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UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN N0£±2=«§> ^ MfTTTfTim inr i 181999 *4V <14200l L161 — O-1096 Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://www.archive.org/details/computerassisted20marc % U Ji i c u " 1 ■" o 3.11 >>-5 - c be o .fi £ 2 bo O o u.s b £ ■org be S g o U O > O «« M u.s rt a * s . h to c «2 « -9 U O r- O rt *5 °- o.s | b .>-• bo >> C •2 « 9 C oJ rt <-> >> bo be - o S £•£ '£ "o -p. c £ w « ° O u J c I- e« C C S g E c c C/) eu Diagrammatic structure of the generalized linear programming model. The size of the blocks in the figure is not intended to indicate the number of rows and columns in each section. (Fig. 2) 22 Appendix 1 and from noted farmer preferences. The objective function is calculated from the farm data and the individual farmer's expectations and is entered on cards. Each section of the matrix is described briefly as follows: 1A — This is a section of repetitive I matrices, or matrices having a diagonal of l's with O's elsewhere. The dimension of the matrices is determined by the number of fields required (up to 20). The number of matrices depends on the number of possible crops (up to 10) and the number of technological levels within and for all crops (up to 6 in one crop and 2 in each of the others). This section is potentially 20 rows by 480 columns. 2B — This section contains rows of crop production levels or yields per acre. There is one row for each crop. The rows are arranged diag- onally down through the section. This section is potentially 10 by 480. 3A — This section is a 10-element I matrix for the purpose of trans- ferring crop production to storage. 4A — This section (10 X 480) is made up of a row of l's for each crop, with the rows arranged diagonally through the section. This sec- tion handles the acreage limitation for individual crops. 5B, 6B, and 7B — These sections contain the labor requirement co- efficients for each crop and livestock type by months. Of these 32 rows, the first 12 are for the crop production period; the rest allow for live- stock feeding past the end of the model's arbitrary one-year period. 8A — This section (78 X 10) limits the amount of crops that can be stored to the available storage capacity; it acts as a means of transfer from production to storage to feed or sale. The section is made up of columns of l's for each crop arranged diagonally through the matrix. The first four crops can have storage accounted for by months to allow for withdrawals for feed or sales by months. The remaining six crops are set up on an annual storage basis. 9A, 10A, 11 A, 12A, and 13A — These sections are identical in that they contain lower-left-hand triangles filled with l's. The triangles are arranged diagonally through each section. This makes possible the with- drawal or addition by purchase of any of four crops in storage for feed to cattle or swine or for sale, all transactions being possible by months. The sections are completed with rows of l's arranged diagonally for annual transactions on the remaining six crops. 14A — This section contains 20 X 12 matrices repeated eight times to account for each of eight possible types of cattle that can be fed. Each matrix in the section contains several diagonals of l's, which account for use of lot capacity by any of 12 starting months over a period of up to 20 months for the model planning period. The number of diagonals of l's in a matrix depends on the length of time that a particular type of cattle will be on hand in the feedlot from purchase to sale. Appendix 1 23 15A — This section (29 X 96) contains a series of eight blocks of matrices, one for each type of hog production (feeders and farrowing) ; it contains diagonals of l's similar to those in section 14A, the number of diagonals again depending upon the length of time hogs will be using the facilities. 16B and 17B — These two sections (each 120 X 120) are identical; they are made up of sets of diagonals, with one diagonal for each crop and each nutrient required in cattle rations. The coefficients are the amount of a nutrient that a specific crop contributes to the ration. Each diagonal contains 12 coefficients — one for each month. 18B — This section (120 X 96) contains sets of diagonal matrices that indicate the monthly nutrient requirements of each nutrient for each of eight possible types of cattle. The number of diagonal rows in each matrix depends on the number of months the cattle are on hand. 19B and 20B — These two sections are similar to 16B and 17B in that they indicate the specific amount of the required hog nutrients con- tained in each crop. Since a larger number of nutrients must be con- sidered for hogs, these sections are each 136 X 120. 