Grazing
Gazette
penn:
|SS College of Agricultural Sciences
in cooperation with USOA/ARB
USING COMPUTER
MODELS
TO HELP IN FARM
PLANNING, DECISION
MAKING
Rabi H. Mohtar
and
Dennis R. Buckmaster
Agricultural and Biological
Engineering Department
Penn State
Computer models serve as pow
erful tools to simulate complex
systems for the purpose of under
standing the linkages and interre
lations of the components of the
system. These models offer the
power to understand, analyze, and
optimize these systems where
traditional experimental tools fail.
During the last decade, ready
access to computing power has
increased, bringing a bigger need
and practical use for these models.
Grazing systems are naturally
cross-disciplinary; with these sys
tems, soil, crop, animal, and
machines affect each other in
ways that can significanly affect
profitability. Such a system is a
typical example of a complex set
of linkages that cannot be fully
understood without the help of a
model. These models, in general,
are referred to as decision support
systems (DSS), since they can
help the user make more intelli
gent decisions through better
information.
A typical example of such DSS
is the comprehensive grazing
model (GRASIM) that link all
components of the pasture system.
GRASIM was developed at Penn
State to obtain a better under
standing of the pasture system and
determine management strategies
that yield more efficient utiliza
tion of pastures. It can generate
information suitable for estimat
ing the financial and environmen
tal consequences of alternative
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THREE MODELS TO CHOOSE
1. PORTABLE 2. STATIONARY 3.3 POINT HITCH
Berkelman’s Welding
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(519) 765-4230
dairy management strategies
including partial mechanical
harvest in the context of the year
round feed needs of the dairy herd.
In addition, the model can evalu
ate the effect of stocking rate on
needed supplementation and
amount of harvested feed.
GRASIM simulates intensive
rotational graz'ng systems by
accounting for carbon, nitrogen
and water budgets in the pasture
environment. GRASIM requires
input data regarding soils, plants,
animals, and management.
Among other things, the model
predicts soil water level, soil nitro
gen level, accumulated grazed
intake, harvested yield, and nitro
gen leaching. GRASIM simulates
four components (grass growth,
soil water, soil nitrogen, harvest/
grazing) with a daily time step. It
models multiple paddocks that
share the same soil and weather
information but can have a diffe
rent grass species.
GRASIM is still under develop
ment; funding permitting, it will
be outfitted with a user interface
making it useful to farmers and
farm advisors. The scenarios that
could be evaluated by the model
are widespread. Current plans are
to make the model capable of
addressing these questions:
■ How much stored (supple
mental) forage is needed with var
ying stocking rate on the graze
able land?
• How much can nitrogen fertil
izer application to grass pastures
help to economically increase
herd size?
• How much forage will need to
be harvested during spring growth
and how does this vary among
years and with soil type?
• Should I plant more or less
com? ,
• Am I better off with SO cows
each producing 21,000 lb milk/
year or 60 cows each producing
17,000 lb milk/year?
GRASIM will not solve all the
world’s problems, but certainly
will help agronomists, nutrition
ists. economists, and engineers
pool their knowledge in a way
which traditional experimentation
has fallen short.
Development of GRASIM has
been a collaborative effort among
the Penn State Departments of
Agriculture and Biological Engi
neering, Agronomy, Dairy and
Animal Science, and Agricultural
Economics and Rural Sociology.
Development has been financially
supported by USDA Special
Research Grants and the Pennsyl
vania Agricultural Experiment
Station.
Lmcßßltr Firming, Saturday, February 24, 1996-A23
Computer
(Continued from Pago A 23)
The Quick Bamsheet program
and Wcstfalia Dairy Plan are not
intended to be a replacement for
DHIA mainframe computing.
Component analysis date can only
be added into the reports after die
samples have been tested in the
lab.
