IT HAPPENS ONLY IN INDIA,
GREAT JOB MR. PARMAR
it is good to eat as many as vegetables and fruits (totally vegetarian), but my aurvedic doctor asked me to stop eating every...
Animals in industrilized countries both farmers and animals are
becoming specialized. Thus dairy farmers keep high
milk producing cows. Beef farmers keep specialized
beef animals - sheep are specialized in producing meat
or wool. Likewise the crops are specialized and crop
residues generally discarded or ploughed in.
This total market orientation lead to security in
homogeneity both of crop and animals.In the new case of
this is achieved by intensive selection using AI and embroyo
In developing or less industrialized countries the
environment cannot usually be controlled.As the animals
have many functions thus diversity has survival value.
Moreover, animals selected on the basis of homogeneity will not
fare well as it is simply illustrated by the many
failures of importations of 'upgraded animals'
from industrialized countries to less industrialised
The feed resources in crop livestock systems in less industrialized
countries. Only little attention will be given to the
animal product which are many and varied. In the case
of ruminants they contribute directly to human food in
terms of milk not meat products. They contribute wool,
hair and skin for clothing, carpets and shelter. Most
important they contribute indirectly to human food by
providing draught power for cultivation. They
contribute to threshing and transport. They supply
dung for domesticfuel, manure and building material.
As distinct from industrialised systems both animal
manure and crop residues are valuable resources.
Perhaps on a global scale the most important products
the animals produce is their role in providing security
and prestige and their important contribution to risk
aversion. Animals are often sold when cash is needed
for school fees and other important items. They can
often absorb excess labour as more feed can be
collected when labour is available. The most important
animal products are so to speak maintenance and
survival. Many of the products mentioned above can be
substituted by fossil fuel such as draught power if
this was economical and more feed could be used for
production of milk and meat. The animals role in
security and risk aversion can only be changed by long
term political and economic stability.
Regardless of product there is a finite amount of feed
resource available. In the following emphasis will be
given to feed used in crop livestock systems rather
than in rangeland systems as there is probably more
possibilities to enhance utilization and feed
availability in such systems.
Crop residues constitute the major component of feed
for ruminants in almost all small scale crop livestock
systems e.g. straw from rice, wheat, barley, stovers
from maize, sorghum and milet and stalk from ground-nut
sweet potatoes etc. bagasse and molassis are available
in suger can areas. In some areas small amounts of
cultivated forage are available. A limited amount of
higher quality crop residues are available such as
wheat, rice and maize browse and leaves from trees and
bushes and city by products such as brewers grains. A
small amount of grazing along roadside and edges of
fields and ponds in also available and in rainfed areas
the fields can be grazed in the dry season.
The simpler and cheapest way to improve crop residues
would be if it could be done by genetic selection.
Here there are real and almost totally unexplored
possibilities. Plant breeders have hardly ever taken
quality of crop residues into account in selecction
indicies. Thus the International Rice Research
Institute in the Phillipines pay no attention to
quality of straw.
In the past there were some good reasons for this
because straw quality was difficult to measure rapidly.
It could only be done by large scale digestibility
trials in which groups of animals were put into crates
and their excreta collected. such difficulties no
longer exists. Biological methods are now available
which can rapidly and reliably test quality of crop
In 1986-87 The International Feed Resources Group in
Scotland tested up to 100 varieties of grain from
wheat, barley and oats. The quality of barley and
wheat in particularly showed wide variations. In fact
the variability was such that groups of cattle grew 300
g/d more from consuming one variety of straw than
another. such work has now been published also from
Indonesia using rice straw, from India using variation
of rice straw and sorghum stover, and from Syria using
barley straw varieties, to name but a few.
A negative correlation between grain yield and straw
quality has never been reported so the 2 aspects can be
selected for at the same time. It is worth pointing
out here that farmers have been known to reject new
varieties of grain due to the poor quality straw or
stovers they produced! Crop residues are very important
for most farmers in crop livestock areas.
Are the causes of genetic variability due to
differences in botanical fractions or due to
differences in quality of individual fractions?
Cereal straw contain essentially 4 separate fractions,
the stems, the leaves, the nodes and the chaff (from
the flowering parts). the latter two fractions
constitute about 15%. Of these fractions the leaf is
by far the most the digestible except for rice straw
and the stem the least digestible. rice straw is an
exception as the stem is more digestible than leaf.
the smallfraction of nodes and chaff are intermediate.
