logy ~
browse plants usage puts a problem of species collection and
optimal period of harvesting.
It is not easy to define a methodology of harvesting
appliable to a11 genus.Variations in phenological behaviour
justify a particular study of each genus or specie.The goal
is to exploit and allow browses to regenerate.Cutting leaves
and small branches seems to be a good method of harvesting
(Piot,iSSO).
Some species are high in nutritive while others are
uninteresting as ruminant fodder.An association of çhemical
and secondary production criteria should allow a definition
of species to be protected or introduced in pasture.
The choice of browse harvesting period is of major
importance.One must bear in mind that too early cutting cari
break the process of development of reproductive parts
1 7
_..
~_ _.....
.-.
(flowers and fruits).A too late cutting cari lead also t,o an
excess of lignification and a decrease in nutritive value of
trees and shrubs. Species variation in development cycle
suggest an adoption of different periods of harvesting
according to their phenology witch good knowledge is
required.
.Storage of harvested bromes: A good storage of leaves or
fruits of trees and shrubs cari overcome bioclimatic
constraints like fire,drought,wind and insect or birds
parasitism.So they cari contribute to limit under-nutrition
and nJcJrtality of rmi.rGmtE in the Sahel.
The depressive effect of suri drying upon nutritive value
suggests that ensiling should be tested with local tools.
, Direct utilisation in p&aturs:The free choice method
does net help in manadgement improvement in the present
conditions of sahelian livestock with large movement of herds
during the dry season,resulting in a disordered natural
pasture exploitation.Some species may be menaced for
suppression because of over-grazirig,encouraging development
of uninteresting others.
Determination and control of adequate stocking rate could
minimize the constraints to direct utilisation of browses in
pasture.
2.4. Conclusion
Some browses are of high digestible protein level and
are available in areas of traditionna livestock in the
sahel.
Constraints to their optimal utilisation at the farmer
level involve variation in nutritive value,range management
as well as farmer low level of education.
Research about browse plants need to be intensified in
order to answer questions involving species choice and
collection including their secondary productivity.
CONCLUSION
Protein under-nutrition is the main constraint to
livestock productivity in the sahel.
Usual protein sources like oil meals or seeds,cereal
treatment by-product or brans of animal origin are sometime
expensive and not available in the area of production.
Research workers must face now the on-farm practical
utilisation of lower cost protein sources like browses or
urea.
The ability of urea to improve nitrogen level of
ruminants diet has been highlighted for many years.In
sahelian developping countries urea utilization at the farmer
level could help in protein supply and improvement of low
quality roughages.However research results are of poor
dissemination.
Constraints to introduction of that new feed technology
in traditionnal livestock involve risks of toxicity,water
deficiency,cost and availability of urea in rural areas,as
well as lack of equipment and low level of farmer education.
Farmers preliminary education is needed to teach them
appropriate feeding management for maximizing the profit of
urea diets supplementation.
Some resarch area need to be carried out on-farm to
precise recommandations about locelly available tools
usage,urea-straw ensiling time and economics of urea on-farm
utilisation as a new feeding technology in rural zones.
Optimal utilisation of browses requires a better
knowledge of their nutritive value,technic of harvesting and
secondary productivity.In addition to those technical
constraints the problem of range management needs to be
investigated.On-farm research efforts should be directed on
farmer education for environment preservation.
SUMMAE?Y
Studying the problem of protein supply of traditionnal
livestock in the sahel,c~~nstrainta to urea and browse plants
usage at the farmer level has been highlighted.
In the case of urea utilisation either as non protein
nitrogen source or reagent for low quality roughage treatment
r emphasized constraints involve it's unavailability as well
as difficulties in handling this potentially toxic compound.
Other limiting factors are water deficiency and low level of
farmers education in the sahel.
The main constraints to browse utilisation are in
relation to optimal range management and environment
preservation.Some technical points like species to be
selected their secondary productivity and toxicity,remain to
be clarified by more research work.
Farmers education appears to be of major importance in
2 1
’ i
the introduction of thuse new feeding technics.
Key worde: Prutein eupply,ruminants,urea,browses,constraints
BIBLIOGRAPHY
- DIAGAYETE 1981
Untersuc~hungen zur erweiterung der kenntnisse uber den
futterwert westafrikanischer futterpflanzen.
Dissertation zur Erlangung des grades eines Dokters der
Agrarwissenschaften vorgelegt der facultat IV
-Agrarwissenschaften II- der Universitat Hohenheim 135~
- DICK0 M. S. 1980
Measuring the secondary production of pasture;an applied
example in the study of an extensive production system in
Mali.
1n:Browse in Africa the current stage of knowledge.Le
Houerou ed.ILCA 1930 pp 247-254
-$ALL Sm lS88
Utilisation digestive par les ruminants domestiques de
ligneux fourragers disponibles au Sénegal.