21B — This section, similar to 18B, contains the nutrient require- ments of eight possible swine types by month and by nutrient. This section is 136 X 96. In the restriction vector, 22B gives the number of acres available in each field, 24B gives the upper or lower limit allowable in acres of each possible crop, 25B gives the amount of labor available for each month, 26B gives the storage capacity available for each crop by month, 27B and 28B give the cattle and swine capacities (also by month), and 23C, 29C, and 30C are sets of 0's to force internal matrix transfers. Appendix 2: The Matrix Generator and Report Generator As previously explained, the purpose of the matrix-generator/ report-generator system is to simplify input and solution interpre- tation and thereby reduce the costs of using linear programming for individual-farm planning. The generators developed are of the "model-specific" type, with no capability for handling matrix structures not previously defined in the general model. In a research environment, this is somewhat inconvenient because it precludes the use of the generator system to test alternate model structures. The approach is, however, satisfactory for a com- mercial application in which the basic model structure remains un- changed for long periods. In order to structure an individual-farm model, the matrix generator requires parameters to specify what alternatives will be considered and what non-unit coefficients will be entered in matrix locations. The parameters and individual- farm coefficients (constraints, costs and prices, labor requirements, yields) are read from cards. The secondary data are extracted from arrays embedded in the matrix-generator code, as are the unit coefficients. All unit coefficients associated with a particular activity are auto- matically entered into the appropriate matrix locations when a param- eter specifies that activity as an alternative to be considered. For example, if Crop One grown in Field One is to be considered as a production alternative, l's will be generated in the Field One acreage restriction rows and in the Crop One acreage restriction rows. All other necessary unit coefficients are generated similarly. The appropriate secondary data arrays are automatically entered into the correct locations of the matrix when called for by a param- eter string. The data generated in this manner are the various nutrient levels supplied by both homegrown and purchased feeds and the vari- ous nutrient requirements of livestock being fed at a particular rate. These coefficients are assumed to be approximately the same from farm to farm. It is assumed, for example, that every bushel of No. 2 yellow corn produced anywhere in Champaign County provides the same amount of digestible protein, total digestible nutrients, calcium, etc. when used for feed. Or again, a 500-pound steer being fed to gain 1.5 pounds per day is assumed to require the same level of protein, calcium, phosphorus, etc. per day regardless of the farm on which it is fed; if this assumption is not acceptable, secondary data can be subclassified as below average, average, and above average to reflect differences in feeding efficiency due to management or some other factor. 24 Appendix 2 25 Different types of individual- farm data, such as all constraint values, objective function values, yields, labor requirements, etc., are input to the matrix generator on different types of cards. 1 The placement of values on these various card types determines where the particular values will be placed in the matrix. Values in certain locations on partic- ular card types require other cards to be present in the data deck. These other cards are used to enter the remaining coefficients for a particular activity or constraint. For example, if card 0002 specifies that corn grown in Field One is to be considered as a production alternative, then the matrix generator anticipates a labor requirement card, a yield card, an objective function value card, a disposal activity card (whether the crop is to be sold, fed, or both), an acreage restriction card, and a storage restriction card. The program rejects a farm's data whenever required cards are absent or illicit card codes are entered. Card type descriptions. The card type identifiers are punched in columns 1 to 5. A discussion of three card types will illustrate the man- ner in which data are input into the matrix generator. '0002' — Grown Crop Description Card. This is a mandatory card since it indicates which crops are to be considered as production al- ternatives. A maximum of 10 crops may be considered. Columns 6-55 Format: 10(12, 