It is thus possible to alter the quality by selecting
for a greater proportion of leaf in the straw. In most
examinations of genetics variation in straw quality
differences in leaf to stem ratio have not been nearly
so important as differences in quality of the
individual components. This is interesting. Oftern
there are no differences in the lignin content which is
the products that holds it together but there seem to
be differences in the architecture of the straw. It
could be tempting to ask whether straws of high
nutritive value would also be prone to lodging but
there is no evidence for that.
The digestibility of straws and stovers (Stovers are
the same for straw from maize and sorghum and millet)
is normally between 40 and 50%. Differences in
digestibility of 10% may not seem much but it can have
pronounced influence as to how much the animal can
consume. sometimes they can eat 30 to 50% more even if
the differences were only 10% units in digestibility
and therefore cause large differences in performance of
the animals. In spite of the large differences in
straw quality reported for all cultivated grain
varieties there is still an unwillingness of plant
breeders to pay attention to this. If in India and
Bangladesh for instance with such large cattle
population an increase in digestibility of crop
residues by 10% was possibles at little or no cost it
could have a revolutionary influence on animal
It could be argued that if the leaf fraction was so
much better than stems, then if there was surplus of
straw it would be best if the leaf fraction could be
fed and the stems discarded. In effect small ruminants
like goats and to a lesser extent sheep do just that.
they are reluctant to eat the stems and can to a large
extent select the leafy parts. So if sheep and goats
are given say two times as much straw as they consume
they can achieve quite a high performance as what they
have eaten is high quality feed.
In some industrialized countries there is a desire to
do wthat separation for another reason altogether. The
reason is that the stem fraction is almost like wood in
chemical composition and therefore very suitable for
paper and hardboard making while leaf is not, but
fortunately leaf is best for the animals. A
fractionation thus add value to both fractions. From a
future perspective this opens up possibilities for
plant breeders not only to select for the highest
quality for animal feed but also the highest quality
for industrial raw materials. High nutritive value of
leaf in again not correlated with industrial quality of
stems. A separation method often used by small farmers
in Indonesia and China for maize stover is to remove
the leaves for feeding to animals and use the stalks as
The digestibility of
straw is about 40 to 50% and the reason for the low
digestibility is the lignin which prevent bacteria in
the stomach from penetrating it. Thus if the lignin
could be loosened or dislodged then digestibility could
at least theoretically be about 90% as the indigestible
lignin amounts to about 10%.
Upgrading can be done by alkali which swells some of
the lignin bonds so more cellulose and hemicellulose is
exposed to bacterial action. Caustic soda was used in
Germany already during the first world war to make more
feed available for animals. Caustic soda is a strong
alkali and generally the most effective but it has
little or not practical application due to the danger
in using it and the environmental consequeces of high
sodium levels. However the much weaker alkali ammonia
is applied in many places.
In industrialized countries
it is either gaseous ammonia or ammonium hydroxide as
industrial suppliers provide the chemicals in tanks to
large farms. for small farms however another product
has become much more popular namely urea. When urea is
hydrolysed ti yields ammonia. Urea is a relatively
harmless substance it dissolves easily in water and can
be applied to small quantities of straw. The level of
inclusion is about 5 kg urea/100 kg of straw. The
stack needs to be covered with mud, plastic, banana
leaves, planks etc., depending on local availability.
Several million Chinese farmers are now using this
method but also some Indian, Bangladeshi and Iranian
farmers. digestibility is usually increased by about
10% unit. The treatment is complete in 10 to 20 days
depending on external temperature (the method cannot
be used during very cold periods).
Due to the importance of this method for small scale
farmers in developing countries it is perhaps worth
just to discuss one more aspect namely the economy of
using urea/ammonia treatment. However, there are certain conditions which must be present before one can recommend this intervention to farmers.
First of all urea has to be available all the time.
Secondly the price of urea has to be such that making
straw more digestible is the cheapest option. Let us
say that 5 kg urea generated 10 kg of digestible matter
from 100 kg straw which imply 1 kg of urea generates 2
kg of digestible matter. If high quality material such
as rice bran cottonseed etc. can be bought cheaper and
with less labour then urea treatment should be
advocated. If there is a surplus straw then the urea
treatment enable the animals to consume sometimes 30 to
50% and a much higher performance can be achieved. It
was the surplus straw and high demand for beef which
has made treatment such an attractive medhod for small farmers in China.
Instead of swelling the bonding to
lignin it is possible to oxidize it with use of for
instance hydrogen peroxide in alkaline solution. Use
of peroxie has the advantage that the oxidation product
is water. this method is far too expensive. The same
can be said for acid treatment of make straw more digestible.
