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The break of season is a
crucial time for many ewe
flocks on annual pastures as
the quality and quantity of
dry feed is very low and the
emerging green feed will
usually need to be
supplemented to meet animal
energy requirements. Pasture
is growing very quickly and
growth rates can change over
night due to soil moisture
and temperature.
It is also important that the
amount of pasture available
is estimated
correctly as emerging
annual pasture can be
deceptive in its quantity.
Refer to the pasture
photos in the tools
for managment section to
check your estimates.
The feed intake levels form
pastures at this time is
higher than for the same
amount of pasture in the
spring time. This is
due to the upright nature
and the ease of access to
the sheep. Once clover
pastures are tightly grazed
in winter and spring it will
require at least double to
amount of FOO to maintain a
sheep.
The general steps for feed
budgeting at any time of the
year are;
1.
What they can eat - What
they require = surplus
or deficit of
energy
2.
If they aren't getting
enough energy then how
much to feed to meet the
requirement.
It is important to remember
too, that the energy
requirements of sheep vary
with the feed they are
eating, the amount of
grazing they are doing to
find the feed and their
current status of nutrition
and whether they are dry,
pregnant or lactating.
The tables presented below
are general values
only. It is important
that these are used only as
a guide and that regular
condition scoring of the
flock is the best way to
tell if the feeding rates
are adequate for their
needs.
Step 1. What they Need
Using either Table 1a. or 1b.
select the column for the
frame size and row for the
pregnancy status of the
flock, finding the value for
maintenance energy required
in MJ/day.
These values will vary
slightly depending on the
quality of paddock feed
and supplement the ewes are
eating as well as the
weather conditions and
terrain of the paddock and
the age of the
ewe (this table assumes
ewes have an average diet of
12MJ/h/d and are on sloping
terrain with 20% sub clover
in the pasture. For
other situations please
refer to Grazfeed).
Example: medium frame ewes at
condition score 3 with twins
at day 100 of pregnancy need
approximately 11.5
MJ/day to maintain their
condition.
Step 2. What
they can eat
Using Table 2 a, b or c
identify the estimated
metabolisable energy (MJ)
intake from GREEN
paddock feed. Use
Table 2a for small frame
merinos and Table 2b for
medium frame merinos and
Table 2c for large fram
merinos. Please note
that these intake figures
will change for spring
pastures or those in the
vegetative phase (see
pasture assessment for more
details).
Example: The ewes in
step 1. are grazing pastures
of green 500
FOO(kgDM/ha). This
means they can eat
approximately 9.5
MJ/day.
Step 3. Losing or Gaining
Weight?
This is calculated by
subtracting the results of
Step 1 from the results of
Step 2, that is, what they
can eat minus what they
need. This is then either a
surplus and ewes will
increase in condition,
or a deficit and ewes will
lose condition. Table 3
shows the deficit or surplus
in terms of grams per
head per day and in change
in condition score in 30
days for each frame size.
Example: The ewes from
Step 1 (need 11.5MJ/d) and
Step 2 (can eat 9.5
MJ/d) have a deficit
of 2MJ/d (11.5
-9.5MJ). This means
the ewes will be
losing about 70gms per
head per day or 0.3 of a
condition score over a
month. This is close to the
recommended weight loss
allowed for pregnant ewes
until day 90. At day
100 it is recommended that
the ewes be gaining on green
feed. This would
require at least 900 FOO
with 1500 FOO by lambing
(see guidelines
for WA and SA).
Step 4 How much
to feed?
Use the Table below
(from Managing Sheep in Dry
Times Bulletin
DAFWA) to obtain an
estimate of the energy value
of the feed expected to be
fed. We suggest that
feeds are tested as
they can
be variable, especially
hays and silage.
Step 5: Determine how much
feed to offer
Once a target condition for
the ewe flock and how much
energy is required to meet
that target been decided,
and the energy value of the
feedstuff determined you
need to calculate how much
feed to offer.
Ewes in energy deficit:
Use the table below: use the
1st column to identify the
quality of the feed (13
MJ/kg), read across until
the approximate deficit
amount is found (2MJ), then
follow the column upwards to
read off the feeding rate
(0.2kg).
OR
Divide the
deficit (MJ/day) by the
energy value of the feed
(MJ/kg). This gives
the number of kilograms per
day to be fed.
For example if ewes need
2MJ/d. Using barley at
13MJ/kg they require 2/13 =
0.154kg of barley
These figures are expressed
in dry matter per kilogram
so it is important to
convert the amount to 'as
fed' kilograms which takes
into account the moisture
content of the feed.
To do this;
Divide the kg/head/day
to be fed by the dry matter
% from Table 4. This
is the weight to be fed out
in the paddock.
For example,
barley at 90% Dry Matter and
0.100kg/hd/d
required:
0.154kg / 0.90 =
0.170kg to be fed.
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