12, II). For each crop considered as grown, three values are necessarily input in the three fields provided. Field No. 1: The identification number of the crop to be grown is entered in this field; for example, "21" indicates that lespedeza hay is to be considered as an alternative, and "01" indicates that corn is to be considered. All possible crop growing activities for Illinois have been assigned code numbers. Field No. 2: The nature of the crop usage is entered here. "07" indicates that the crop to be grown can be either sold or fed to live- stock (both cattle and hogs). Silage, "01," can be grown and fed only to cattle. Soybeans, "08," can only be grown and sold. The current generalized model employs 16 such usage codes. Field No. 3: This field is used to indicate if there is an acreage restriction on the crop. A here indicates no acreage restriction; 1 means there is an acreage restriction in the amount indicated by the right-hand value in the appropriate acreage restriction row. If corn is to be considered as Crop One, columns 6 through 10 on the '0002' card could be coded "01071." This would indicate that the corn produced could be either sold or fed to cattle and hogs. Accord- ingly, corn selling, corn fed to cattle, and corn fed to hogs activities 1 The card type is designated by the particular code found in columns 1 through 5. For example, 0100's are crop labor requirement cards, 0200's are crop yield cards, 6000's are RHS value cards, etc. 26 Appendix 2 would be generated and the appropriate unit coefficients placed in the matrix. A restriction on corn acreage is also indicated (perhaps the farmer plans to follow the Feed Grains Program). Similar information for Crop Two is entered in columns 11 through 15, for Crop Three in columns 16 through 20, and so on. This card and the '0003' card (the Purchased Crop Description Card) specify the cropping activities to be considered on a particular farm. The position on these two cards (that is, the particular set of five columns) identifies whether the crop is Crop One, Two, . . . , Ten and whether the feed is Feed One, Two, . . . , Ten. Thereafter, the price data, yield data, etc. entered for particular crops or feeds are identified by crop number. '01CCL' — Crop Growing Labor Card. This is a mandatory card for each crop specified on the '0002' card. A separate card is needed for each crop and for each level. Columns 6-65 Format: 12F5.0. 'CC = ("01" through "10"). This is the crop number as it appears in the matrix (Crop One, etc.). 'JJ = ("0" implies "1"). This indicates the level for which the labor coeffi- cients apply. The crop's monthly labor technical coefficients per acre are entered here in each field. For example, on a card coded 01040, .46 in columns 21 through 25 indicates that Crop Four at Level One re- quires .46 hours of labor per acre in April (columns 6 through 10 are for January, 11 through 15 for February, etc.). '0400' — Cattle Raising Description Cards. This card is optional and is required only if cattle feeding is considered as a production alternative. This card generates correct monthly nutrient requirements. Columns 6-69 Format: 8(11, 12, 12, 3X). Three fields must be com- pleted for each cattle type considered. A maximum of eight cattle types can be considered at any one time. Field No. 1: Expected growth rate identification (1 = 1.0 lbs. per day; 2 = 1.5 lbs. per day; 3 = 1.75 lbs. per day; 4 = 2.00 lbs. per day ; 5 = 2.25 lbs. per day; and 6 = 2.5 lbs. per day) . Field No. 2: The starting weight identification number is entered here. It is calculated as follows: 0j . -1-j Starting weight — 400 lbs. , , Starting weight l.d. no. = —=— — ^ r- 5 rpr^ + 1 Rate of gam per 10 days For example, animals started at 700 pounds and gaining 2.0 pounds per day have a starting weight identification number of 16. 700 - 400 20 + 1 = 16 Field No. 3: The number of months for which the particular cattle type is to be fed is given here. Appendix 2 27 For example, 0400 40909 indicates that type 1 cattle are expected to gain two pounds per day, started at 560 pounds, and sold nine months later. These three values collectively determine the appropriate monthly nutrient requirements for this size animal to attain the rate of gain specified. These nutrient requirements, their coefficients being drawn from secondary data, are then generated in the appropriate matrix lo- cations during matrix generation. The report generator, activated by the successful solution of the problem by MPS/360, accepts the MPS solution and interprets it for output in a format such as that shown for the sample problem in Ap- pendix 3. The report generator also computes the total receipts and costs shown