Abstract: Greenhouse gas (GHG) mitigation is one of the main challenges facing agriculture, exacerbated by the increasing demand for food, in particular for livestock products. Production expansion needs to be accompanied by reductions in the GHG emission intensity of agricultural products, if significant increases in emissions are to be avoided. Suggested farm management changes often have systemic effects on farm, therefore their investigation requires a whole farm approach. At the same time, changes in GHG emissions arising offfarm in food supply chains (pre- or post-farm) can also occur as a consequence of these management changes. A modelling framework that quantifies the whole-farm, life-cycle effects of GHG mitigation measures on emissions and farm finances has been developed. It is demonstrated via a case study of sexed semen on Scottish dairy farms. The results show that using sexed semen on dairy farms might be a costeffective way to reduce emissions from cattle production by increasing the amount of lower emission intensity ‘dairy beef’ produced. It is concluded that a modelling framework combining a GHG life cycle analysis model and an economic model is a useful tool to help designing targeted agri-environmental policies at regional and national levels. It has the flexibility to model a wide variety of farm types, locations and management changes, and the LCA-approach adopted helps to ensure that GHG emission leakage does not occur in the supply chain.

Abstract: Greenhouse gas (GHG) mitigation is one of the main challenges faced by agriculture sector especially under an increasing demand for food. Production expansion needs to be accompanied by reductions in the GHG emission intensity of agricultural products. However, any uptakes of mitigation options by the farmers depend on the cost effectiveness of adopting such options as well as the farm characteristics. A highly effective mitigation option might not be practical for a farmer if the associated costs are high. A list of mitigation option implemented on different farm types with their cost effectiveness on farms would therefore be very useful for farmers as well as policy makers to make a decision. This paper aims to explore the use of three GHG mitigation options on different dairy farm groups in Scotland and determine the cost effectiveness of each of the options in those farm groups. The mitigation options considered for this paper are; i) use of sexed semen, ii) installing and using anaerobic digester and iii) increasing the share of concentrate diet. Farm level data from the Scottish Farm Accountancy dataset (FAS) was used and a cluster analysis was carried on to identify different dairy farm groups. The potential reduction of GHG emission per farm, including emissions arising from inputs used on the farm, under each of the option is then calculated using the GLEAM life cycle assessment model. An optimising farm level model, ScotFarm, was used on each of the farm groups to determine the optimum farm net margins under a baseline situation (with no options implemented) and three mitigation scenarios. The cost effectiveness of all three mitigation options are then determined based on reduction in GHG emission per farm and change in farm net margins under those options. Initial results for the sexed semen scenario suggest that this option can be cost effective for both efficient dairy farms (-£6.26/tCO2e) and medium-sized dairy farms (-£12.56/tCO2e). No Label