Rapport ISRA-LNERV No 59 Ali Nut.Sept 1988 1OOp
FALL S.,CIUERIN H.,SALL C.,M'BAYE ND. 1987
Les pailles de &Gales dans le systeme d'alimentation
des ruminants au Sénégal.
Rapport ISRA-LNERV No 70 Sept 1937 68~
GUERIN H.,RICHARD D.,FRIOT D.,M'BAYE N. 1985
Le choix alimentaire des bovins et ovins sur paturages
sahéliens.
Rapport ISRA-LNERV No 49 Ali.Nut. Fev 1985
GUERIN H.,RICHARD D.,FRIOT D.,KONE A,R.,avec la collaboration
technique de A.DUCHE,P.LEFEVRE,G,EERNARD et M-EL DJENDOUBI
1988
Interet du dosage de la lignocellulose(ADF)at de sc~n
azote résiduel pour estimer la valeur nutritive des fourrages
naturels sahelien. A paraitre.
HENTGEN A. 1985
Les arbres fourragers en 1nde:une chance pour l'elevage
des ruminants.
Fourrage No 191 Mars 1985 pp 105-119
JACKSON M.G. 1979
Le traitement des pailles pour l'alimentation des
animaux.Evaluation de la rentabilité technique et Economique.
Etude FAO:Production et Santé animales.No 10. 68p
KONE A.R. 1987
Valeur nutritive des ligneux fourragers en zone
sahhlienne et soudanienne d'Afrique occidentale:Rec~herche
d'une methade simple d'estimation de la digestibilit6. et de
la valeur azotée.
ThGse Doct 3&me Cycle.Univ.Paris VI Dec 1987 150~
LE HOUEROU 1980
The role of browse in the sahelian and soudanian zones.
in:Browse in Africa the current stage of know1edge.H.N. LE
HOUEROU ed ILCA 1980
MC LEOD 1974
Plant tannins their role in forage quality
Nutr.Abstract and review.Vol.44 No 11 NOV 1974 pp 804-815
NRC 1976
IJrea and other non protein nitrogen compouds in animal
nutrition.
NAS.Comitee on animal nutrition.12Op
PIOT J. 1980
Management and utilisation method for ligneous forage:
Natural stands and artificial plantations.
1n:Browse in Africa.The current stage of know1edge.H N. ed
ILCA 1980 pp 339-349.
24
Matchii-g livestock systems to available feed resouroes .
Penambul books ed pp 141-196.
REED J.D.,HOVARTH P.J.,ALLEN M.S.,VAN SOEST P.J. 1385
Gravimetric determination of soluble phenolics inoluding
tannins from leaves by precipitation with trivalent yterbium.
J.Sci.Food Agric. 1985,35,255-261.
REYNAUD Y.P. 1958
De l'utilisation de 1.uree dans 1 * alimentation des
ruminants domestiques.Toxicologie.
These Doct.med.vet.No7 Fac Med Pharm Toulouse.Fev 1953 123~
SUNDSTOL F 1984
Définition des procedures a suivre pour les recherches
sur le traitement des résidus de recolte et sous-produits
agro-industriels dans les pays en developpement.
In: Rapport de la consultation d'expert FAO/CIFEA Addis Abebe
5-9 Mars 1934 p 36
25
____-_-__--_-___----___________I________--~--~~-~~~~~~~~~~~~
.
.
YEAR
.
--------------------------------------
*
.
”
.
1986 .
1987
'
1988
.
.
.
.
--
- - ------------
1
Total requirement *
17000
17000 .
:for soi1 improvement:
.
(tons)
'Imported quantities**
10000 .
8000
(tûns)
'Price(Tax free) *
60
60
CFA/Kg
Government contribu
24
.6
.
8
:tion CFA/Kg *
Dakar price **
70
-
7 0
7 0
: CFA/Kg
Rural market price
75
75
75
: CFA/Kg
Requirement for
:ruminants supplemen
171550 :
tation (tons
_______________
_--- ----. -- .--, _--.-------------
.--- -._------- ___._. ___
Sources: * Ministry of rural development
** Senchim
*** our estimation:ZOg per head of small ruminant
20Og per head of cattle
Table 2: Nutritive value of cereal straws (Fall et a11 1987)
* g/Kg dry matter - - . - - - - - - - - - - - - _ - _ ._ _ _ - - - - - - _ _. _ _ _ _ _ _ __ _ _ _ ,_
: &&&&y ;;&&,y - :
.tion,digestibility. Rice
Maize
Millet :Sorghum :
and intake.
straw (N)'straw(N=l' straw (N) straw(N=3)
* -------- ---------- * ----- ---- * ---------. -------_ _- *-- l_l_.____ *
:Organic matter *
: 827$19( 29)
751
:886i43(5): 914st29 :
:Crude protein
JC
,
:25*13(29):
36
:60~15 (5):
39f9
:
:Crude fiber
*
: 360334(29):
251
:397$55(5):344*31
:
: NDF
*
:555 (1) :
618
:814+83(3): 708k36 :
: ADF
t
:428 (2) :
316
:518257(3):
4381;26
:
: Lignin
*
:62 (2) :
55
:96fl9 (3): 58;t5 :
: Silica
t:
-
107
:43f41 (4): 32f13 :
: Calcium
*
:1.9 (2) :
1.1
:3.1f2.2(5: 2.7jzO.2 :
: Phosphorus
,.