on the report, but its main function is to format the output. Appendix 3: An Example of a Crop Production Run FARM CHARACTERISTICS The farm used as an example of the planning method is located on gently rolling land in Champaign County, Illinois. The dominant crops are corn and soybeans ; livestock enterprises consist of feeder cattle and hogs, both farrowed and fed. The farm is operated by the tenant and his son, both on a full-time basis. Past production records indicate that the operators are above average in management ability. Their planning objective is maximization of net profit within the constraints of their subjective desires and existing facilities and equipment. The available resources and the production alternatives to be con- sidered are discussed in the following sections. Land. The farm comprises 871 tillable acres divided into 10 fields. The total area is rented from one landlord on a 50-50 crop-livestock lease. The field acreages are shown in Table 3. Buildings. The existing buildings are important in that they limit the types and sizes of livestock and crop storage alternatives to be con- sidered. The cattle feeding facilities of this farm are a barn of 160- head capacity and a silo system capable of storing 700 tons of silage. Farrowing facilities can accommodate 36 sows and litters (averaging 8.5 pigs per litter) simultaneously, and the hog finishing facilities can accommodate 600 head. Total on- farm grain storage capacity is 62,000 bushels, all of which is used for corn. In the past any beans grown have been stored in town. Labor. The labor of the two operators is to be supplemented by a full-time hired man in early 1971. Therefore, three full-time equivalents will be available except during vacations, taken during slack periods. The manhours of available labor during the period covered by the crop production plan are shown in Table 4. The 32 months of labor are shown to accommodate the 12 months (October 1969 to September 1970) of the crop production period, the Table 3. — Field Acreages Field Acreage Field Acreage 1 121 6 70 2 50 7 112 3 101 8 112 4 51 9 105 5 119 10 30 28 Appendix 3 29 Table 4. — Labor Avail f ab/e per Month Month Man- Month Man- Month Man- hours hours hours October 1969 475 August 1970 587 June 1971 792 November 1969 462 September 1970 537 July 1971 792 December 1969 384 October 1970 648 August 1971 792 January 1970 384 November 1970 648 September 1971 720 February 1970 386 December 1970 576 October 1971 648 March 1970 455 January 1971 576 November 1971 648 April 1970 531 February 1971 576 December 1971 576 May 1970 604 March 1971 648 January 1972 576 June 1970 606 April 1971 720 February 1972 576 July 1970 589 May 1971 792 March 1972 April 1972 May 1972 648 720 792 12 months during which these crops are disposed of (October 1970 to September 1971), and an additional eight months to allow feeder live- stock to be introduced during the later part of the disposal period. This long extra period of time must be included to account for all live- stock alternatives, but any plans for longer than 12 months are neces- sarily tentative and are updated at subsequent runs. Capital. Shortrun operating capital is not an effectively limiting resource on this farm. The owner has alternative sources of operating capital at the going interest rate. There are definitely long term capital limitations, but since we are concerned only with the immediate pro- duction period, these limitations can safely be ignored. Machinery. Enough equipment is available to operate the farm under any feasible cropping system. Thus, machinery is not a limiting resource for the crop and livestock alternatives under consideration. Table 5 gives a summary of the physical constraints for the farm. The objective is to select the combination of activities that will maxi- mize the return from these limited resources over the coming production period. The next step is therefore to determine which alternative activi- ties are to be considered. The operator is consulted here so that only enterprises he will consider are involved. As a start, his present plan and his past records are reviewed. Crop alternatives. The farm has been planted primarily in corn, for grain and silage, and in soybeans, with a small acreage of wheat. These crops are the enterprises to be considered as production alternatives in this crop production run. Livestock alternatives. In each of the three years, the operator has fed 100 to 200 head of cattle and sold up to 1,200 hogs. Some of the hogs sold are farrowed on the farm. Feeder cattle, feeder pigs, and hog farrowing are therefore the admissible livestock alternatives. 