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Welcome to the second video in this 4 part series Estimating Feed Supply
We need to understand how much forage there is and
how much of that is available to livestock
We estimate the amount of unpalatable feed
leaf fall or detachment and the amount we want to leave behind
then we subtract these from the total
A standard is used to measure feedstuff
whether livestock are eating feedlot rations or pastures
This standard is the weight of dry feed
For pasture we measure in kilograms per hectare of dry matter
When we're working out
a forage budget it's about how much pasture there is
in the paddock and how much the cattle
are going to need We need to take certain things
out of the equation So, we work out the total of the yield first
and we do that by estimating
or cutting some quadrats And then we subtract the unpalatable
what is going to be detached or trampled by stock
and also we take out residual pasture so that's what we want
to be left at the end of the grazing period which might be by Christmas time
or perhaps early January
So, the first thing we need to do as part of a forage budget
is to work out actually how much pasture
we have in the paddock And we can do that by using
these photo standards and look at the photos and
roughly line them up with what's in the paddock
So, in this paddock we'd be looking across the pasture
and comparing what we can see with what we can see in the photos
In this instance, the top photo shows 1800 kilograms
per hectare of pasture and the next one shows us 2430
And, in my estimation what we can see here
is much closer to 2400
But we find that when people use the photo standards
and they haven't done any cutting that in fact they often
over estimate how much pasture is there
So, it's advisable to do some cuts to get your eye in
and then you can use the photo standards from there on
I have the equipment here the necessary equipment
to do our cuts. I've got some paper bags
a quadrat, and a set of shears You can use secateurs
if you haven't got shears But we would probably cut
3-5 quadrats in this area to work out what the pasture yield
actually is. So what I do is find something on the horizon
like a tree, and step out every 5 or 10 meters
and cut a quadrat So, I'm going to do that now
I'm going to cut a quadrat after 5 meters
So, I'll pick out that tree on the horizon over there
and we're going to go 5 places 1 2 3 4 5
Then I put the quadrat down its at the point of my toe
So I don't bias where I actually select that quadrat
If I wanted there to be a high yield I might take this quadrat
and on the 5th step go - there's a nice big tussock
we'll choose that one but we can't do that
We want it to be an honest reflection of what's in the paddock
So now we have the quadrat placed down
We need to put into the quadrat the grass that's actually attached
and shooting up from in the base of the plant from the in quadrat itself
Everything that's in the quadrat right down to the ground level
So within about 1-2 cms at ground level
And what we're taking here is all the plant material that's
attached to a living plant base That includes all this dead material
but we'll take that out later on Some of this passing material
you can see is very old and it's going to be quite unpalatable
we'll take that out of the equation later on Put it in the paper bag
So, having cut the pasture we need to weigh it
to work what the dry amount of content is
So we need scales these are just ordinary
kitchen scales so you can steal them
from the kitchen at home They just need to weigh
to about 1-2 grams to do that And the first thing I need to do
is to actually tare the scales to the bag weight so we're not
including the bag
the weight of the pasture as well So, we tare that off
and then we weigh the pasture the bag with pasture in it
and write that down So in this case, it weighs 102 grams
Now don't forget that what we have here
is pasture that still has moisture in it We need to dry that later on
and get an estimate of what the dry matter content
of the pasture is And here is a little key for you
to work that out in the paddock I can estimate, roughly
what the dry matter content of this pasture is
by comparing it with hay Hay is about 85% dry matter
and what we've got in the paddock here is probably ready to bail
That would be my estimate of the dry matter content of the pasture
So, when we're working out
how much pasture is in the paddock it can be any easy and uniform pastures
like Mitchell grass pastures To do a transect, and do 3-5 cuts
along a transect at regular intervals and that will give
a pretty good indication of how much pasture
is actually in that part of the paddock But most paddocks are patchy
So they'll have some areas that have some high yielding pastures
another area with lower yielding pastures
in fact some areas that cattle can't access
because of distance to water or perhaps its a jump up
cattle can't go there or can't access it anyway
and other areas of the paddock that are lower yielding
So, we need to take that into account in our estimation of how much pasture