*
: 0 . 7
(2): 0 . 5
:1.8&1.1(5: 0.46&CI.12:
: Magnesium
k:
-
:
0 . 9
:4.l;tO.l : 3kO.4 :
: Potassium
*:
-
:
0 , 4
:93f98 (3): 8.2k3.1 :
: Cobalt ppm
0.76
:Cl.GfC).l ": 0.34;tO.O7:
: Copper ppm
17.9
:6.5&1.7 ": 3.liO.6 :
: Zinc
mm
76.5 : 29.4+5.0":18.1&7.5 :
: Manganese ppm : - :
50.3
:107.8+13.3 195&27 :
: Sodium
ppm :
-
:
2525
:575&414
:757+307 :
:Dry matter digesti:49+3 (15):
48 (1): 37 (10): 44
bility(sheep) pi00 .
Organic matter
:digestibility : 58
39 : 38 : 46
(sheep) ~100
.
'Intake g/Kg ~0.75
sheep
48
*
-
- 34
' 39
cattle
74 .
- .
-
-
_
______________- ----- --.-- --- ---<---------... -._ ----- --If---- .--.-.--.-
.
: Dry rriat,ter
:rky matter :
Crude protein Digestibility
intake
pi00
: 1-100
-----.------II----___I-.--____
-.-_
Urea 5~100:
.
ensiled
79
54+4 (N=6) - 61+10 (N=6)'
Rice straw
Control
43+4 (N=6) . 48+3 (N=!!i) .
- -----.---- ----__---- --
--- -_
------. --_.-- :-- -- ----- ___. *
ensiled
urea :
57-r-5
(N=6) : 531-10 (N=6):
5plC)O
Maize straw
Control
39
49+2
(N=6) '4t)+5 (N=6) *
*-----_--_----__--_
*_ -- ------ - --- *_ ------ ------ *__-__-_--_^--
ensiled:
141
59+6 ( N=6)
:56+3 (N=4) :
urea
5p100 :
Millet straw
Control:
84
39+6 ( N=5)
: 311-7 (N=4) :
-------------------- -- ------ - -_“--- ------ _----- -1-1---------
ensiled:
urea
146
65+3 (N=6)
68+3 (N=6)
5plOC) :
Sorghum straw
Control:
42
47+5 (=2) :
50+6 (N=5)
.
S a h e l i a n F e r l o area : d r i l l i n g d i s t r i b u t i o n i n S e n e g a l
$ d r i l l i n g
Source
: Gaston 1987
i----l
Livestock zone
Millet and sorghum area
~Cil Area of rice cropping
CMaize area
Cap
V e r t
J
00 km
REPUBLIQUE DU SENEGAL
MINISTERE DU DEVELOPPEMENT RURAL
iBil INSTITUT SENEGALAIS
DE
RECHERCHES AGRICOLES
Communication presented at the PANESA/ARNAB workshop
Malawi - December 5-9 th 1988
by Safiétou Touré FALL
Direction des Recherches
sur la Santé et les Productions Animales
IMPROVEMENT OF NITROGEN LEVEL IN RUMINANT?S DIET
The problem of dissemination of research results on
utilization of urea and browses as nitrogen sources in
sahelian feeding systems.
Contribution presented at the PANESA/ARNAB workshop
Malawi. December 5-9 1988
BY
Dr Safietou Fall
ISRA LNERV
BP 2057 Dakar
Senegal
1
t
INTRODUCTION
Bioclimatic contraints are still the main limiting
factor to food availability for ruminants in the sahel.
The dissemination of available research results wich
propose well adapted solutions to those difficulties is of
particular urgency.
Cereals as well as high energy and nitrogen concentrates
remain costly with additionna1 problems of transport and
livestock is in competition with others alternative usages.
Some high nutritive value agro-industrial by products are
exported;thus their availability is poor.
SO in sahelian countries ruminant feeding systems are
naturally based on natural pastures and low quality roughages
like cereal straws witch are good sources of cellulose but
low in digestible nitrogencsee table Z).Chemical and/or
physical treatment including nitrogen,energy and minera1
supplementation are indispensable for optimal utilisation of
low quality roughages.
Among nutritionnal constraintsprotein deficiency
appears to be one of the most important.Protein sources are
expensive and some proposed solutions involving utilisation
of oil meals and cereal brans seem to be of poor apliability
at the great scale of extensive livestock.For that purpose
urea and browse plants could be of a good help as locally
available and cheaper nitrogen sources.
