Programmable Calculators and Their Application to Feeding and

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					Programmable Calculators and Their Application to
Feeding and Management of Dairy Cattle 1
                                                                                  J. G. LINN 2 and P. L. SPIKE
                                                                                          Iowa State University
                                                                                                  Ames 50011

                    ABSTRACT                                   PROG R A M M A B L E C A L C U L A T O R S

      The programmable calculator offers                    Handheld programmable calculators can
   high-speed numerical analyses at a rela-             perform all the functions of less sophisticated
   tively low cost. Laborious and compli-               calculators and also store variables in memories
   cated calculations in ration formulation             for use in prewritten programs. The programs
   and other dairy-management decisions                 are a series of instructions or mathematical
   can be simplified greatly. Most dairy                equations which the programmable calculator
   producers, however, have neither the time            can remember and then execute in the desired
   nor background for developing calculator             sequence. The programmable calculator is
   programs. The Iowa State University                  similar to larger computers in that it can be
   Cooperative Extension Service has devel-             programmed to decide which series of calcula-
   oped a subscription service to supply                tions should be performed first. The decision-
   programs to persons involved in agri-                making process generally is centered around the
   cultural decisions. Also, the solid-state            calculator's capability to determine differences
   module has been developed to store                   in the relative magnitude of two numbers
   programs permanently inside the calcu-               (i.e., Is X greater than Y?). Thus, different
   lator. The programmable calculator offers            calculations can be performed, depending
   an aid in the day-to-day management                  upon     previous calculations or informa-
   decisions by agricultural producers, but             tion.
   extension personnel also find it time-                   Programs for the programmable calculators
   saving and a useful educational tool.                are not written in a computer language but
                                                        represent the key sequence needed to perform
                  INTRODUCTION                          the same calculations on a nonprogrammable
   During the last decade, handheld calculators         calculator. Once a program has been entered
have developed from a simple adding machine             into the calculator's memory, a series of cal-
into a sophisticated tool for complex numerical         culations can be repeated an indefinite number
calculations. A recent development is the               o f times by using new variables. Also, some
programmable calculator. This paper will                programmable calculators have the capability of
describe what programmable calculators are,             recording programs or data on magnetic cards
discuss their advantages and disadvantages, and         for future use. The Texas Instrument model 59
explain how the Iowa State University Coop-             and the Hewlett Packard model 973 are two
erative Extension Service has applied the Texas         calculators capable of storing programs on
Instrument Model 593 to feeding and managing            magnetic cards. Thus, the often long and
dairy cattle.                                           tedious procedure of entering program steps
                                                        before each use is eliminated. Programs can be
                                                        recorded from the calculator by passing a
                                                        magnetic card or cards through a slot in the
    Received August 20, 1979.                           programmable calculator. Once recorded, the
    xJournal Paper No. J-9567 of the Iowa Agriculture   program can be reentered into the program-
and Home Economics Experiment Station, Ames.
Project No. 1053.                                       mable calculator at any time by inserting the
    2Present address: Department of Animal Science,     card through the calculator. The capability of
University of Minnesota, St. Paul 55101.                recording programs is important because the
    SMention of a commercial product or firm is for     greatest gain in efficiency occurs when the
clarity of description only and does not constitute
endorsement by Iowa State University and cooperating    calculator can "remember" how to perform a
units or agencies nor recommendation over other pro-    long series o f calculations, thus allowing users
ducts that may be similarly suitable.                   to concentrate more on interpreting results of

1980 J Dairy Sci 63:1390-1394                      1390
                      SYMPOSIUM: COMPUTER PROGRAMS FOR DAIRY CATTLE                                 1391

