Environmental impact of dairy buffalo heifers kept on pasture or in confinement

In western countries buffaloes are emerging as an alternative species for dairy product differentiation. In the near future dairy enterprises will have to meet increasing environmental regulations. Life Cycle Assessment has been widely used to assess the environmental impact of different milk production systems. We aimed to examine the environmental consequences of two dairy buffalo heifer farming systems using the Life Cycle Assessment approach. The primary data were collected from 32 subjects aged 7–8 months at the start of the experiment until they reached the age of puberty in about 12 months (i.e. at the age of 19–20 months). Sixteen animals were group-housed and confined in an indoor slatted floor pen (4 m2/animal) with an outdoor paddock (4 m2/animal); 16 others free-ranged on a Mediterranean natural pasture. The environmental charges for global warming potential expressed in terms of total emissions of carbon dioxide equivalent (CO2-eq) was 35.7% less in the free-ranging system as compared with the confined system. The main source of pollution for the confined system was biogenic methane (total amount produced = 2012 kg CO2-eq) followed by CO2from fossil fuels (total amount produced = 1006 kg CO2-eq). The environmental charges for acidification potential, eutrophication potential and non-renewable energy use were 86.3%. 60.0% and 81.4% lower in the free-ranging system compared with the confined system, respectively. In the confined system the largest pollutant in terms of acidification potential was ammonia, whereas nitrate leaching in water (total amount produced = 3311 g SO2-eq) and the use of crude oil (total amount consumed = 5684 MJ-eq) were the most relevant for eutrophication potential and non-renewable energy use, respectively. Our results represent the first example of study comparing the environmental impact of an intensive dairy farming system with an alternative natural pasture based system in the Mediterranean region and suggest that the conduction of the unproductive part of the cycle on natural pasture can promote the reduction of several sources of pollution both in atmosphere and in water. Conversely, land occupation was higher in the free-ranging system as compared with the confined system (20,349 vs 1381 m2year, respectively). However, the software and the database used for this calculation only considered duration of land use and yield per area unit, whereas no relevance was given to the quality of land use in terms of animal welfare promotion, contribution to biodiversity conservation, and maintenance of economically active social communities. Therefore, we suggest that the estimation of the impact categories related to land occupation would include aspects concerning the nature of the land.