Through partnerships of these
two programs the dairymen may
received action lists (pregnancy
COW LACTATION BRED
NAME GP L# AI FRESH DATE DAYS BULL DUE STAT
782 0 4 4 6/24 11/26/93 340 8H2205 9/2/94 Dry
849 0 3 2 7/10 12/8/93 328 9H1360 9/14/94 Pre(
794 0 4 8 2/7 1/13/94 292 8H2106 10/20/94 Dry
421 0 1 2 9/17 1/18/94 287 9H1360 10/25/94 Preg
705 0 5 4 7/11 1/19/94 286 9H1361 10/26/94 Dry
993 0 2 1 11/15 1/28/94 277 9H1289 11/4/94 Dry
851 0 3 2 10/18 1/29/94 276 9H138"’. 11/5/94 Dry
943 0 2 1 10/21 1/30/94 275 9H128) 11/6/94 Dry
407 0 I 1 11/17 2/2/94 272 9H1289 11/9/94 Dry
894 0 3 3 9/28 2/2/94 273 9H1289 11/9/94 Dty
875 0 3 2 10/15 2/3/94 271 BHI3SI 11/10/94 Dry
921 0 2 3 7/28 2/11/94 263 9H1360 11/18/94 Dry
792 0 4 3 10/9 2/15/94 259 8H2347 11/22/94 Dry
752 0 5 1 10/7 2/19/94 255 8H2106 11/26/94 Dty
999 0 1 3 9/18 2/22/94 252 9H1360 11/29/94 Dty
COWS TO CHECK FOR PREGNANCY
INSEMINATED
cow
CALVING
NAME STATUS DATE
501 Bred 4/18/94
411 Bred 10/12/94
940 Bred 7/5/94
494 Bred 2/15/94
892 Bred 2/10/94
452 Bred 2/15/94
712 Bred 1/26/94
480 Bred 7/1/96
975 Bred 2/27/94
995 Bred 3/17/94
461 Bred 5/3/94
500 Bred 4/17/94
936 Bred 5/1/94
473 Bred 6/21/94
485 Bred 3/9/94
COM NAHC
1351 809
1443 303
1389 864
1413 301
1419 302
1438 310
1518 996
1266 715
1398 869
1510 991
1296 733
1914 406
1465 939
1447 916
1450 920
1347 445
1519 410
1297 744
1394 032
1582 500
1478 958
1577 456
1457 922
1574 839
1410 897
1529 411
1527 989
1477 936
1437 306
1309 732
15 c 5 519
Committee
checks, dry dates, etc.) and rank
ings by test day milk for regroup
ing cows. Using these programs
gives the dairyman an advantage
in making quick accurate
decisions.
Please feel free to contact Pa.
DfflA at 1-800-344-8378, if we
can assist with your dairy
operation.
Examples of Westfalia Dairy
Plan reports include the following:
COWS DUE TO CALVE
EXPECTED
DATE BULL DAYS DUE DATE
9/19/94 9H1057 43 6/26/95
9/21/94 9H1289 41 6/28/95
9/23/94 8H2205 39 6/30/95
9/24/94 8H1986 38 7/1/95
9/26/94 8H2347 36 7/3/95
9/27/94 8H1986 35 7/4/95
9/28/94 8H1968 34 7/5/95
9/28/94 8H22Q5 34 7/5/95
9/30/94 9H1360 32 7/7/95
10/2/94 9H1289 30 7/9.95
10/2/94 9H1293 50 7/9 95
10/4/94 8H2459 28 7/11/95
10/4/94 8H2459 28 7/1195
10/7/94 9H1057 25 7/14/95
10/7/94 9H1293 25 7/14/95
IY TEST
LAST TEST
FAT PROT SCC
2.20 2.90 1
3.90 2.80 3
3.60 2.80 2
4.40 3.00 2
2.90 3.10 I
3.40 2.90 16
3.50 3. OO 6
4.20 3.30 3
4.60 3.30 1
3.20 2.90 1
4.10 3.30 2
4.20 2.60 5
5.10 3.90 3
3.60 3.20 1
3.80 3.50 2
0.10 2.30 3
3.90 3.b0 8
3.50 3.10 3
3.50 3.50 2
4 40 3.30 11
3.40 6
3 90 3 qO I
3.50 3 oO 6
3.90 3 10 3
3.60 3 40 5
4.20 3-20 5
4.00 2.°0 1
2.60 3 10 1
<so 3 50 3
3.60 3 20 o
PREY
54.4
82.7
80.0
91.4
87.7
99. S
79.2
0.0
58.0
77.7
63.4
ss.o
72.3
90.6
30.6
79.0
109.2
61.6
76,5
48.0
90.7
77 1
35.1
4 %
- -O 3 CO
CALVING
INTERVAL
434
624
360
SOI
508
504
525
369
495
479
432
450
436
388
492