The use of a white rot fungi which
supposedly utilize lignin has been tried in many places
including NDRI Karnal Haryana. The problem is that too
much substrate is lost. The fungi uses from 20 to 40%
of the substrate in order to make the remainder a
little more digestible. Such methods need to be
combined with production of human food from the
fruiting bodies of the fungi such as pleurotis
Use of enzymes
A great deal of progress has been made
in isolating enzymes for exogenous degradation of
straw. Mixtures of xylanases and cellulases are used.
so far exogenous enzymes cannot break down substrate
which is protected by lignin. It has the potential to
generate soluble sugar from cellulose which in turn can
ferment to fermentation acids and make ensiling of
straw possible. Perhaps in the future it could be used
as a method of preserving wet harvested rice straw
which is often wasted.
Setting fields of paddy straw and
other crop residues knowing, that it could be used as
animal feed with resultant manure which could be used
as fertilizer for better than ashes from burned straw.
During some harvest the paddy straw needs to be dried
or otherwise preserved. The problem is often one of
labour and another crop needs to be planted. Here it
should at least be mentioned the urea treatment
described above also achieve to preserve the straw as
the ammonia generated prevents mould development.
In many areas particularly in Africa stovers from maize
sorghum and millet are grazed by animals in the field
and the remainder ploughed in for next harvest. when
the maize cob is removed the stalks are often still
green and considerably higher nutritive value than it
is later when the soluble material is the green stalks
has disappeared. There is a need here to develop new
methods of preserving stovers in such a way that the
maximum amount of nutrients are retained.
On small farms in China what is called maize silage is
actually silage made from talks after the cob has been
removed. there is room for innovative methods of
drying green thick stalks which also include cultivated
foragee like Napier grass which sometimes provide
excessive biomass in the wet season. The quality of
such biomass deteriorate when it is more than 1 m high
so methods of drying or preserving thick green stemmed
material is needed.
Supplements are here understood products of higher
quality which may or may not be produced on the farm
but often produced at small village mills such as rice,
maize or wheatbrans cottonseed, mustard seed, noug
cakes and many more. In sugar can areas molasses may
be available for feeding.
Here we must again consider that crop residues by
definition is not whole crop it is therefore like that
they are deficient in some nutrients since the main
product like grain have accumulated the essential
nutrients necessary to accomplish germination.
Supplements are therefore critical in so far that they
must contain if possible the limiting nutrients in crop
residues. In most instances the limiting nutrient is
nitrogenous compounds which can yield ammonia for the
bacteria in the rumen. If this is limiting, the speed
of digestion will be reduced and due to longer time in
the rumen the animal will eat less and digest a smaller
proportion. Alleviating that can have dramatic results
on straw utilization.
Another aspect of crop residues which often limits it
utilization is that even if there is adequate nutrient
for the bacteria they may grow so slowly on poor
quality feeds that the number of bacteria in solution
in their rumen limits the speed at which new feed is
being colonized and therefore degraded by bacteria to
produce short chain fatty acid. As a result intake and
digestibility can again be limiting. To alleviate that
however the supplement must also be cellulosic or
fermented by the same bacteria as those fermenting
There are many of these products about,
to name but a few, brans are namely cellulosic, leaves
from trees such as glyricidia jackfruit, leucaena etc.
cottonseed cake also contain cellulosic energy. Some
supplements such as tree leaves, has an excess of
protein which when fermented yields ammonia. Young
roadside grass can be an excellent supplement to straw
diets something in any case farmers have routinely for years.
The correct supplement could possibly
relieve both deficiencies as well as being utilized as
a nutrient in its own right. The net result is that
the responses to small amounts of the correct
supplement can be much greater than expected as they
help to utilize the basal feed better as well as being
a nutrients themselves. Molasses however cannot be
used for that purpose as it is fermented by a different
microflora though it is often being used as a carrier
I would like to complete this little article by a few
comments on livestock-crop interaction. There is no
doubt that excessive number of livestock can be
destructive but in cropping areas this is seldom the
problem. Livestock by consuming crop residues provide
a large number of services as mentioned earlier and in
many instances the manure is better fertilizer than the
crop residues. I am reminded of the work in Sri Lanka
by Pathirana (K.K.Pathirana, University of Ruhuna, Sri
Lanka), who showed that by grazing cattle under
coconut, coconut yields increased. By supplementing
the cattle with straw and brans the cattle produced
almost one calf/year and coconut yield increased still
Cattle grazing causes an increased rate of
return of soil nutrients from bioareas to soil and thus
increases soil fertility and coconut yield. There are
no doubt a multitude of examples like that. Here
however, people from industrialized countries have
little to teach and much to learn.