30 Appendix 3 Table 5. — Names of Production Constraints Acres in fields 1 to 10 Labor available in months 1 to 32 Storage capacity for corn in months 13 to 24 Storage capacity for silage in months 13 to 24 Cattle f eedlot capacity in months 13 to 24 Swine farrowing capacity in months 13 to 24 Swine finishing capacity in months 13 to 24 D.M. requirements for cattle in months 13 to 24 T.D.N, requirements for cattle in months 13 to 24 D.P. requirements for cattle in months 13 to 24 Ca requirements for cattle in months 13 to 24 P requirements for cattle in months 13 to 24 Urea requirements for cattle in months 13 to 24 Crude fiber requirements for swine in months 13 to 24 T.D.N, requirements for swine in months 13 to 24 Crude protein requirements for swine in months 13 to 24 Ca requirements for swine in months 13 to 24 P requirements for swine in months 13 to 24 Lysine requirements for swine in months 13 to 24 Methionine requirements for swine in months 13 to 24 Tryptophan requirements for swine in months 13 to 24 After determining the possible crop and livestock production al- ternatives, numerous other activity choices are implied: What levels of crops and types of livestock should be considered, 1 in which fields can various crops be grown, in what months can these crops be sold, what livestock feeds are to be considered, and in what months can these feeds be purchased ? The alternative activities for the farm in this example are summarized in Table 6. MODEL SPECIFICATIONS The matrix coefficients used to specify the matrix for the example are discussed in the sections below. Objective function values. The expected variable production costs per acre for each of the five crops considered were calculated using past data from the farm, with secondary data derived from cost sur- veys used as a guide. Corn and corn silage were considered at two levels of fertilization, while soybeans and wheat were considered at one level. The variable costs used in the problem are shown in Table 7. A 5-year monthly average selling price for corn, soybeans, and wheat was calculated from records made available by the local elevator ; these averages gave the expected seasonal price variation. Using Sep- 1 Production levels are defined here to be such variables as rates of fertilizer application, plant population, row spacing, etc., which affect the yield or the growing cost of the particular crop. Types are defined here to be such variables as rates of gain, buying and selling weight, length of feeding period, etc., which affect the objective function value. Appendix 3 31 Table 6. — Production Alternatives Corn at fertilizer level 1 (200-100-100) in fields 1 to 10 Corn at fertilizer level 2 (160-80-80) in fields 1 to 10 Soybeans (no fertilizer) in fields 1 to 10 Wheat (80-40-40) in fields 1 to 10 Corn silage level 1 (200-100-100) in fields 1 to 10 Corn silage level 2 (160-80-80) in fields 1 to 10 Feed grown corn to cattle in months 13 to 24 Feed grown corn to swine in months 13 to 24 Feed bought alfalfa hay to cattle in months 13 to 24 Feed bought mixed hay to cattle in months 13 to 24 Feed grown silage to cattle in months 13 to 24 Feed bought protein supplement to cattle in months 13 to 24 Feed bought oats to cattle in months 13 to 24 Feed bought oats to swine in months 13 to 24 Feed bought protein supplement to swine in months 13 to 24 Feed bought dical to swine in months 13 to 24 Feed bought lime to swine in months 13 to 24 Sell corn in months 13 to 24 Sell beans in months 13 to 24 Sell wheat in months 13 to 24 Start feeding 560 lb. steers for 9 months, at 2.00 lbs. per day, in months. ... 13 to 24 Start feeding 760 lb. steers for 7 months, at 2.00 lbs. per day, in months. ... 13 to 24 Farrow 1 litter pigs to be sold 5 months later, in months 13 to 24 Start feeding 40 lb. feeder pigs for 4 months at 1.5 lbs. per day, in months. . . 13 to 24 Dummv feeding activities for months 25 to 32 Table 7. — Expected Variable Production Costs for Crops in Dollars Corn level 1 (200-100-100) 53.25 Corn level 2 (160-80-80) 48.45 Beans 31.85 Wheat 24.12 Silage level 1 (200-100-100) 61.20 Silage level 2 (160-80-80) 56.40 tember, 1969, prices as a base and the monthly futures prices, these 5- year monthly averages were adjusted to arrive at the expected monthly selling prices for corn, soybeans, and wheat (Table 8). Xo selling prices were calculated for corn silage since the corn would be harvested as grain rather than as silage if it were unprofitable to feed silage. Storage costs were then deducted from the expected monthly selling prices and the net prices were the ones actually used for each crop. Expected monthly purchase prices for the various feeds (Table 9) were also estimated by using local elevator 1969 feed prices and the selling prices previously determined (for feeds also grown). Objective function values for all livestock activities were estimated using the futures market, the selling prices in Chicago for the past five years, and detailed selling prices and purchase costs from the individual farm's 1969 records. (These prices were all for the relevant grades being considered on the farm.) Using the September, 1969, buying and selling 32 Appendix 3 Table 8. — Expected Monthly Selling Prices in Dollars Per Bushel Month Corn Wheat Soybeans October 1.06 November 1.07 December 1 . 