Over more than 50 past yearsresearch works on protein
2
-
_.._
..-
---
.--.----
--
_--- _.-.-
-- --
-..
~..___
.. ,.-...
“-_ ._
c
ruminant nutrition have identified urea as the most promising
chemical for cereal straw quality improvement and non protein
nitrogen supplementation(Jackson 1979 > Sunstol 1984).However
research results have been of poor dissemination in African
traditionnal livestock.
Rrowse plants are other source of protein readily
available in pastures.During the dry season they cari reach 50
per cent of the cattle diet while they represent the basis of
small ruminants nutrition(around 80 per cent of their diet)
(Guerin et a1 1985),in grazing conditions.Available
informations describe the nutritive value of trees and
shrubs;their high protein content and aptitude to enhance
nitrogen level of ruminants diet is emphasized (Rivière
1978,in Le Houerou 1980,Kone 1984,Kone 1987,Fall 1988)
SO urea and browses give
good possibility to limit
nitrogen deficiencies in Sahel and improve livestock
productivity.
Our objectives is to highlight several considerations
linked with practical dissemination of research results,to
identify constraints and propose some solutions able to make
easy nitrogen supplementation of low quality fodder using
urea and browses at thé: farmer level and find out some on
farm-research areas in relation with urea and browses usage
witch need to be investigated in priority.
3
‘
1. Constraints to urea on farm utilisation in aahslian
countries
1.1. Urea for nitrogen supplementation of ruminants diet
1.1.1. Urea availability (Sec table 1)
In most of the sahelian countries urea is not locally
produced.This chemical is imported and widely used as
fertilizer.In Senegal around 10,OCJO tons per year are
imported and manufactured for fertilizer production.This
quantity is bellow the national requirement for soi1
improvement and urea usage in livestock feeding could
increase the deficit.
Governement contribution to urea cost is decreasing from
a year to another.The ob3ective is to suppress this
contribution for priva-te initiative resulting in a decrease
in urea distribution.
SO availability and cost of urea is a major constraint
to it's popularization.More quantity is required for both
livestock an soi1 produtivity improvement.
The question is weather urea supplementation is
feasible and profitable in the conditions of extensive
livestock or not.On-farm trials and economics could help to
prove it.
4
1.1,2.2 Caracteristics of urea added diets.
To optimize urea digestive usage a good supply of energy,
true proteins and minerais is needed.
- Easily digestible source of energy is needed.Molasses
and cereals are good supports of urea.The first is available
in areas of sugar cane prodution while the second suffers for
monogastric (including human) nutrition competition.
-Urea mixture in the diet has tu be the most homogenous
possible tu ensure a progressive consumption by the ruminant.
This aspect involving the diet preparation EJay be
constrainting for farmer Since urea iS sold in Pearl form.It
has to be solubilized in water before to be mixed with the
other coIrJporJentE of the diet.This imply a good water supply
but also a blendor or a hand mixer like fork to impregnate
forage with urea solution.
-In addition to urea supplement,true proteins are
required for a well balanced rations .According to NE?C (1976)
estimates urea level should not be above 30 to 40 per cent of
the protein requirement of the animal.So urea cannot solve
the whole problem of nitrsgen requirement in protein
deficient diets.
-Minerais specially calcium and phosphorus(in a well
balance)including sulphur and cobalt are required for optimal
activity of rumen microbes the true users of urea.
It puts the problem of availability of minera1 supplements
6
.
in acceptable price in rural area.A practical solution has
not been reached yet at the large scale of traditionnal
livestock.
-The water availability in the sahel is the most
important constraint to urea utilisation.The watering of urea
given animals should be as regular as possible and it is
advisable to give water at libitum.This is almost impossible
in the sahelian traditionnal system.
Temporary water points dry in the early dry season.
Drillings have a hard problem of maintenance;they do not work
often and the distance between them in ferlo area is too
high(See figure 2 Gaston et a1 1987) So herds use to be
watered once every two days.In this system water supply does
not satisfy ruminants requirements;those conditions do net
seem to allow urea introduction.
Beef fattening workshops around agglomeration where water
supply is correct offer best conditions to spread research
results involving urea usage in ruminants diet.
-Yoor palatability of urea added diets may be a
constraint to it's acceptance by ruminants.Molasses and/or
salts are excellent supports for improvement of urea added
diets palatability
Caracteristics of urea based diets summarizes some rules
to be respected in order to ensure a good absorption and
prevent ammonia intoxication.Farmers need to be aware of
them.
7
1.2. Improving nutritive value of lew guality rsughergss by
urea processing
1.2.1. Urea versus other chemical or physical methods of
straws quality improvement.
