Investigating approaches in dairy farming towards mitigation of Greenhouse Gas (GHG) emissions: Atmospheric concentrations, nutrient utilisation and

Title: Investigating approaches in dairy farming towards mitigation of Greenhouse Gas (GHG) emissions: Atmospheric concentrations, nutrient utilisation and indices of milk production as factors of prediction

GHG gas emissions, particularly methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) from ruminant livestock, contribute significantly to global warming. In the UK, the agrifood system produces approximately 23% of emissions. Dairy cattle, have a great environmental impact as methane is released directly from digestive feed, and additionally decomposing manure creates CH4, NO2 and ammonia.

Approaches to mitigating the production of GHGs by agricultural animals are recognised as multifactorial (e.g. Cool Farm Tool), but information on the success of current practices in contemporary livestock production is limited. Such strategies include: selected cattle genetics; feed additives (eg Rumitech, Maxammon, Monensin); altering dietary forage to concentrate ratios (starch-based; cellulosic/non-starch polysaccharide); low or high input systems; and the extent to which nitrogen-containing excreta is captured as fertiliser in crops for animal feeds in a "circular" system.

To address this critical environmental issue, we will investigate nutritional practices to mitigate enteric and excreted GHG emissions from cattle in different farming systems. The student will investigate such practices across dairy farms and determine the extent to which outcomes (cow health; digestive efficiency; indices for milk) associate with GHG emissions by both individual animals and collectively in the farm atmosphere.