10 January 1.11 February 1 . 13 March 1.15 April 1.16 May 1.18 June 1.17 July 1.15 August 1.13 September 1 . 09 1.20 2.25 1.22 2.26 1.23 2.28 1.24 2.31 1.25 2.33 1.26 2.35 1.28 2.37 1.30 2.39 1.27 2.40 1.24 2.39 1.18 2.38 1.19 2.34 Table 9. — Expected Monthly Feed Purchase Prices in Dollars Month Corn Alfalfa hay Oats Protein 42% hog supple- ment Mixed hay Lime Dical Protein 40% cattle supple- ment (bu.) (cwt.) (bu.) (cwt.) (cwt.) (cwt.) (cwt.) (cwt.) October 1.09 1.40 .67 6.90 1.15 2.10 6.90 5.80 November 1.11 1.45 .68 6.90 1.17 2.10 6.90 5.80 December 1.13 1.47 .69 6.90 1.18 2.10 6.90 5.80 January 1.15 1.49 .72 6.90 1.20 2.10 6.90 5.80 February 1.17 1.51 .75 6.90 1.21 2.10 6.90 5.80 March 1.19 1.53 .77 6.90 1.22 2.10 6.90 5.80 April 1.21 1.56 .76 6.90 1.24 2.10 6.90 5.80 May 1.23 1.49 .75 6.90 1.27 2.10 6.90 5.80 June 1.24 1.46 .71 6.90 1.19 2.10 6.90 5.80 July 1.22 1.43 .68 6.90 1.13 2.10 6.90 5.80 August 1.18 1.41 .69 6.90 1.15 2.10 6.90 5.80 September 1.12 1.38 .70 6.90 1.17 2.10 6.90 5.80 prices as base prices, and using the futures prices, the 5-year monthly price averages were adjusted to arrive at the expected buying and sell- ing prices (Tables 10 and 11). Total purchase cost and variable produc- tion expenses, except labor and feed (Table 12), were deducted from the total sales value to obtain the objective function coefficient for each type in each month. The objective function values for farrowing were calculated by deducting variable production costs per litter, except feed and labor, from the expected sales value per litter. An average of 8.5 pigs per litter was assumed to be sold from each litter farrowed. Thus, the sales value per litter is 8.5 times the expected selling value. Technical coefficients. Monthly labor requirements for enterprises were not available from the farm's records. Therefore, these coefficients Appendix 3 33 Table 10. — Expected Cattle Buying and Selling Prices (Dollars Per 100 Lbs.) Type I: Steers 1 Dought at 560 lbs. Type II : Steers bought at 760 lbs. and sold 9 mon ths later at 1,100 and sold 7 mon iths later at 1,180 lbs. — 2.0 lbs. daily rate of gain lbs. — 2.0 lbs. daily rate of gain Purchase Pur- chase price Selling Selling Purchase Pur- chase price Selling Selling month month price month month price October 33.00 July 27.79 October 33.00 April 27.75 November 32.00 August 28.18 November 32.00 May 27.30 December 31.00 September 28.33 December 31.00 June 27.40 January 30.00 October 29.00 January 30.00 July 27.79 February 30.25 November 28.50 February 30.25 August 28.18 March 30.70 December 27.75 March 30.70 September 28.33 April 30.15 January 27.00 April 30.15 October 29 . 00 May 30.80 February 27.20 May 30.80 November 28.50 June 30.85 March 27.66 June 30.85 December 27.75 July 31.00 April 27.66 July 31.00 January 27.00 August 31.40 May 27.64 August 31.40 February 27.20 September 31.50 June 27.68 September • 31.50 March 27.66 Table 77. — Expected Hog Buying and Selling Prices (Dollars Per 700 Lbs.) Purchase Pur- chase price Selling Selling Farrowing Selling Selling month month price month month price October 21.40 February 20.10 October March 20.40 November 21.55 March 20.40 November April 21.80 December 21.90 April 21.80 December May 22.10 January 22.30 May 22.10 January June 22.60 February 22.65 June 22.60 Februarv July 22.85 March 23.00 July 22.85 March August 22.10 April 22.80 August 22.10 April September 21.60 May 22.40 September 21.60 May October 21.00 June 21.70 October 21.00 June November 20.85 July 21.40 November 20.85 July December 20.40 August 20.90 December 20.40 August January 20.00 September 20.30 January 20.00 September February 22.20 Table 12. — Expected Non-Labor, Non-Feed, Variable Production Costs for Livestock (in Dollars) Type Expected production cost Type I cattle (per head) 5 . 44 Type II cattle (per head) 5 .44 Farrowing (per litter) 26 . 96 Feeder hogs (per head) 4.86 34 Appendix 3 Table 13. — Expected Crop Labor Requirements Per Acre and Per Month (Man-hours) Month Corn Soybeans Wheat Silage October. . . November. December. January. . . February. . March April May June July August . . . September October. . . November. December. 