His research established a new paradigm in rumen metabolism research by publishing a series of papers that showed a reduction in methane production would result in a conservation of energy by capturing hydrogen which would normally be lost as methane; the ultimate effect was an increase in feed conversion efficiency and reduction in greenhouse gas emissions which was previously considered as biologically unachievable (see key references below). This work shows for the first time that it is possible to reprogram the rumen to improve digestive efficiency through deep understanding of the rumen microbiome. In addition to his current focus on gastrointestinal microbiology and metagenomics, Chris has started work on behavioural, digestive and metabolic factors that underpin feed conversion efficiency in ruminant livestock with an aim to identify phenotypic markers for the trait.