Holstein cows (Farm 5). For the model, the average methane reduction achieved using
60 and 80 mg 3NOP per kg dry feed in the experiment was 30% [18] was used.
The original input data of Farm 5 and modelled data for the theoretical
administration of 3NOP were evaluated. The 3NOP supplement contains 8.85%
3NOP mixed with silicon dioxide and propylene glycol [18]. The share of silicon
dioxide and propylene glycol was assumed to be 50% each. The quantity of 3NOP
added to cow feed was calculated per litre of milk: based on the average concentration of 3NOP used in the experiment (70 mg/kg dry feed) and the total feed (the
sum of maize and concentrated feed) per kilogram of milk. The input of 3NOP was
modelled as the production of organic chemicals. Emissions of hydrogen increased
64 fold due to the treatment [18] and this was included in the model (see Table 1).
The emission of hydrogen is not environmentally relevant and thus not assessed by
any impact assessment method used in this study.
Addressing animal feed production (C)
Direct emissions play a major role in the greenhouse gas emissions of raw milk. All
other impact categories are dominated by the production of concentrated feed and
the housing system [9]. Figure 2 shows the contribution analysis of milk from a
South African farm for the six impact categories.
Feed (i.e. silage maize, concentrated feed and grass) is responsible for 15–24%
of the climate impact of milk. In all other categories considered, feed dominates the
impact (see Fig. 2). Measures reducing environmental impacts from the production
of animal feed are therefore a way to decrease the life cycle impact of milk.
Table 1 Input per litre of milk at Farm 5 with feed additive 3NOP
Type of flow
Dataset
Origin
mg/kg raw milk
Input
Chemical, organic (3NOP)
Global
47
Input
Silica sand
Global
265
Input
Propylene glycol, liquid
Global
265
Output
Hydrogen emissions
–
25
0%
20%
40%
60%
80%
100%
GHG
emissions
CED
non-ren.
Freshw.
Eutr.
Marine
Eutr.
Freshw.
Ecotox.
Land
use
Direct emissions
Concentrated feed
Grass
Maize silage
Housing system
Remainder
Fig. 2 Contribution analysis of raw milk from Holstein cows at a farm in KwaZulu-Natal
analysed in our study (Farm 2) for six impact indicators
Assessment of Cleantech Options to Mitigate the Environmental …
119
60 and 80 mg 3NOP per kg dry feed in the experiment was 30% [18] was used.
The original input data of Farm 5 and modelled data for the theoretical
administration of 3NOP were evaluated. The 3NOP supplement contains 8.85%
3NOP mixed with silicon dioxide and propylene glycol [18]. The share of silicon
dioxide and propylene glycol was assumed to be 50% each. The quantity of 3NOP
added to cow feed was calculated per litre of milk: based on the average concentration of 3NOP used in the experiment (70 mg/kg dry feed) and the total feed (the
sum of maize and concentrated feed) per kilogram of milk. The input of 3NOP was
modelled as the production of organic chemicals. Emissions of hydrogen increased
64 fold due to the treatment [18] and this was included in the model (see Table 1).
The emission of hydrogen is not environmentally relevant and thus not assessed by
any impact assessment method used in this study.
Addressing animal feed production (C)
Direct emissions play a major role in the greenhouse gas emissions of raw milk. All
other impact categories are dominated by the production of concentrated feed and
the housing system [9]. Figure 2 shows the contribution analysis of milk from a
South African farm for the six impact categories.
Feed (i.e. silage maize, concentrated feed and grass) is responsible for 15–24%
of the climate impact of milk. In all other categories considered, feed dominates the
impact (see Fig. 2). Measures reducing environmental impacts from the production
of animal feed are therefore a way to decrease the life cycle impact of milk.
Table 1 Input per litre of milk at Farm 5 with feed additive 3NOP
Type of flow
Dataset
Origin
mg/kg raw milk
Input
Chemical, organic (3NOP)
Global
47
Input
Silica sand
Global
265
Input
Propylene glycol, liquid
Global
265
Output
Hydrogen emissions
–
25
0%
20%
40%
60%
80%
100%
GHG
emissions
CED
non-ren.
Freshw.
Eutr.
Marine
Eutr.
Freshw.
Ecotox.
Land
use
Direct emissions
Concentrated feed
Grass
Maize silage
Housing system
Remainder
Fig. 2 Contribution analysis of raw milk from Holstein cows at a farm in KwaZulu-Natal
analysed in our study (Farm 2) for six impact indicators
Assessment of Cleantech Options to Mitigate the Environmental …
119