Environmental Impact of Cow Milk Production in the Central Italian Alps Using Life Cycle Assessment

Figures & data

Figure 1. Diagram of the flows considered in the study.

Figure 2. Percentage contribution to the main impact categories of the processes considered in the life cycle of milk.

Table 1. Selected impact categories, contributing elements and characterization factors.

Impact category	Contributing elements	Characterization factors	References
Land use, m^2	Land occupation	1	Guinée et al., 2002
Energy use, MJ	Energy consumption	1
Climate change, g CO2-eq	CO2	1	IPCC, 2007
	CH4	25
	N2O	298
Acidification, g SO2-eq	SO2	1	Hejiungs et al., 1992
	NH3	1.88
	NOx	0.7
Eutrophication, g NO3^–-eq	NOx	1.35	Hejiungs et al., 1992
	P2O5	14.09
	NH3	3.64
	NO3^–	1
	PO^3–4	10.45
	NH4^+	3.6

Table 2. Main literature references for Life Cycle impacts.

	Interviews
Farm animal rations
Origin of feeds	Eurostat, 2006, Istat, 2006.
Methane emissions	ERICA (Provolo, 2005) for cows; ISPRA (2008) for heifers. Estermann et al. (2001) during highland grazing.
Nitrogen excretion	ERICA (Provolo, 2005) for cows; EMEP/EEA (2009) for heifers; Cornell-Penn-Miner (2004) during highland grazing.
Ammonia emissions	ERICA (Provolo, 2005) for cows; EMEP/EEA (2009) for heifers and during highland grazing.
Nitrous oxide emissions	ERICA (Provolo, 2005) for cows, EMEP/EEA (2009) for heifers. IPCC (2006) during highland grazing.
On-farm
Ammonia emissions	Manure spreading: ERICA (Provolo, 2005). Artificial fertilizers: EMEP/CORINAIR (2002).
Nitrous oxide emissions	Manure spreading: ERICA (Provolo, 2005). Artificial fertilizers: IPCC (2006).
Leaching	Nitrates: Grignani and Zavattaro (2000) for grassland; Audsley (2000) for maize. Phosphates: Nemecek and Kägi (2007).
Off-farm
Ammonia emissions	Manure spreading: Thomassen et al. (2008). Artificial fertilizers: EMEP/CORINAIR (2002).
Nitrous oxide emissions	Manure and artificial fertilizers spreading: IPCC (2006).
Leaching	Nitrates: IPCC (2006) or Italian literature. Phosphates: Nemecek and Kägi (2007).

Table 3. Effect of milk production level on environmental impacts per 1 kg of Fat Protein Corrected Milk (Least Squares means).

	Milk yield per cow
	Low^°, n=8	Medium^°, n=12	High^°, n=8	SEM
Milk yield, kg/cow	3976^c	5411^b	7295^a	253
Land use total, m^2	4.98^a	2.94^b	1.82^b	0.68
on-farm	3.79^a	1.64^b	0.77^b	0.68
off-farm	1.19	1.31	1.05	0.11
Energy use total, MJ	6.21	4.97	4.98	0.84
on-farm	3.93^a	2.03^b	2.68^ab	0.78
off-farm	2.27	2.95	2.30	0.34
Climate change total, g CO2-eq	1333^a	1142^ab	967^b	99.9
on-farm	763^a	563^b	486^b	64.5
off-farm	569	580	481	58.2
Acidification total, g SO2-eq	23.3	22.9	19.8	1.96
on-farm	12.9	10.9	12.0	1.47
off-farm	10.3^ab	11.9^a	7.7^b	1.40
Eutrophication total, g NO3^–-eq	69.7	78.6	75.9	6.79
on-farm	29.0	28.6	37.7	4.94
off-farm	40.6	50.0	38.2	4.99
Gross margin, €/cow	1789^b	1903^b	2432^a	171

°Low milk yield: <4700 kg/cow; medium milk yield: 4700-6400 kg/cow; high milk yield: >6400 kg/cow.

^a,bWithin the row mean values followed by different letters are significantly different (P<0.05).

Table 4. Effect of stocking rate on environmental impacts per 1 kg of Fat Protein Corrected Milk (Least Squares means)

	Stocking rate
	Low^°, n=10	Medium^°, n=9	High^°, n=9	SEM
Stocking rate, cows/ha	1.83^c	2.64^b	3.85^a	0.24
Land use total, m^2	3.41	3.52	2.82	0.64
on-farm	2.14	2.57	1.49	0.64
off-farm	1.27^a	0.95^b	1.33^a	0.10
Energy use total, MJ	4.78	5.51	5.87	0.79
on-farm	2.05	3.48	3.11	0.73
off-farm	2.73	2.03	2.76	0.31
Climate change total, g CO2-eq	1071	1142	1229	92.8
on-farm	521	652	639	59.8
off-farm	550	490	590	54.0
Acidification total, g SO2-eq	18.7^b	22.4^ab	24.9^a	1.82
on-farm	7.5^b	14.8^a	13.6^a	1.37
off-farm	11.2^a	7.6^b	11.3^a	1.30
Eutrophication total, g NO3^–-eq	66.2^b	74.7^ab	83.4^a	6.30
on-farm	19.7^b	40.1^a	35.7^a	4.58
off-farm	46.5^ab	34.6^b	47.7^a	4.62
Gross margin, €/cow	2019	2223	1883	159

°Low stocking rate: <2.3 cows/ha; medium stocking rate: 2.3-3.3 cows/ha; high stocking rate: >3.3 cows/ha.

^a,bWithin the row mean values followed by different letters are significantly different (P<0.05).

Table 5. Effect of feed self-sufficiency on environmental impacts per 1 kg of Fat Protein Corrected Milk (Least Squares means).

	Feed self-sufficiency
	Low^°, n=10	Medium^°, n=9	High^°, n=9	SEM
Feed self-sufficiency, % DM consumed	46.8^c	62.7^b	82.0^a	2.67
Land use total, m^2	3.77	3.12	2.85	0.61
on-farm	2.34	1.89	1.98	0.62
off-farm	1.44^a	1.24^a	0.88^b	0.10
Energy use total, MJ	5.18	4.84	6.14	0.76
on-farm	2.22^b	2.33^b	4.10^a	0.70
off-farm	2.96^a	2.51^ab	2.05^b	0.30
Climate change total, g CO^2-eq	1226	1048	1167	89.7
on-farm	619	521	672	57.8
off-farm	607	527	495	52.2
Acidification total, g SO^2-eq	25.4^a	19.5^b	21.1^ab	1.76
on-farm	12.1^ab	9.5^b	14.4^a	1.32
off-farm	13.3^a	10.0^b	6.8^c	1.26
Eutrophication total, g NO3^–-eq	83.2	69.0	72.1	6.09
on-farm	29.0^ab	26.4^b	40.0^a	4.43
off-farm	54.2^a	42.6^b	32.0^b	4.47
Gross margin, €/cow	1915	2045	2165	153

°Low feed self-sufficiency: <53%; medium feed self-sufficiency: 53-72%; high feed self-sufficiency: >72%. DM, dry matter.

^a,b,cWithin the row mean values followed by different letters are significantly different (P<0.05).

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