Abstract

The species composition of the rumen microbial community is shaped by the ruminant host and by characteristics of the ingested feed. The microbes present determine the ratios of volatile fatty acids, gases such as methane, and microbial protein formed from the feed. The rate of feed fermentation and the mix of products are important for animal production and for environmental impacts of ruminant farming. Differences in microbial community composition within a cohort of animals on a specific feed indicate differences in the rumen environment and presumably host animal genetics or early life history. Differences in the community when animals are on different feeds can be used to understand the impact of the feed on rumen function. Interpreting these community differences relies on understanding what might cause the selection of one community type over another. Recent research in New Zealand has developed a pipeline for studying rumen microbial community compositions. These tools have been used to help understand the basis of lower methane emissions from sheep fed forage brassica compared to ryegrass, and to understand what drives natural variations in methane emissions from sheep. This type of analysis is also starting to be used to investigate productivity differences within animal cohorts.

PH, Janssen, S Kittelmann, G Henderson, and H Seedorf

Proceedings of the New Zealand Society of Animal Production, Volume 74, Napier, 133-141, 2014