• dairy sheep
• environmental impact
• life cycle assessment
• Tuscany

The projected rise in global population to 9.7 billion by 2050 is expected to drive a 21% increase in animal protein demand, highlighting the need for a sustainable, resource-efficient livestock sector. Currently, livestock production contributes substantially to environmental challenges: it accounts for 12% of anthropogenic greenhouse gas emissions, significant nitrogen pollution, water usage, and occupies a large share of agricultural land, impacting on biodiversity and ecosystems. Sheep farming, although lower in environmental impact than other livestock species, provides essential socio-economic benefits, especially in rural areas.
Life Cycle Assessment (LCA) is nowadays considered the best framework for assessing the potential environmental impacts of products and it is increasingly used for estimating and comparing the environmental impacts of livestock farms. However, the literature shows that LCA studies applied to the sheep sector are fewer compared to those on other livestock species. Moreover, most LCA studies conducted on the sheep production focus on the environmental impact of meat, while those investigating the milk are fewer.
This doctoral thesis aims to fill this gap by conducting a detailed LCA on the Tuscany dairy sheep sector. Tuscany is therefore one of the most significant regions for sheep farming in Italy, with a strong emphasis on dairy production that is a cornerstone of rural economy and play a vital role in the cultural and agricultural heritage of the region. By focusing on the environmental impacts of twenty dairy sheep farms in Tuscany, this study aims to quantify the impacts, identify the most significant contributors and suggest potential areas for improvement to guide sustainable practices.
Farms were selected to be as representative as possible of the dairy sheep sector of the Tuscany region. The LCA was carried out according to the ISO 14040-44 standards and the FAO’s LEAP guidelines for small ruminant supply chains. The system boundary was “from cradle to farm gate” and adopting 1 kg of fat and protein corrected milk as functional unit, twelve impact categories were evaluated along with six impacts on ecosystem services related to land use and soil carbon sequestration. Primary data corresponding to the cropping season 2021/2022 were collected on-site from a survey to the farmers, while secondary data were taken from Ecoinvent 3.9.1 database. Environmental impacts were calculated using the Environmental Footprint (EF 3.1) method and the OpenLCA software (1.11 version).
Furthermore, the study explored potential links between gastrointestinal parasite infections and the environmental sustainability of the dairy sheep farms analysed by evaluating the presence, frequency, and types of gastrointestinal parasites and using nitrogen and phosphorus excreted in animal faces as indicators of the environmental impact of dairy sheep farming.
Results confirmed the prevalence of gastrointestinal parasites, especially strongyles and coccidia, on sheep farms. Importantly, this study uncovered a significant relationship between Eimeria spp. infections and nutrient emissions, suggesting these parasites influence environmental impact by increasing nitrogen and phosphorus excretion. For instance, phosphorus emissions were higher in younger sheep, while nitrogen was higher in lactating ewes, contributing to nutrient pollution and underscoring the environmental implications of managing parasite infections on dairy sheep farms.
The life cycle analysis showed that animal and manure emissions, and crop production were the primary hotspots of sheep milk production. Environmental performances significantly varied according to flock size, rearing system, productivity and feed efficiency, showing a clear trade-off between efficiency and environmental impacts. Larger and less extensive farming systems tended to be more productive and efficient, resulting in lower environmental impacts; however, they also showed a decrease in soil carbon sequestration (Cseq). Including Cseq in the climate change impact category calculation resulted in a significant 10% reduction in the estimated impact. This underscores the importance of including Cseq in LCA studies of grazing farms to avoid overestimating their carbon footprint.
Probably due to the high level of feed self-sufficiency of all the sampled farms, this parameter did not appear to be a significant factor in reducing overall environmental impacts. On the other hand, productivity was confirmed as an important factor in reducing impacts, but stronger correlations were found between feed efficiencies and the measured impact categories. This highlights that feed efficiency, particularly protein efficiency, is a key determinant of the environmental performance of dairy sheep farming. Mitigation strategies should focus on investing in this area, optimizing feed formulations, maximizing nutrient uptake and minimizing waste and emissions.
From the results emerged an effect of the breed reared on the environmental performance of farms. The Lacaune, a French breed, stood out for its high productivity and feed efficiency, which contribute to lower environmental impacts, despite its higher resource usage and emissions. In contrast, the Sarda, a native Italian breed, exhibits similar impact scores to the Lacaune but with lower resource consumption and fewer emissions.
Overall, this study provides a comprehensive assessment of the environmental impacts associated with dairy sheep farming in Tuscany and highlights key factors, such as feed efficiency, breed selection, and parasite management, that influence sustainability. The findings underscore the importance of optimizing feed efficiency and considering soil carbon sequestration in LCA studies to accurately reflect the carbon footprint of grazing systems. Based on these results, future research should investigate a better categorization of different types of rearing systems and breeds, as well as their specific environmental profiles, exploring a larger sample of farms. By identifying critical environmental hotspots and the role of gastrointestinal parasite management, this research offers valuable insights for developing sustainable practices to reduce environmental impacts of dairy sheep farming.