Alkali treatment of roughages and energy utilization of treated roughages fed to sheep and goats
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Date
1981
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Dar es Salaam
Abstract
Two series of experiment were conducted, laboratory scale experiments, and
and production experiments.
The laboratory scale scale experiments were carried out to develop simple
methods of alkali-treatment, and to test the- effectiveness
of cheap alternative chemicals lo sodium hydroxide.
Pro
duction experiments were conducted to tost the effectiveness
of an apparently promising "dip" treatment motheJ developed
in the laboratory scale experiments.
and k.a
Ca(CII)
The effectiveness of Na9CO3 emu
lUn,2 cis roughage
treating chemicals were tested in combination with NaOH in
a 3 x 3 factorial experiment.
The levels of the chemicals
tested were 0, 3 and 6 g/100 g of roughage (DM).
was used as a test roughage.
Wheat straw
Neither of the chemicals re-
suited in any improvement in the digestibility of the straw’
although Ca(OII)2 showed a slight effect in increasing the
enzyme soluble organic matter of wheat straw.
Both chemicals
showed a somewhat negative interaction with NaOH.
Maize stover and Hyparrhenia grass were also treated
with increasing levels of Na2COg from 0 to 10 g/100 g of
roughage DM.
Maize stover did not show any response to Na2CO3
treatment except for its enzyme soluble organic matter which
increased with increasing levels of Na2CO3.
The enzyme
soluble organic matter for the untreated maize stover was
29%, while that for maize stover treated with 10 g Na2CO-/
100 g of roughage DM was 43.6%.
Hyparrhenia grass responded
comparatively better to Na?CO3 treatment than maize stover.
Addition of herring meal to the roughages resulted in a(X)
marked improvement in the digestibility of both roughages.
This also improved the response of the roughages to ^2^0^
treatment.
Maize stover showed a higher response to the
addition of herring meal than IJyparrhenia grass.
The chemical composition of 4 samples of local Magadi
soda was determined.
All the samples had high sodium
chloride contents, indicating a possibility of Magadi soda
having a positive effect on voluntary feed intake.
It was
rioted that some samples had rather high fluorine contents.
Studies were conducted on the effectiveness of a simple
"dip" method which involved dipping straw in a 1.5% NaOH
solution overnight, letting it drip, washing with minimum
water, and letting it drip again.
The lye solution was
reused 15 times, the strength of the solution being restored
after each treatment.
The DM and Na content of the lye
solution increased with increasing reuse of the solution.
The DM content of the solution increased from 1.9% to 7.2%,
while the Na content increased from 0.7 to 1.4%.
Both the
DM and Na contents of the solution tended to stabilize after
the solution had been reused more than 10 times.
The IVOMD
and ESOM of the treated straw increased with increasing
reuse of the solution.
The in vivo DM and OM digestibility
as well as DE of the straw was improved markedly by the dip
method.
The digestibility of OM of the untreated straw was
50% as opposed to 73% for the dip treated straw.
The diges
tibility of DM and OM in vivo was not affected by the reiise
of the solution although that of CF tended to decrease
slightly after the solution had been reused more than 10 times.(Xi )
In the production experiments a comparative slaughter
technique was applied with sheep and goats.
Three groups
of goats were fed rations based on untreated maize cobs,
"dip" treated maize cobs (NaOII-treatment) , and Chlorin
gayana hay.
The experimental feeding period was 100 days.
The DM intake from these rations was the same in the three
groups, but the dip NaOII treatment of maize cobs resulted
in a higher DM digestibility (G4.1%
as opposed to
)
higher metabolizable energy intake (4.19 MJ as opposed to
3.40 MJ/d) when compared to the group fed untreated maize
The group fed dip treated maize cobs also had sig
cobs.
nifleant higher gains in liveweight, carcass weight, car-
cass fat, and carcass gross energy content.
This group,
however, did not differ significantly from the group fed
Chloris gayana hay in these parameters.
It was also observed
that, the group fed dip treated maize cobs had a tendency
to lay down intestinal fat.
Three groups of sheep were also fed on untreated maize
stover, dip treated maize stover and ensiled (NaOH-treated)
Hyparrhenia grass silage for 100 days.
centrate in the DM intake was about 20%.
The level of con
Although dip treat
ment of maize stover increased its digestibility, this did
not result in significant differences in performance between
the group fed untreated maize stover in all the parameters
studied.
The groups fed maize stover (untreated or treated)
had however significantly bettor performance in all para-
meters measured than the group fed NaOII-treated Hyparrhonxa
silage.(xii)
CorreiaLions wore determined between whole carcass fat
Z and carcass weight, and between carcass fat -i and carcass
specific gravity.
In goats, the correlation coefficient for carcass fat
Z on carcass weight was 0.84, while that between carcass
fat " and carcass specific gravity was -0.97.
These para
meters (carcass weight, and carcass specific gravity) can
there?fore probably bo used to estimate carcass fat S and
consequently carcass energy content in goats.
The correlation coefficient between carcass fats and
carcass weight in sheep was only 0.52, while that between
carcass fat S and carcass specific gravity was -0.79.
In
addition to those comparatively low relationships in sheep,
it was noted that carcass specific gravity was rather sen
sitive and difficult to measure in fat carcasses, and
liable to technical errors.
It is
thought that those
relationships cannot therefore be applied universally to
the heterogeneous sheep of East Africa.
Description
PhD Thesis
Keywords
Sheep, Goats, Energy utilization, Roughages, Alkali treatment