Dr. Waqas Nawaz PMAS arid agriculture university rawalpindi pakistan

1. Urea treatment of
wheat Straw

2. Wheat Straw as animal feed
 poor quality dry roughage
 given to the cattle (ruminants) as fillers
because straw hardly has any feeding
value
 highly deficient in minerals, vitamins,
proteins
 DCP=0.0; TDN=48.3

3. Digestive utilisation of straw
 Straw has Parietal carbohydrates in
their cell wall
 The microbes in the rumen colonise
the ingested feed particles
 The cellulolytic strains partially
degrade (or hydrolyse) the cellulose
and the hemicelluloses through using
the enzyme, cellulase

4.  The degradation of the cell walls
requires the microbes to attach
themselves to the feed particles so that
the enzymes can penetrate inside the
fibrous structures, hence the need for
the microflora which secretes these
enzymes.
 But wheat straw shows a high
proportion of lignified walls, incrusted
with lignin in a very complex manner

5.  the lignified walls resist for a long time
the microbial degradation and the
peristatic mastication (of rumination)
and they are thus only digested slowly.

6. Conditions for good digestive
utilisation
 In order for the cellulolytic fermentation
process to be correctly carried out, the
microorganisms in the rumen must be
able to find
• the nutritive elements which they need for
self development and to enable them to
degrade (through cellulolysis) the
polysaccharides of the cell walls of the
wheat straw

7.  the physical and chemical conditions for
maintenance of good cellulolysis.

8. Importance of wheat straw
 fibrous in nature
 Generally low in digestibility
 produce laxative effect after absorbing
more water from intestine.
 cheap and readily available source of
energy to the animal body

9. Need for urea treatment of straw
 To increase nutritive value (protein
source as in rumen microorganism
convert nitrogen into protein) of wheat
straw
 To increase digestibility of
wheat straw

10. Urea treatment: principle
 CO (NH2)2 + H2O -------> 2 NH3 + CO2
urease
urea +water ammonia+carbonic gas
 Once hydrolysis is completed
 one molecule of urea(i.e. 60 g) generates two
molecules of ammonia (i.e. 34 g).
 5 kg of urea thus allows production of 2.83 kg
of ammonia.

11. Urea treatment : process
 Three ways of urea treatment
– Treating small quantities within walled
enclosures
– Treatment of large amounts of forage in
stacks or heaps
– the use of urine

12. Convential method of urea
treatment
 Weigh the urea about 4% of straw.
 Prepare the urea solution (30-50%)
 Sprinkle the urea solution on wheat
straw
 Press the straw and seal in the plastic
bag or silo or pit or trench

13. Procedure(new method)
 Weigh the required amount of urea (4%
of straw)
 Mix it with double the amount of farm
manure (as urease source)
 30% moisture by adding water
 Putting this mixture in a bag, piling the
straw on the bag, again moistening the
straw with water (50% of straw)

14.  Incubating this material for a month
under the cover of plastic sheet or mud
plaster.

15. Difference from conventional
method
Three steps are eliminated
 preparation of urea solution
 sprinkling of solution on straw
 pressing the straw during treatment
process
Result in labour saving upto 55%
However, efficiency is 30% less than the
conventional urea treatment method

16. Preparation of urea treated straw

17. Urea treatment : Advantages
 It acts in just the same way on the
vegetal matter as if anhydrous ammonia
is used:
– dissolving the parietal carbohydrates
(mainly the hemicelluloses)
– swelling the vegetal matter in an aqueous
environment, so easing access by the
rumen's cellulolytic microorganisms

18. – reducing the physical strength of the cells,
so easing mastication by the animal and
digestion by the microbes,
– enriching the forage in nitrogen, as is also
the case if anhydrous ammonia is used.

19. Key success factors for urea
treatment
 Practical conditions affecting successful
treatment include the:
– presence of urease
– application rate of urea
– moisture content
– ambient temperature
– the length of the treatment period
– the degree of hermetic sealing achieved
during the treatment
– the quality of the wheat straw to be treated

20. THANKS