Environmental impacts of implementing basket fans for heat abatement in dairy farms.

Health and welfare impairments in dairy cows have been described to increase environmental impacts of milk production due to their negative effect on cow productivity. One of the welfare problems is heat stress, which is gaining importance even in temperate regions. While improving animal welfare may reduce emissions, the mitigation potential depends on the environmental costs associated with specific intervention measures. Taking abatement of heat stress as an example, the aim of the present study was to estimate the effect of implementing mechanical ventilation devices on the contribution potential of milk production to global warming (GWP), terrestrial acidification (TAP) and freshwater eutrophication (FEP). Environmental impacts of two modelled production systems located in alpine and lowland production areas of Austria were estimated before and after the implementation of basket fans, using life cycle assessment. Region-specific climate data were retrieved to determine the number of days with heat stress and to evaluate heat stress-induced productivity shortfalls in the baseline scenario (Sbasic). In the intervention scenario with increased ventilation (Svent), this decline was assumed to be eliminated due to the convective cooling effect of fans. For Sbasic, mean GWP, TAP and FEP impacts were estimated at 1.2 ± 0.09 kg CO2-, 21.1 ± 1.44 g SO2- and 0.1 ± 0.04 g P-equivalents per kg milk, respectively. Independent from the production system, in Svent, implementation of fans did not result in significant environmental impact changes, except for FEP of the alpine system (+5.9%). The latter reflects the comparatively high environmental costs of additional cooling regarding FEP (+2.3%) in contrast to GWP (+0.4%) and TAP (+0.1%). In conclusion, the estimated overall effects of mechanical ventilation on GWP, TAP and FEP of milk production were minor and the model calculations point to the potential of heat stress abatement to at least outweigh the environmental costs associated with fan production and operation. To confirm this trend, further assessments are needed, which should be based on primary data regarding the effectiveness of fan cooling to improve cow productivity, and on emission calculation schemes that are sensitive to environmental factors such as wind speed and temperature.

The value of manure - Manure as co-product in life cycle assessment.

Livestock production is important for food security, nutrition, and landscape maintenance, but it is associated with several environmental impacts. To assess the risk and benefits arising from livestock production, transparent and robust indicators are required, such as those offered by life cycle assessment. A central question in such approaches is how environmental burden is allocated to livestock products and to manure that is re-used for agricultural production. To incentivize sustainable use of manure, it should be considered as a co-product as long as it is not disposed of, or wasted, or applied in excess of crop nutrient needs, in which case it should be treated as a waste. This paper proposes a theoretical approach to define nutrient requirements based on nutrient response curves to economic and physical optima and a pragmatic approach based on crop nutrient yield adjusted for nutrient losses to atmosphere and water. Allocation of environmental burden to manure and other livestock products is then based on the nutrient value from manure for crop production using the price of fertilizer nutrients. We illustrate and discuss the proposed method with two case studies.

Impacts of global warming on confined livestock systems for growing-fattening pigs: simulation of heat stress for 1981 to 2017 in Central Europe.

In the mid-latitudes, pigs and poultry are kept predominantly in confined livestock buildings with a mechanical ventilation system. In the last decades, global warming has already been a challenge which causes hat stress for animals in such systems. Heat stress inside livestock buildings was assessed by a simulation model for the indoor climate, which is driven by meteorological parameters. Besides the meteorological conditions, the thermal environment inside the building depends on the sensible and latent energy release of the animals, the thermal properties of the building and the ventilation system and its control unit. For a site in Austria in the north of the Alpine Ridge, which is representative for confined livestock buildings for growing-fattening pigs in Central Europe, meteorological data between 1981 and 2017 were used for the model calculations of heat stress measures. This business-as-usual simulation over these 37 years resulted in an increase of the mean relative annual heat stress parameters in the range between 0.9 and 6.4% per year since 1981. In order to minimise the negative economic impact as the consequence of this positive trend of heat stress, adaptation measures are needed. The calculations for growing-fattening pigs show that such a simulation model for the indoor climate is an appropriate tool to determine the level of heat stress of livestock inside confined livestock buildings.

Reduction of greenhouse gas emissions from feed supply chains by utilizing regionally produced protein sources: the case of Austrian dairy production.

BACKGROUND: The aim of this study was to analyse the potential greenhouse gas emissions (GHGE) for regionally alternative produced protein-rich feedstuffs (APRFs) which are utilized for dairy cattle in Austria in comparison to solvent-extracted soybean meal (SBME). In addition to GHGE from agriculture and related upstream supply chains, the effects of land use change were calculated and were included in the results for GHGE. Furthermore, mixtures of APRFs were evaluated which provided energy and utilizable protein equivalent to SBME. RESULTS: Highest GHGE were estimated for SBME, mainly due to land use change-related emissions. Medium GHGE were found for distillers' dried grains with solubles, for seed cake and solvent-extracted meal from rapeseed and for lucerne cobs. Cake and solvent-extracted meal from sunflower seed as well as faba beans were loaded with lowest GHGE. Substituting SBME by nutritionally equivalent mixtures of APRFs, on average, resulted in a reduction of GHGE of 42% (22-62%). CONCLUSION: Utilization of locally produced APRFs shows clear advantages in terms of GHGE. Balanced mixtures of APRFs may offer specific benefits, as they allow for a combination of desirable nutritional value and reduced GHGE.