A major limiting factor to straws utilisation is their
bulkiness and low concentration in digestible nutrient.Their
nitrogen poverty specially has a negative effect upon their
digestibility.
Several methods have been used to improve intake and
digestibility of straws.
Physical treatment by chopping or milling has the
drawback that they may be costly in energy and need some
equipment.Rice straw is less rough and does no-t need to be
chopped on farm.Hand cutting with a chopper is suitable for
sorghum and milled straw to make them easily edible.
For chemical treatment of low quality roughages,several
alcaline or acid reagents are proposed.Among them the
ammoniation by urea offers greater promise in the viewpoint
of feasibility,with an added advantage that it supplies non
protein nitrogen(Jackson 1979,Sundstol 1984,Fall et a1 19871,
and that it is more accessible a-t the farmer level compared
to other chemicals.Urea is three times cheaper than sodium
hydroxide wich is not available in rural zones in Senegal for
8
example.However his usage is not without any constraint.
1.2.2. Technical constraints to dissemination of urea
treatment of cereal straws
In addition to urea availability and potential toxicity
of ammonia as described previously,there is a need tu Select
an adapted technical procedure in tropical conditions.
1.2.2.1. The method of strarw trsatment
available methods (Jackson 19791 are based on the
mixture of straw and urea at the level of 5 per cent.
In the dry procedure,urea is injected in the straw using
high pressure.After injection temperature raising seems to
give best forage quality(Jackson 19791.The cost and
availability of the needed equipment makes that technology
out of reach for sahelian farmers at the large scale.
The second way involves a small quantity of water.A 5
per cent urea solution is spread over the straw at the
proportion of 1 liter of solution per kilogram of straw to
make it reasonnably humid (sec Fall et a1 1987).The urea-
straw mixture is kept in a silo and left for incubation for
two (in tropical climate)or six weeks(in cool climate).This
way seems to be advisable in drought conditions of sahel.In
addition it prevents from risk of environment pollution.
IJrea ensiling leads to improvement of intake
9
digestibility and nitrogen content of poor quality roughages
(see table 3).However it should represent .a restricted
proportion of the ruminant diet to avoid risks of ammonia
5
toxicity for beef cattle or transmission of toxic compounds
in milk for dairy cattle(Perdock and Leng 1987,Preston and
leng 1987).In north Europe treated straw does is usually
above 30 per cent of the diet(Preston and leng 1987I.More
research work are needed to evaluate accurately the daily
optimal consumption of urea treated straws for sheeps and
cattles in Africa.
Urea ensiling method seems ta be of easy
application;however some adaptations to rural conditions are
needed.
1.2,2.2, Adaptation of urea enrilinreg metiled te rura%
conditions.
Availability of suitable eqlAipKJerJt in traditionnal
livestock areas is a serious constraint to popularization of
straw ammoniation by urea treatment.One should try to use
locally available tools.
-Straw physical treatment
Before urea ensiling long cereal straws have to be
chopped in order to make them easy to handle and the reagent
reach the ce11 wall.Most of the choppers are more or less
sophisticated and working with electricity witch may not be
available in rural areas.
II_“_--- -....- -
---. I .
Fe of agood help.Total isolation of t,hF-silo'ls a probTem.
--.
The chopping process may be done by hand with a hatchet.
Rice straw is less rough and does not need a reduction of
length.
-Tools of treatment.
IJrea solution cari be sprinkled by watering caris.
Instead of big containers made of metal like it is used
in North Europ,straw cari be urea ensiled in a silo hollowed
out of soi1 and covered with a lay of cernent or clay.
After urea solution-straw mixture the silo cari be
covered by a polyethylen tarpaulin wich cari be non available
in certain zones.In this case banana or palm trees leaves cari
be of a good help.Total isolation of the silo is a problem.
With local tools it may suffer for some gas ammonia escape.On
farm trials should precise the negative effect of loosing
ammonia through the silo.
-Ensiling time.
Although the treated StraW IYJay be of long COnSerVatiOn
in the technical viewpoint,ensiling time may be a constraint
for small scale farmers.They may not have capacity to treat a
great quantity of straw once,and prefer to treat the required
amount each week.Reported optimum ensiling time are from 10
days (in warm climatej to six weeks (in temperate countries).
Reseach efforts should be directed to studies about the
influence of decreasing ensiling time upon in the extend of
straw quality improvement.
1 1
-- . .._--_...
-..-
b.v
1.2.3. Cost of urea treatment of straw
As discussed previously,the cost and availability of
urea in rural areas are the ma.jor constraint to its
utilisation.
An estimate of treatment cost in the area of rice
production leads to triplicate it's price witch goes from 15
to 45 CFA per kilo.
Triais involving the study of milk or liveweigt gain cost
in the case of urea ensiled straw usage are scarce in
sahelian countries.
Economies of straw ammoniation by urea should be a major
on farm research work in order to precise the profit and
convince farmers about the reliakJili.-ky of the technic.