is actually in the paddock And we use an accessible yield
calculator to work that out So, in this part of the paddock
we're going to need another couple of cuts
to give us an idea of what the pasture yield is here
It's much lower here it's less for them to eat
in terms of the species that are edible as well
so we need to bring that into play as well Whereas, over here
on the higher ground we've got Mitchell grass country
and the pasture yield is much higher So we need to work out
what proportion of the paddock has low yielding pastures
what proportion of the paddock has high yielding pastures
and what proportion of the paddock cattle can't access
In our estimation of pasture yield we can take browse into account too
In the dry season when pasture quality is particularly low
cattle and sheep and goats in particular will graze a lot of browse
There will be a lot of proportion of browse in their diet
Things like blue bush we have here are highly digestible
high protein and quite valuable components
of the diet. So we can take those
into account as well And the way we would do that
is to actually increase the estimate of the palatable pasture by another 10%
Mulga is another example of a browse species
and we do the same there But we got things like lignum over here
they're actually not selected for so we don't take them into account
So once we've got that
we've also got to take into account the unpalatable stuff
So, the first thing is that carry-over material from the previous season's growth
that's gone grey
they're never going to graze that its this stuff down here
All that grey material It looks a bit like litter
that we have down here Stock aren't going to eat that
so, we need to take that out of the equation as well
and estimate what proportion of the pasture is made up of that
old grey and unpalatable material The other things
we need to take into account are unpalatable species
such as Feathertop wire grass They seldom graze Feathertop
Wire grass is in other parts of the state they seldom graze
so we need to get a handle on that too So, what proportion of this paddock
or this area is made up of wire grass? What proportion of the yield?
And my assessment here is there's not much
so it's only going to be about 5% in this case
In many other cases, it can be as high if you go into spinifex country
Unpalatable can be as high as 75% or even more
So, that definitely needs to be taken into account
So, the next thing we need
to take into account is detachment So that's the pasture material
that either falls off during the dryer months
or is trampled by cattle Usually, we work on 15% detachment
When there are a lot of annuals that might go a lot higher
If you have intensive rotational grazing systems
detachment can get up to as high as 30-40%
Now, when you have a lot of annual species
Flinders grass is a good example There's going to be
a greater amount of detachment The issue we have with annual grasses
like Flinders grass is that once they get to this stage
they're easily knocked to the ground They disintegrate during the winter
and we can end up before spring time without any grass at all
on the ground for the cattle But once they get to this stage
they're seeded and they're basically dying
The quality drops off markedly cattle won't select them as much
as they'll select green out of the pasture
We take detachment out of available feed in a forage budget
because with stock moving though it there's shattering
and trampling of the feed So it's not available for stock to use
including sheep Particularly with Flinders grass
when it comes to the months of August and September high winds
can actually shatter the grass as well and it blows it away
That's why our perennial grasses are so important
Things like Mitchell grass and blue grasses
they're the ones we need to maintain to help our stock
get through the winters with plenty of feed available
Now we need
that residual pasture there to act as ground cover
so when we get our first summer storms
we\'re going to have plenty of ground cover
and not lose all our soil In most pastures
we need to have a minimum of about 1,000-1,200 kilos
per hectare of residual to prevent erosion
So, looking at this pasture you can see that some of it
had been grazed And that's the sort of ground cover
that we'd be wanting to have In Mitchell grass country
we want a minimum of 30-40% ground cover
In other parts of Queensland some of the sloping country
might require 60-70% ground cover to ensure that there's no run-off
Estimating the forage supply requires a few simple steps to
get it right. First, you estimate
the total pasture in the paddock using photos as a guide
or cutting and weighing samples Then, you subtract what cattle
won't be able to eat the unpalatable plants
and what will be lost as detachment over
the time the stock will be grazing Finally you subtract the amount
that you want left behind to protect the soil
allow the pasture to quickly respond to rain
and for the next round of grazing
Watch the other videos in this series to learn about
estimating livestock demand and calculating a feed budget