Calculate milk energy requirements (for biophysical allocation)

Calculates the energy required for milk production over the assessment period (MJ/cohort/assessment period), based on total fat- and protein-corrected milk (FPCM) produced by the cohort.

Usage

calc_milk_allocation_energy(
  milk_production_fpcm_cohort,
  milk_protein_fraction_standard,
  milk_fat_fraction_standard,
  milk_lactose_fraction_standard
)

Arguments

milk_production_fpcm_cohort: Numeric. Total fat-protein-corrected milk (FPCM) produced over the assessment period (kg/cohort/assessment period). Suggested standard fat, protein and lactose contents are 0.04, 0.033, and 0.048 respectively.
milk_protein_fraction_standard: Numeric. Standard protein content of milk, used to calculate Fat-protein-corrected milk (FPCM), (kg protein/kg milk). Suggested value = 0.033.
milk_fat_fraction_standard: Numeric. Standard fat content of milk, used to calculate Fat-protein-corrected milk (FPCM), (kg fat/kg milk). Suggested value = 0.04.
milk_lactose_fraction_standard: Numeric. Standard lactose content of milk, used to calculate Fat-protein-corrected milk (FPCM) , (kg lactose/kg milk). Suggested value = 0.048.

Value

Numeric. Energy required to produce total milk output by cohort (MJ/cohort/assessment period). Non-zero values are applicable only to milk-producing species and cohorts (species = CTL, BFL, CML, SHP, GTS; cohorts=FA). All other species–cohort combinations are assigned a value of 0.

Details

This function provides the milk-related energy term used in a biophysical allocation framework to apportion emissions between milk and other co-products in multifunctional livestock production systems.

The approach implements the IDF (2022) standard, adapted from Thoma and Nemecek (2020), and is consistent with FAO LEAP livestock LCA guidelines (FAO, 2016a, 2016b, 2016c) and with ISO 14044:2006 (Section 4.3.4.2, Step 2).

In accordance with ISO 14044:2006, known biophysical relationships may be used to assign shared inputs and outputs of a production system to individual products or sub-units. In livestock systems, this includes apportioning shared feed and energy use according to physiological energy requirements such as lactation, growth, and maintenance. If the resulting process remains multifunctional, these energy terms may subsequently be used to derive allocation factors among co-products.

The milk_allocation_energy is calculated as follows:

\(energy\_allocation\_milk = energy\_standard \times milk\_production\_fpcm\_cohort\)

where:

energy_standard is the energy content of standard milk, calculated internally based on standard fat, protein, and lactose contents following IDF (2022) (MJ/kg milk).
milk_production_fpcm_cohort is the total fat- and protein-corrected milk (FPCM) produced over the assessment period (kg/assessment period). It can be computed using calc_milk_production (see also run_production_module).

This function is part of the run_allocation_module().

References

ISO. (2006). Environmental management — Life cycle assessment — Requirements and guidelines (ISO 14044:2006). International Organization for Standardization, Geneva.

IDF. (2022). The IDF Global Carbon Footprint Standard for the Dairy Sector. Bulletin of the IDF No. 520/2022. International Dairy Federation, Brussels.

Thoma, G., and Nemecek, T. (2020). Allocation between milk and meat in dairy LCA: Critical discussion of the IDF’s standard methodology. In Proceedings of the 12th International Conference on Life Cycle Assessment of Food (LCAFood 2020) (pp. 83–89), 13–16 October, Berlin, Germany.

FAO. (2016a). Environmental performance of large ruminant supply chains: Guidelines for assessment. Livestock Environmental Assessment and Performance (LEAP) Partnership. FAO, Rome, Italy.

FAO. (2016b). Greenhouse gas emissions and fossil energy use from small ruminant supply chains: Guidelines for assessment. Livestock Environmental Assessment and Performance (LEAP) Partnership. FAO, Rome, Italy.

FAO. (2016c). Greenhouse gas emissions and fossil energy use from poultry supply chains: Guidelines for assessment. Livestock Environmental Assessment and Performance (LEAP) Partnership. FAO, Rome, Italy.