57 14 07 14 32 33 15 32 52 46 10 52 36 69 25 36 .28 62 56 28 17 13 15 1 40 26 65 6 75 76 20 14 40 Table 14. — Livestock Labor Requirements Per Head Per Month (Man-hours)* Tvpe I Tvpe II *- Feeder Month cattle cattle F^™* hogs (per head) (per head) lper lltter; (per head) Month 1 23 .23 3.5 .26 Month 2 36 .36 2.1 .26 Month 3 42 .42 2.1 .26 Month4 42 .42 2.1 .26 Month 5 38 .38 2.1 Month 6 43 .43 2.1 Month 7 39 .39 Month 8 38 .38 Month 9 36 .36 Month 10 53 .53 Month 11 55 .55 Month 12 38 .38 a Month 1, for cattle, is October; month 1, for farrowing, is the month in which farrowing takes place. The requirements for feeder hogs are the same in each month. were estimated using secondary data derived from labor use surveys. For each crop, data were available by month according to equipment size. Tractor horsepower and equipment sizes were recorded during the farm interview to determine correct labor coefficients (Table 13). Monthly labor coefficients for livestock (Table 14) were also de- termined from secondary data. These secondary coefficients were avail- able according to feeding setup (pasture versus confinement, slotted floors versus solid floors, etc.) and degree of feeding automation, de- termined during the interview. The monthly cattle labor coefficients were determined primarily by seasonal conditions regardless of the starting month. For example, the per head labor requirement for October would be the same for a partial- Appendix 3 35 Field number Table 15. — Expected Crop Yields Per Acre by Field Corn (level 1) Corn (level 2) Soy- beans Wheat Corn silage (level 1) Corn silage (level 2) bu. 1 140 2 132 3 129 4 130 5 136 6 126 7 124 8 123 9 120 10 141 bu. bu. bu. cwt. cwt. 135 34 59 395 380 128 33 57 370 360 125 32.5 58 362 350 126 29 51 365 353 130 30.5 49 373 365 121 27 46 340 332 118 25 44 332 324 119 28.5 41 336 326 116 27 41 329 320 136 34 58 396 382 lar animal whether that is the first, fourth, or ninth month the animal has been on feed. The swine labor coefficients, on the other hand, were assumed to be the same in the starting month regardless of the particu- lar month. The same is true for months two through six for farrowing. The expected yields derived for the various crops in each of the fields (Table 15) were based on past records for the farm. On this particular farm, field maps showing fertilizer applications and crop yields were available for each field for each of the last three years. The nutrient provisions of various grown and purchased feeds and the various monthly nutrient requirements for livestock were estimated entirely from secondary data. 2 Individual farm data are not available for these coefficients. These represent all the data necessary to program this particular farm using the relevant subset of the general model. RESULTS Report No. I (see pages 38-39) Report No. I, the production plan, contains physical information specific to each enterprise. The production plan is composed of four sections: (1) crop production; (2) cattle production; (3) swine pro- duction ; and (4) livestock feeding plan. Section I — crop production. In the first part of this section the total acreage, average yield, and total production are given for each 2 See, for example, G. P. Lofgreen, "Digestible Protein, Total Digestible Nutrients, and Net Energy Requirements for Maintenance and Gain of Beef Cattle," Uni- versity of California Department of Animal Science ; Frank Morrison, Feeds and Feeding, Morrison Publishing Company, Clinton, Iowa, 22nd ed., 1959; and D. E. Becker, A. H. Jensen, and B. G. Harmon, "Balancing Swine Rations," University of Illinois College of Agriculture, Circular 866. 36 Appendix 3 crop. The second part of this section provides a production recommen- dation by enterprise and field. In addition, the technological (fertilizer) level, the expected yield, the acres in each field to be utilized by a par- ticular crop, and the expected variable growing cost are indicated. For example, line 7 indicates that 86 acres of corn at Level One (200-100- 100; lbs. N-P-K) should be grown in Field One with an expected yield of 140 bushels per acre. The expected variable production costs for Field One are $53.25 per acre. Section II — cattle production. This section provides information on each lot of feeder cattle that is recommended for purchase. The description of each lot is, in order, buying weight, length of feeding period, final weight, optimal rate of gain per day, month bought and sold, number of head, pounds of beef produced, return per head, pur- chase price, and sale price per 100 pounds. All purchases are recorded in this section whether the feeders are to be sold during