outputs rather than on program entry. Also,             6. Because of relatively easy programming,
many different programs can be entered into          programmable calculator users can modify
memory with ease.                                    existing programs or develop new ones to fit
    Some programmable calculators, such as the       their own needs.
Texas Instruments TI-58 and TI-59, can use              Programmable calculators also have dis-
preprogrammed modules. These modules are             advantages that limit application:
approximately 1 cm thick and 2 cm square and            1. Limited amounts of data can be stored at
fit into the back o f the calculator. The internal   any one time. In the TI-59, memory capacity is
solid-state modules contain permanently stored       limited to 100 values or less and a maximum of
programs that are accessible directly through        960 steps in any one program.
the keyboard. One module contains approxi-               2. The programmable calculator printers
mately 5000 program instructions and, depend-        have limited alphabetical capability and do not
ing upon program length, can replace from 10         allow for extensive self-interpretable output.
to 25 magnetic cards. The module has the             Thus, printouts must either be accompanied by
advantage in that it eliminates the initial          a written explanation or transferred to a more
entering of programs. Two disadvantages are          self-explanatory form.
that module programs cannot be changed or                3. Because programmable calculators are
altered and modules must be produced in large        relatively inexpensive and may be purchased in
quantities to minimize cost.                         a variety of stores, limited assistance is available
    Most programmable calculators can print          for operation and programming. Many first
selected material. Some have a built-in printing     time users have found this very frustrating and
units whereas others, such as the TI-59, have         subsequent discouragement for future use.
optionally attachable printers. The TI-59
calculator can print alphabetical characters, but                PROGRAM DEVELOPMENT
this requires considerable program memory.                        AND IMPLEMENTATION
Printers are most benefical in writing or enter-        The development and distribution of soft-
ing programs because users can retrace entry         ware (programs) for owners of programmable
steps quickly and conveniently.                      calculators has been limited, especiaIIy for
                                                     agriculturally related programs. Some of the
     ADVANTAGES AND DISADVANTAGES                    earliest application of programmable calculators
    The programmable calculator has several          and program development in agriculture was
advantages relative to other types of computer       made by the Iowa State University Cooperative
hardware:                                            Extension Service. Previously users had to
    1. A large mathematical capacity can be          develop their own programs or rely on calcu-
obtained for a low cost ($300 or less). Simple       lator companies to supply them. As interest in
problems can be solved more conveniently and         programmable calculators grew, the need for a
at a lower cost on a programmable calculator         program exchange between extension personnel
than with large computers.                           became evident. Concurrently, as calculators
    2. Programmable calculators are completely       gained more exposure through extension
portable.                                            meetings, agribusinessmen and agricultural
    3. Programmable calculators are similar in       producers began purchasing calculators and
appearance to common handheld calculators.           identifying program needs.
Thus, the psychological barrier sometimes               The Iowa State program library is an accum-
encountered with use of full-size computers is       ulation of programs written for the T1-59
reduced.                                             programmable calculator. Agribusiness person-
    4. Programmable calculators allow for in-        nel, along with agricultural producers, have
stant turn around time with system interaction.      been instrumental in identifying areas where
They are complete units, requiring no long           programs are needed. Once a program need has
distance hookups as with portable terminals to       been identified, the program is written and
computers.                                           followed by field testing. After the program
    5. Programmable calculators can be oper-         passes testing and is approved, it is made
 ated when it is convenient and timely in any        available on a subscription basis. Subscribers
location.                                            receive a n o t e b o o k containing all previously

                                                              Journal of Dairy Science Vol. 63, No. 8, 1980
1392                                             LINN AND SPIKE

written programs and are updated with new                user operational problems.
programs as they become available. Notification              Sixty-nine percent of the survey respondents
of any existing program changes also is included.        indicated that having programs stored internally
At present, 61 programs relating to animal               in the calculator, such as with program modules,
science, farm management, and agronomy are               would help eliminate some of the problems
included in the library. Animal science pro-             encountered. Thus a Texas Instrument--Iowa
grams are primarily in the area of livestock             State University agricultural module was
nutrition, emphasis on ration formulation                developed to eliminate the reading of magnetic
and analysis, and performance indexes for beef           cards.
and swine. The farm management programs are                  Extension and agribusiness personnel along
concerned primarily with budgeting, invest-              with livestock producers identified 16 programs
ment, and livestock and crop marketing analysis.         to include in a module. The programs are pri-
More than 1300 Iowa State University libraries           marily library programs on livestock nutrition
have been distributed in 40 states and 12                (analyzing and formulating rations), analysis of
foreign countries. Cornell University also has a         livestock marketing, and land investment and
similar subscription service for programmable            general livestock management programs. During
calculator programs.                                     the first 4 too, approximately 800 modules
     Each Iowa State library program contains a          have been distributed.
statement of its objective, inputs and outputs,
 documentation of data used in calculations, and                     APPLICATIONS OF THE
 an example problem. A listing of program steps                   PROGRAMMABLE CALCULATOR
 and how the program, once entered, can be                   The programmable calculator should be
 recorded on a magnetic card for future use also         considered as a supplement to, and not a
 is included. Magnetic cards containing the              substitute for, larger computers. The calculator
 programs are not distributed because cards              can be taken directly onto the farm and used to
 recorded on one calculator cannot always be             help solve simple management problems at low
 read by another, even of the same model.                cost. Rations can be formulated and manage-
     McGrann and Edwards (1), after an early             ment decisions made for individual situations
 survey of library subscribers, described some           quickly and accurately. Many agribusiness firms
 problems encountered among 140 users of the             have found a one-on-one situation with instant
 programmable calculator (Table 1). The most             individualized answers to help improve sales.
 frequent difficulty was recording programs on               Extension personnel can use programmable
 magnetic cards and (or) the reading of cards            calculators to help solve individual management
 into the calculator. Some of the problems can           problems and as an educational tool. In con-
  be traced to mechanical failure of calculators         suiting with dairymen, ration deficiencies can
 themselves, but user program entering probably          be determined and new rations formulated in a
 was the major problem. Having an attachable             short time. Farm management programs can be
 printer for the calculator tended to reduce             used to quickly and accurately determine
 recording and use problems, especially in               individualized answers to complicated budgeting
 entering program steps and recording on                 questions. In preparing for extension meetings,
 magnetic cards.                                         the programmable calculator can be used to
     Forty-four percent of survey respondents            speed preparation of materials, particularly
 had either written new programs or modified             when a series of rations or cost analyses are to
 library programs to fit their own situations. In        be used.
  as much as writing or modifying programs                   The Iowa State dairy ration balancing
 requires more knowledge than just entering and          program was designed to answer the following
 recording prewritten programs, these users               questions in relation to the amount and quality
  tended to have less operational problems in             of forage fed: 1) What percentage of crude
  recording and using library programs than did          protein, calcium, and phosphorus is needed in
  those who only used library programs. Exper-            the grain mixture? 2) How much grain should
  ience of the Iowa State extension staff has been        be fed at various amounts of milk production?
  that a 2 to 3 h training session on calculator          3) How much protein supplementation is
  operation has been sufficient to overcome most          needed at various amounts of milk production?

