Page 22—foraging Around, Lancaster Farming, Saturday, February 7, 1998
(Continued from Page 21)
The second easiest method is the
calculation method. In thjs method we
simply use "known” pounds per acre
inch of grazeable forage and other
“known” infomation and calculate
RHD without doing field harvests. We
often “rc-determine” pounds per acre
inch for our forages by doing a few
sample field harvests. Anyone would
be wise to do so for itself. Otherwise,
there are standardized figures avail
able to use to cheat the system. In this
case, we must measure or estimate the
average inches of grazeable forage
available per paddock. Let’s assume
our grass is bermudagrass and bahia
grass at 250 pounds per acre-inch. In
this case we must know acres and
stocking rate. (See Table 2.)
This method is easy to use, grazier
friendly and a good countercheck with
the visual readings.
Now, let’s do the same example us
ing the measured estimates method. In
this case we must hand harvest a rep
resentative sample(s) from each pad
dock. weigh it, tally the results and
factor in the livestock need. We use a
3.1-foot square frame for the sample
size (grams x 10 = lh/ac) and we cut at
the recommended residue height for
the forage in question. Again, I record
this in my notebook or on a form. In
this case, we must also know acres and
stocking rate, etc. (See Table 3.)
This method is good, but most gra
ziers are not inclined to go to such ex
tremes to gather the data. We have a
form available to help determine data
for methods 2 and 3.
Within any of these methods we can
make it complicated and factor in ad
ditional expected forage production,
livestock weight changes, differences
in pounds per acre-inch of forage de
pending on height of forage, etc. But,
in practice all of that makes little dif
ference in the practical use of the me
thods. A one-inch rain at the right time
is worlds more important. The RHD
and the ebbs and flows of it are much
more important than the minnute dif
ference shown by adding more com
plications. The average of the three
methods is 27.7 (or 28).
So, what does that mean? It means
that there is 28 days of feed available
without serious changes. A major use
of RHD is to also easily measure the
ebb and flow of forage supply.
The ebb and flow of the RHD range
does not make much sense unless we
know something about what the ex
pected RHD parameters need to be.
For example:
1. In the green, actively growing
season, there arc only 10-14 RHD
needed to have forage for the herd to
graze al the grass “as it grows.” More
would be excess and less is often a
problem indicator.
2. For summertime grazing, we
need to build to have 40-60 RHD
ahead of the herd by about June 15.
That excess gets our herd through the
summer forage slump.
*Bl,76o°°*
Frank Insinga, of Laceyville, PA, feeds his cows more forage now
with Full Time™ Forage. Even though his herd is 270 days in milk,
they are producing 80 pounds milk per day. Below is his regular
corn silage ration as well as his Full Time ™ Forage ration.
Feed Stuffs
Normal Corn Silage
Full Time™ Forage
Haylage
Hi-Moisture Shell Corn
Protein Concentrate +
Minerals & Vitamins
Dry Hay
Total Feed Cost/Day
Feed Cost Savin
Date; May 10,1997 ~
. . Forage In. Pounds Forage Available
Paddock Available ~ T
- Number Acres Per Ac. Per Acre PerPaHrWi.
1 20 2x250= 500 10,000
“ 20 3 750 15,000
] 20 1 250 5,000
4 15 Trace 0 0
5 25 6 1500 37,500
6 10 5 1250 12,500
7 40 2 500 20,000
—r-Z 16 4000 40.000
Totals/ 160 3.5 875 140,000
Averages
Table 2
3. For winter stockpile, we need
150-180 RHD to go through al winter
no-growth times. When there is less,
we can plan hay needs. There are other
correlations, too.
The 28 RHD means that there is
more forage growing than the stock
are eating. Why? Because, to graze all
grass as it grows and have no reserve
requires wily the 10 to 14 RHD. That
is exactly what we try to do in the
spring grazing of winter annual grass
pastures. If our objective is to graze all
grass as it grows; (1) we could add
more stock or (2) cut some for hay.
etc., or (3) leave the excess for later
grazing.
Normal Corn Sila
As Fed
40 Lbs.
25 Lbs.
28 Lbs.
20 Lbs.
s/Da'
How can we use RHD to determine
amount of hay to cut? First, we need
more RHD for grazing than we are us
ing. If we have 28 RHD and need only
14 RHD, then 'A of the area can be cut
for hay (28 - 14/28 = 50 percent). If
we have 28 RHD and need 21 RHD,
then we can harvest only 'A of the ex
tra forage (28 - 21/28 = 25 percent).
If the RHD were only 10 to 14 or
less and declining, that would indicate
a forthcoming deficient forage supply
and a need to adjust management. Do
we de-stock some or all? Do we pro
ject ahead to a sale date and get ready
to sell all of the cattle? The ebb and
(Turn to Page 23)
Cost/Day
$0.50
$0.50
$1.26
$3.98
$6.24
2.24
Full Time™ Forage
Cost/Da
As Fed
$1.12
75 lbs.
$0.50
25 Lbs.
$0.68
15 Lbs.
$1.45
9.75 Lbs.
$0.24
3 Lbs.
$3.99