the immediate 12-month period or are to be in ending inventory at the end of this period. The pounds produced during the 12-month period for each lot is recorded for all animals. The values given in the expected return column are the respective objective function values. These values, for example $128.00 in line 19, are calculated by deducting the purchase price and variable production expenses from the selling price per head. Section III — swine production. A specific description of each lot of pigs farrowed or fed, if called for in the optimal solution, is given here. These data include length of feeding period, expected average litter size, purchase weight for feeders, selling weight, month farrowed, number of litters farrowed, pounds produced, expected return, and pur- chase and sale prices. This information is interpreted as in the cattle section. In this specific case, only feeder pigs are recommended. Section IV — livestock feed plan. This section provides a monthly feeding plan for both cattle and hogs. For purchased feeds, the ex- pected monthly purchase price and the quantity to be purchased (num- ber of bushels or hundredweights) are given. For grown feeds only the quantity to be fed is given. Report No. II (see page 40) Report No. II, the budget, contains a financial summary of expected receipts and expenses for the planning period. It is composed of three sections: (1) receipts and expenses for crops; (2) receipts and ex- penses for cattle; and (3) receipts and expenses for swine. Section I — crop receipts and expenses. Each crop sale is listed sepa- rately, giving the crop name, the selling month, the selling price, the number of units sold, and the total receipts of each sale. There may be more than one sale listed for each crop, as there is for corn in this example. On this farm, more corn is planned for production than can Appendix 3 37 be stored on the farm. Therefore, the production in excess of storage capacity is sold at harvest at $1.06. The remainder is fed to livestock or sold in' May at $1.18. The total value of crops sold ($112,292) is the summation of all crop sales. In order to get an accurate valuation for crops grown, crops fed must be valued at the price at which they could be sold. Thus, the value placed on crops fed is the expected selling price in the respective feeding month, not the growing cost. The summation of the crop sales and crops fed accounts is the total crop value. Variable production expenses for all crops are deducted from the total crop value to get the expected return above direct cost for grain ($76,171). Section II — cattle receipts and expenses. Each cattle sale, during the 12-month period being programmed, is recorded by type. This in- cludes all animals in inventory at the start of the period and all lots bought and sold during the period. Lots that are purchased but not sold during the period are not entered on this report. (They are recorded on Report No. I, however.) For example, line 16 indicates that 160 steers weighing 560 pounds are bought, fed for nine months, and sold at ap- proximately 1,100 pounds. The optimal daily rate of gain was deter- mined to be two pounds. The objective function value per head times 160 gives the sales value of $20,480. The total cattle feed expense (grown and purchased) is deducted from the total sales figures to ar- rive at the expected return above direct production costs for cattle ($11,297). Section III — swine receipts and expenses. Receipts and expenses in this section are calculated like those for cattle and are interpreted in the same way. Following the swine section, an expected return above direct production cost for the entire farm ($104,389) is calcu- lated by summing the return figures of Sections I through III. SUMMARY The reports presented as an example are imperfect in several areas. First, the format is not entirely satisfactory and needs to be consider- ably altered to make the reports useful for real-world users. Second, the values shown in the reports are subject to roundoff errors ; hence, there appear to be disagreements between some of the computed num- bers (which are, however, accurate). Third, the "expected net profit" is computed as the return above variable costs and is not comparable with the usual definition of net profit, which takes into account fixed costs and depreciation. Fourth, the "inventory change" entry on Report II shows a zero value because this facility has not yet been activated. Despite its present shortcomings, however, the system discussed in this report shows great promise and may lead to a system usable in commercial applications of farm planning. 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