1.3. Conclusion,
Ability of urea to enhance nitrogen level of ruminant's
diet either as supplement or as chemical reagent for low
yuality roughages improvement has been proved for many years.
In sahelian countries dissemination of available
research results is limited by,a lack of suitable
eyuipment,the poor availability of urea in rural area,it's
high price and potential toxicity by quick ammonia intra
rumina1 release.
More on farm research could find solutions to technical
constraints and propose feaaible adaptations in rural areas.
1 2
Farmers training is one of the first problem to solve
before urea introduction in sahelian feeding systems.
II. Constraint to browse plants utilisation in ruminants diet
in the Sahel.
Recent results have shown the importance of trees and
shrubs in ruminants feeding in africa(in Le Houerou 1930).
In natural pasture they cari reach 70 to 30 per cent of sheep
and goat's diet during the dry season(Guerin et a1 1935).
Leaves,flowers and fruits of browses are well known for
their high level of nitrogen witch improves ruminant's
protein supply (in Le Houerou ed 1930,Kone 1934,Kone
1937,Fall 1933).
Consumed browses involve around 100 species(Le Houerou
1930).In the senegalese sahelian ferlo area the main genus
m-e Acacia,Balanit~~,Cal~tr~p~~~#~~~~a~~~~~~a,Zy~~~~~~
and
combretum.
Nutritive value.,harvesting and manadgement constraints
cari be a limiting factor to browse usage at the farmer level.
2.1. Nutrive value of browse plants,
2.1.1 Chemical composition.
Chemical composition of browses may be a limiting factor
13
--' ..
._-._._.
4
to their digestibility.Their high maturity explains the high
proportion of ce11 wall witch plays a negative role upon
digestibility.Part of the proteins may be imprisoned in
lignocellulose and make them unreachable by protein microbes
(Guerin et a1 1938) .So the total protein may not be
available.It depends on the degree of lignification,the age
and part of the plant.
Occurence of tannins in browses has been mentionned by
Mc Leod (1974),Diagayete (1983) and Reed et a1 (1985).Those
antiquality factors have a negative effect upon digestibility
and protein metabolisme specially.
Research efforts should try to identify the best period
of harvesting according to the stage of developpement and
part of the plant witch nutrient cari be really available.
Limiting factors tu browse intake are in relation with
chemical composition.Some species cari be rich in digestible
nutrient but not interesting in the pastoral viewpoint
because they are unpalatable.
Tannins and other toxic compounds play a negative role
on trees and shrub's palatability.Most of them remain to be
identified,their toxicity and seasonnal variations studied.
However browse intake varies according to the season and
year.In case of drought when food is scarce,ruminant are
hardless to please and accept scme bad taste species.
14
5
A long period of adaptation seems to improve browses
intake.
2.1.3. Digestibility and intra-rumina1 degradation.
A high proportion of ce11 wall and lignin fraction
contribute to lower digestibility of browses.The poor intra-
rumina1 solubility at a short time of incubation explains in
part,the low intake of some speeies (Fall 1988J.Some research
work could try to find out a feasible method of browse
ensiling to limit the negative role of ce11 wall.
2.2. On farm utilisation of trees and ahrubg,
2.2.1. Browse harvesting.
Most of the sahelian countries do not have a legislation
witch specify the way of natural pasture utilisation.This
judicial lack should be filled to allow farmer to be really
involved in range manadgement.
In addition the moving of herds looking for water and
food makes difficult a planification of pasture utilization.
SO browse are used freely in pasture.Some species are over-
grazed while others are not touched.Stocking rates are often
too high and bush fire is still destroying a great part of
pastures.
TO avoid those constraints,for a well planed utilisation
of available feed ressource farmers have to tut and save
15
-7
-
trees and shrubs for the hard period of dry season.
Technics of exploitation have been reviewed by Plot
(198O).%metime trees are entirely Cut down.That methsd do
net help regeneration and protection of environment.It should
be advisable to tut the upper leaves and alluw regeneration
of trees.
2 . 2 . 2 . Storage o f trese a n d ahrubs,
In the sahel sturage of browses as a fndder reserve is a
necessity.
Sun drying is easily applicab1e.Thi.s method is utilized
for most of the harvested Acacia fruits in west Africa.
However this procedure may have a negative effect upon
nutritive value of some species.
Ensiling with salt,used to store Alzadirachta indica
leaves(Hentgen 1985) seems to be a promising methcjd.However
training of farmers is suitable before introducing that
technology.
2.2.3. Supplementation of ruminanta.
More investigations are needed to measure weight gain CJr
milk production allowed by supplementation of ruminants with
browses.Their secondary productivity measurment is of urgent
importance,to help to precise recommandations about their
utilisation.
