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heat increment
which is the most important parameter we
are looking for is then equal to total
heat production
minus fast angle production so
if we include this uh hip
increment value as hip production minus
fasting reproduction
in our previous diagram you can
obtain the net energy value which is
equivalent
now to m e minus f production
plus fasting reproduction then if you
consider that
amy minus field production is equal to
energy gain or energy retention you then
get the net energy
equivalent to energy gain or energy
retention
plus fasting reproduction being keeping
in mind
that energy gain can be growth of an
animal
in broilers or in growing pigs for
instance but it can be also
exporting energy as milk in the
sow or eggs as in
laying ends so the ratio between net
energy
and me is called k or the efficiency of
me for net energy
this k value if we look for
a rather constant or rather basic or
conventional diets
is very similar in all or four
types of animals we are dealing with on
that figure
so about 25 of dme is lost as heat
increment
which means that the efficiency or the
average efficiency
for conventional diet for all these
animal species is about 75
so we could think that the efficiency is
rather constant
but it's not constant it changed a lot
and it changed because
you have behind the emi uh different
nutrients
which are used very differently for net
energy
i have taken the values obtained in pigs
but we could get the same data
in poetry indicating that the energy
coming from
protein is used with an efficiency that
is about 60
while the energy coming from starch or
from fat
are used with efficiency much higher 80
or 90
so this means that the net energy over
me ratio will not be constant
for diets and also more importantly for
ingredients
since this efficiency will vary with the
nutrients composition of the diet or the
ingredient
and so that's the main purpose or the
main objective
of these videos is to look at the
impact of changing the nutrients
composition
of diets or of ingredients on the net
energy value of feeds
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