A method of determining the feed efficiency and methane production of a ruminating animal comprising analyzing the number and/or diversity of a bacterial taxon of a microbiome of the animal or of a gene content of said microbiome, wherein a number and/or diversity of said taxon below a predetermined level is indicative of an animal having a high feed efficiency and low methane production, or a number of genes below a predetermined level is indicative of an animal having a high feed efficiency and low methane production.

The present disclosure provides consumable compositions comprising a haloalkane and a medium chain triglyceride, methods of preparing the consumable composition, and methods of administering the consumable compositions.