# The Carcass (growth of beef cattle) model with energy as input

### Description

**Model description.** This model is proposed by
Hoch et. al (2004) to represent the growth of cattle and
the relative body composition of diferent types of
animals depending on nuritionnal conditions. It simulates
the dynamics of changes in the composition of the body
fat and proteins according to nutrient intake. The system
is represented by four state variables: the protein and
fat in the carcass (resp. ProtC and LIPC) and other
tissues (resp. ProtNC and LipNC) grouped under the name
of the fifth district (again, gastrointestinal tract,
skin .. .). These variables depend on time, the time step
used is dt = 1 day. The model is defined by 20 equations,
with a total of 18 parameters for the described process.

### Usage

1 2 3 | ```
carcass.EMI.model(protcmax, protncmax, alphac, alphanc,
gammac, gammanc, lip0, lipc1, lipnc1, beta, delta, amW,
b0c, b1c, b0nc, b1nc, c0, c1, energie, PVi, duration)
``` |

### Arguments

`protcmax` |
: amounts of protein in the carcass of the adult animal (kg) |

`protncmax` |
: amounts of protein in the 5th district of the adult animal (kg) |

`alphac` |
: maximum protein synthesis rate in the frame (excluding basal metabolism) (j-1) |

`alphanc` |
: maximum rate of protein synthesis in the 5th district (except basal metabolism) (j-1) |

`gammac` |
: Maximum rate of protein degradation in the frame (excluding basal metabolism) (j-1) |

`gammanc` |
: maximum rate of protein degradation in the 5th district (except basal metabolism) (j-1) |

`lip0` |
: maximum lipid concentration to the theoretical physiological age (percent) |

`lipc1` |
: increase coefficient of the maximum lipid concentration with the physiological age of the carcase (percent) |

`lipnc1` |
: increase coefficient of the highest lipid concentration with physiological age area in the 5th (percent) |

`beta` |
: lipid synthesis rate (j-1) |

`delta` |
: lipid degradation rate (d-1) |

`amW` |
: |

`b0c` |
: coefficient of the allometric equation linking mass and lipid-protein carcass |

`b1c` |
: exponent allometric equation linking mass and defatted protein carcass |

`b0nc` |
: coefficient of the allometric equation linking mass and lipid-protein 5th district |

`b1nc` |
: exponent allometric equation linking mass and lipid-protein 5th district |

`c0` |
: coefficient of the allometric equation between live weight and live weight empty |

`c1` |
: exponent allometric equation linking body weight and live weight empty |

`energie` |
: Metabolizable energy available |

`PVi` |
: initial liveweight |

`duration` |
: duration of simulation |

### Value

matrix with ProtC,LipC,ProtNC,LipNC,PV