A whole methodology of hrowse exploitation has to te
defined.It would include a time table and method of browses
harvesting ,species to be protected,storage and distribution
to ruminants as supplement.The case of direct utilisation in
pasture needs more research work to precise and control the
optimal stocking rate.
SO browses manadgement must take in account a11
constraints witch are technic and social particularlly.
. Harveeting: In addition to the pro]: 1 :If-
> Y i of methodc~logy ~
browse plants usage puts a problem of species collection and
optimal period of harvesting.
It is not easy to define a methodology of harvesting
appliable to a11 genus.Variations in phenological behaviour
justify a particular study of each genus or specie.The goal
is to exploit and allow browses to regenerate.Cutting leaves
and small branches seems to be a good method of harvesting
(Piot,iSSO).
Some species are high in nutritive while others are
uninteresting as ruminant fodder.An association of çhemical
and secondary production criteria should allow a definition
of species to be protected or introduced in pasture.
The choice of browse harvesting period is of major
importance.One must bear in mind that too early cutting cari
break the process of development of reproductive parts
1 7
_..
~_ _.....
.-.
(flowers and fruits).A too late cutting cari lead also t,o an
excess of lignification and a decrease in nutritive value of
trees and shrubs. Species variation in development cycle
suggest an adoption of different periods of harvesting
according to their phenology witch good knowledge is
required.
.Storage of harvested bromes: A good storage of leaves or
fruits of trees and shrubs cari overcome bioclimatic
constraints like fire,drought,wind and insect or birds
parasitism.So they cari contribute to limit under-nutrition
and nJcJrtality of rmi.rGmtE in the Sahel.
The depressive effect of suri drying upon nutritive value
suggests that ensiling should be tested with local tools.
, Direct utilisation in p&aturs:The free choice method
does net help in manadgement improvement in the present
conditions of sahelian livestock with large movement of herds
during the dry season,resulting in a disordered natural
pasture exploitation.Some species may be menaced for
suppression because of over-grazirig,encouraging development
of uninteresting others.
Determination and control of adequate stocking rate could
minimize the constraints to direct utilisation of browses in
pasture.
2.4. Conclusion
Some browses are of high digestible protein level and
are available in areas of traditionna livestock in the
sahel.
Constraints to their optimal utilisation at the farmer
level involve variation in nutritive value,range management
as well as farmer low level of education.
Research about browse plants need to be intensified in
order to answer questions involving species choice and
collection including their secondary productivity.
CONCLUSION
Protein under-nutrition is the main constraint to
livestock productivity in the sahel.
Usual protein sources like oil meals or seeds,cereal
treatment by-product or brans of animal origin are sometime
expensive and not available in the area of production.
Research workers must face now the on-farm practical
utilisation of lower cost protein sources like browses or
urea.
The ability of urea to improve nitrogen level of
ruminants diet has been highlighted for many years.In
sahelian developping countries urea utilization at the farmer
level could help in protein supply and improvement of low
quality roughages.However research results are of poor
dissemination.
Constraints to introduction of that new feed technology
in traditionnal livestock involve risks of toxicity,water
deficiency,cost and availability of urea in rural areas,as
well as lack of equipment and low level of farmer education.
Farmers preliminary education is needed to teach them
appropriate feeding management for maximizing the profit of
urea diets supplementation.
Some resarch area need to be carried out on-farm to
precise recommandations about locelly available tools
usage,urea-straw ensiling time and economics of urea on-farm
utilisation as a new feeding technology in rural zones.
Optimal utilisation of browses requires a better
knowledge of their nutritive value,technic of harvesting and
secondary productivity.In addition to those technical
constraints the problem of range management needs to be
investigated.On-farm research efforts should be directed on
farmer education for environment preservation.
SUMMAE?Y
Studying the problem of protein supply of traditionnal
livestock in the sahel,c~~nstrainta to urea and browse plants
usage at the farmer level has been highlighted.
In the case of urea utilisation either as non protein
nitrogen source or reagent for low quality roughage treatment
r emphasized constraints involve it's unavailability as well
as difficulties in handling this potentially toxic compound.
Other limiting factors are water deficiency and low level of
farmers education in the sahel.
The main constraints to browse utilisation are in
relation to optimal range management and environment
preservation.Some technical points like species to be
selected their secondary productivity and toxicity,remain to
be clarified by more research work.
Farmers education appears to be of major importance in
2 1
’ i
the introduction of thuse new feeding technics.
Key worde: Prutein eupply,ruminants,urea,browses,constraints
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24
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De l'utilisation de 1.uree dans 1 * alimentation des
ruminants domestiques.Toxicologie.
These Doct.med.vet.No7 Fac Med Pharm Toulouse.Fev 1953 123~
SUNDSTOL F 1984
Définition des procedures a suivre pour les recherches
sur le traitement des résidus de recolte et sous-produits
agro-industriels dans les pays en developpement.
