Results

The sensitivity of comparative milk footprints from dairy farm systems implementing conventional and legume-based animal diets to choice of allocation method was accessed by analysing and comparing carbon footprints generated through the use of Feedprint NL and AgRe Calc using both mass and economic allocation methods, different dairy cow diets and different genetic merits.

It was found that mass and economic allocation methods, different dairy cow diets and different genetic merits can create very varied footprints. Table 7.1 to 7.4 show the averages for each of the cow groups. It can be seen in these tables that across all of the groups mass allocation generated a higher footprint then economic allocation. And it can be seen that the select cows had higher milk yield then the control cows and in turn a lower Milk EF (kg CO₂-eq/L).

1.1      By product diet averages

	Economic BPC Average	Mass BPC Average	Economic BPS Average	Mass BPS Average
System kg CO2-eq	508989.3	2085834	568506.5	2331630.25
Milk prod (L)	433420.5	433420.5	545373.5	545373.5
Milk EF (kg CO2-eq/L)	1.18	4.83	1.04	4.28

*BPC = By product diet control,   BPS = By product diet select

1.2      High forge diet averages

	Economic HFC Average	Mass HFC Average	Economic HFS Average	Mass HFS Average
System kg CO2-eq	529911.6	758624	504,980	654251.4
Milk prod (L)	405650.4	405650.4	433,361	433361
Milk EF (kg CO2-eq/L)	1.31	1.87	1.17	1.52

*HFC = High forge diet control,   HFS = High forge diet select

1.3      Low forge diet averages

	Economic LFC Average	Mass LFC Average	Economic LFS Average	Mass LFS Average
System kg CO2-eq	497483	735,624	486775	691597.2
Milk prod (L)	479329.2	479,329	533950.2	533950.2
Milk EF (kg CO2-eq/L)	1.04	1.53	0.91	1.30

*LFC = Low forge diet control,   LFS = Low forge diet select

1.4      Home grown diet averages

	Economic HGC Average	Mass HFC Average	Economic HGS Average	Mass HGS Average
System kg CO2-eq	430,483	840,371	474,597	910,055
Milk prod (L)	356,441	356,441	424,024	424,024
Milk EF (kg CO2-eq/L)	1.21	2.36	1.13	2.18

*HGC = Home grown diet control,   HGS = Home grown diet select

The bar chart in Figure 7.1 shows all the cow groups together and their average EF per litre of milk (kg CO₂-eq/L). It can be seen that across all of the groups mass allocation generated a higher footprint then economic allocation. And it can be seen that the select cows had higher milk yield then the control cows and in turn a lower Milk EF (kg CO₂-eq/L).

The box plot in Figure 7.2 shows all the cow groups together and their average EF per litre of milk (kg CO₂-eq/L). It can be seen that across all of the groups mass allocation generated a higher footprint then economic allocation. And it can be seen that the select cows had higher milk yield then the control cows and in turn a lower Milk EF (kg CO₂-eq/L). This also shows the averages for each of the cow groups.

It can be concluded that the use of mass and economic allocation methods, the different dairy cow diets and the different genetic merits can have substantial variance on footprints for dairy farms.