 Journal of Dairy Science Vol. 63, No. 8, 1980
                       SYMPOSIUM: COMPUTER PROGRAMS FOR DAIRY CATTLE                                   1393

TABLE 1. Problems encountered with programmable calculators.

Type of problem                                                Number a                          Percenta

No. problems                                                   50                                 36
Mechanical problem, charger, or printer                        18                                 13
Incorrect results after all program steps
  entered                                                      13                                  9
Problems recording program steps on magnetic cards
  and (or) reading recorded cards into calculator              42                                 30
Interpretation problems with information
  entered or stored in calculator                              15                                 11
Problems interpreting significance of program answers          15                                 11

   aSome respondents indicated more than one problem.

Such programs can be used to help individual            grams should be a tool used in the extension
dairymen with their ration-formulation prob-            educational process.
lems and also can be used as educational aids
during meetings. For example, a dairyman may
not understand a net energy deficiency of 10                                 FUTURE
Meal for cows in early lactation. Indicating a             Programmable calculators are just one phase
requirement of 38 lb of concentrate when only           of the rapidly developing electronic technology
25 lb are fed, however, clearly illustrates an          for dairy management. Therefore, their future
energy deficiency for the cow. The effects of           is uncertain. If present use is any indication,
improving forage quality on reducing grain              acceptance of and the capabilities of program-
recommendations can quickly be shown by                 mable calculators will increase. The limiting
changing a few forage input variables. In               aspect of programmable calculator use is and
addition, audience interest is stimulated by            will continue to be program development.
the use of a new gimmick or gadget.                     Currently, most dairy programs are concerned
     The limitations relating to the instruments'       with either formulating or analyzing rations.
capability have been explained already. It must         Experiences at Iowa State with beef and swine
be remembered, however, that the program-               indicate that the most popular and widely used
mable calculator outputs are only as accurate as        programs concern economical decisions on
the inputs. If errors are made in data entry,           marketing based upon management inputs.
erroneous recommendations can be given.                 Similar programs for day-to-day management
 Likewise, if data sources for programs are not         decisions will be most useful to dairy pro-
documented, the validity of these programs              ducers. Such programs relating to economical
should be questioned. Interpretation of o u t p u t     decisions concerning cow culling, mastitis
also requires a person with knowledge and               losses, values and costs o f replacement ani-
experience in that area. As more programmable           mals, semen pricing, and many others need to
calculators come into use in ration formulations,       be developed. In addition, specific discipline
are all users going to be qualified nutritionists?      programs in areas such as engineering concern-
Not thoroughly understanding or misinterpret-           ing waste management, housing, and ventilation
ing outputs may be more harmful than the                will be of benefit to extension and agribusiness
original problem. The principal limitations of          personnel. Because of limited data storage,
 the programmable calculator as a sophisticated          programmable calculators cannot do the genetic
y e t simple tool in aiding agricultural decisions       evaluations and formulation of least-cost
occurs with the users. The education of the user        rations currently done in large computers.
to properly input information, followed by               Likewise, Dairy Herd Improvement records
 correctly interpreting and applying the outputs,       cannot be kept on programmable calculators.
 should be the primary goal for extension                Because of this, programmable calculators will
 personnel. Developing and writing new pro-              not compete with computers but will compli-

                                                                Journal of Dairy Science Vol. 63, No. 8, 1980
13 94                                           LINN AND SPIKE

ment them as a convenient low-cost analytical           preparation and individual problem consulta-
tool for field use.                                     tions. Livestock producers and agribusiness
                                                        personnel also find the calculator to be o f great
                    SUMMARY                             assistance in their day-to-day decision-making
   Experiences with the programmable calcu-             processes.
lator at Iowa State University indicate that it
has useful application in agricultural manage-
ment decisions. The calculator's low-cost                                 REFERENCES
analytical capacity, ease of programming, and
                                                         1 McGrann, J. M., and W. E. Edwards, 1979. Appli-
sufficient capacity to provide valuable informa-           cation of the programmable calculator to extension
tion for many agricultural decisions make it a             agricultural management programs. North Cent. J.
valuable tool for extension workers in meeting             Agric. Econ. (In press).

Journal of Dairy Science Vol. 63, No. 8, 1980

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