In: Rapport de la consultation d'expert FAO/CIFEA Addis Abebe
5-9 Mars 1934 p 36
25
____-_-__--_-___----___________I________--~--~~-~~~~~~~~~~~~
.
.
YEAR
.
--------------------------------------
*
.
”
.
1986 .
1987
'
1988
.
.
.
.
--
- - ------------
1
Total requirement *
17000
17000 .
:for soi1 improvement:
.
(tons)
'Imported quantities**
10000 .
8000
(tûns)
'Price(Tax free) *
60
60
CFA/Kg
Government contribu
24
.6
.
8
:tion CFA/Kg *
Dakar price **
70
-
7 0
7 0
: CFA/Kg
Rural market price
75
75
75
: CFA/Kg
Requirement for
:ruminants supplemen
171550 :
tation (tons
_______________
_--- ----. -- .--, _--.-------------
.--- -._------- ___._. ___
Sources: * Ministry of rural development
** Senchim
*** our estimation:ZOg per head of small ruminant
20Og per head of cattle
Table 2: Nutritive value of cereal straws (Fall et a11 1987)
* g/Kg dry matter - - . - - - - - - - - - - - - _ - _ ._ _ _ - - - - - - _ _. _ _ _ _ _ _ __ _ _ _ ,_
: &&&&y ;;&&,y - :
.tion,digestibility. Rice
Maize
Millet :Sorghum :
and intake.
straw (N)'straw(N=l' straw (N) straw(N=3)
* -------- ---------- * ----- ---- * ---------. -------_ _- *-- l_l_.____ *
:Organic matter *
: 827$19( 29)
751
:886i43(5): 914st29 :
:Crude protein
JC
,
:25*13(29):
36
:60~15 (5):
39f9
:
:Crude fiber
*
: 360334(29):
251
:397$55(5):344*31
:
: NDF
*
:555 (1) :
618
:814+83(3): 708k36 :
: ADF
t
:428 (2) :
316
:518257(3):
4381;26
:
: Lignin
*
:62 (2) :
55
:96fl9 (3): 58;t5 :
: Silica
t:
-
107
:43f41 (4): 32f13 :
: Calcium
*
:1.9 (2) :
1.1
:3.1f2.2(5: 2.7jzO.2 :
: Phosphorus
,.
*
: 0 . 7
(2): 0 . 5
:1.8&1.1(5: 0.46&CI.12:
: Magnesium
k:
-
:
0 . 9
:4.l;tO.l : 3kO.4 :
: Potassium
*:
-
:
0 , 4
:93f98 (3): 8.2k3.1 :
: Cobalt ppm
0.76
:Cl.GfC).l ": 0.34;tO.O7:
: Copper ppm
17.9
:6.5&1.7 ": 3.liO.6 :
: Zinc
mm
76.5 : 29.4+5.0":18.1&7.5 :
: Manganese ppm : - :
50.3
:107.8+13.3 195&27 :
: Sodium
ppm :
-
:
2525
:575&414
:757+307 :
:Dry matter digesti:49+3 (15):
48 (1): 37 (10): 44
bility(sheep) pi00 .
Organic matter
:digestibility : 58
39 : 38 : 46
(sheep) ~100
.
'Intake g/Kg ~0.75
sheep
48
*
-
- 34
' 39
cattle
74 .
- .
-
-
_
______________- ----- --.-- --- ---<---------... -._ ----- --If---- .--.-.--.-
.
: Dry rriat,ter
:rky matter :
Crude protein Digestibility
intake
pi00
: 1-100
-----.------II----___I-.--____
-.-_
Urea 5~100:
.
ensiled
79
54+4 (N=6) - 61+10 (N=6)'
Rice straw
Control
43+4 (N=6) . 48+3 (N=!!i) .
- -----.---- ----__---- --
--- -_
------. --_.-- :-- -- ----- ___. *
ensiled
urea :
57-r-5
(N=6) : 531-10 (N=6):
5plC)O
Maize straw
Control
39
49+2
(N=6) '4t)+5 (N=6) *
*-----_--_----__--_
*_ -- ------ - --- *_ ------ ------ *__-__-_--_^--
ensiled:
141
59+6 ( N=6)
:56+3 (N=4) :
urea
5p100 :
Millet straw
Control:
84
39+6 ( N=5)
: 311-7 (N=4) :
-------------------- -- ------ - -_“--- ------ _----- -1-1---------
ensiled:
urea
146
65+3 (N=6)
68+3 (N=6)
5plOC) :
Sorghum straw
Control:
42
47+5 (=2) :
50+6 (N=5)
.
S a h e l i a n F e r l o area : d r i l l i n g d i s t r i b u t i o n i n S e n e g a l
$ d r i l l i n g
Source
: Gaston 1987
i----l
Livestock zone
Millet and sorghum area
~Cil Area of rice cropping
CMaize area
Cap
V e r t
J
00 km