Length : around 25 minutes
Write the following model using GAMS.
« An animal feed company produces concentrates for cattle using various types of ingredients : protein crops (peas), cereal (maize) and cattle cake (soya-bean).
The concentrates obtained must have a minimum guaranteed content of TNM (Total Nitrogenous Matter) and fat as well as maximum mineral matter and crude fibre contents.
| Maximum contents per kilo of concentrate | TNM (g/kg) | Fat (g/kg) | ||
| 200 | 25 | |||
| Maximum contents per kilo of concentrate | Mineral matter (g/kg) | Crude fibre (g/kg) | |||
| 70 | 65 |
The contents of each of these components are known for every ingredient.
| Contents | TNM (g/kg) | Fat (g/kg) | Mineral matter (g/kg) | Crude fibre (g/kg) |
| Maize | 81 | 37 | 12 | 22 |
| Peas | 207 | 10 | 30 | 52 |
| Soya-bean cakes | 453 | 19 | 64 | 60 |
Maize now costs 148€/T, peas 195€/T and soya-bean cakes 355€/T.
The company would like to find the optimum formulation of a kilo of concentrate in order to respect the guaranteed contents while minimizing production costs. »
For help concerning the development of the model and/or in order to use the same names for the data/variables/equations, click on “Help”.
Once the model has been written, answer the following questions : What is the optimum formulation of a kilo of concentrate ? How much does it cost ?
Click on “Solution” and check that you have the same results.
