Environmental impact and social attributes of small- and large- scale dairy farms

In recent years a growing interest was observed from public opinion in the concept of “sustainability” of farming systems (Van Calker et al., 2005). A common perception is that a dairy farm based on pasture, with low-input and low number of cows is more respectful from the environmental point of view than an intensive and large dairy farm (Capper et al., 2009). The aim of this work is to study the environmental impact and the social attributes of intensive dairy farms characterised by different scale in terms of number of lactating cows. We selected 22 dairy farms located in the Po valley in the North of Italy. All the farms were members of the same cooperative feed industry and belonged to one of the two groups: ≤ 70 or ≥ 150 lactating cows. The environmental impact of each dairy farm was calculated with a detailed ‘‘cradle-to-farm-gate’’ LCA. All the processes related to the farm activity (i.e. forage and crop production, energy use, fuel consumption, manure and livestock management), and all external factors or inputs (i.e. production of fertilisers, pesticides, feed, energy and fuels, litter materials, replacing animals) were considered as part of the system. The functional unit chosen was 1 kg fat and protein corrected milk (FPCM, 4.0% of fat and 3.3% of protein content). LCA was carried out with SimaPro 7.3.2 (PRé Consultants bv., 2011). Gross margin, i.e. revenues minus direct production costs, excluding labour cost (€/t FPCM) was used as economic indicator. The social attributes of the farming systems were studied using an on-line questionnaire sent to a large sample of stakeholders with different age (18 to more than 60). Daily milk production, stocking density and feed selfsufficiency were not significantly different between the two group of farms; also the production efficiency and economic performance, expressed as dairy efficiency and gross margin, were similar (Table 1). Large scale farms had higher percentage of farm land sown with maize for silage, lower percentage of grassland in comparison with the other group. Nitrogen and phosphorus balances at farm level did not show any significant difference among farms. Climate change and acidification potentials per kg FPCM showed significantly lower value in the large scale farms (P < 0.05) compared with smaller ones (Table 2). The results in terms of climate change potential were in agreement with previous studies of Rotz et al. (2010); this could be due to the reduction of methane emission determined by the higher intake of maize silage and high moisture maize silage of cows in large scale farms in comparison with the other group (9.7 vs 7.7 kg DM) (Cedeberg and Flysiö, 2004). Energy use was higher in small dairy farms compared to large ones. The results of the survey (n=479) showed that common perception of some aspects of farming systems sustainability is frequently far from our data, in particular for climate change, eutrophication potential and energy use most of the people considered that large farm impact more than small ones. The results showed that intensive dairy farms with a high number of lactating cows fed with maize-based diet reduced the environmental impact of milk production particularly for greenhouse emission, energy use and land occupation compared with similar intensive farms but with lower number of cows. The study suggests that ecological sustainability is not compromised by increasing farm scale.