The NZAGRC is committed to providing information regarding agricultural greenhouse gases research and overview information.

Below are a list of publications and reports from a variety of sources that may be useful if you're interested in agricultural greenhouse gases. They range from information for those who have a general interest in greenhouse gas mitigation options and technologies through to very specific science papers on the various gases, technologies and mitigation solutions.

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Development of an improved representation of rumen digesta outflow in a mechanistic and dynamic model of a dairy cow, Molly

Pablo Gregorini, Pierre Beukes, Garry Waghorn, David Pacheco, Mark Hanigan, Development of an improved representation of rumen digesta outflow in a mechanistic and dynamic model of a dairy cow, Molly, Ecological Modelling, Volume 313, 2015, Pages 293-306, ISSN 0304-3800,


Accurate predictions of outflow of digesta from the rumen are critical for improving modeling of feed intake, rumen function and fermentation patterns of ruminants. The main objective of this work was to develop an improved representation of rumen digesta outflow in the Molly model. The work is primarily an integration of existing knowledge of rumen digestion responsible for variations in digesta outflows in ruminants, and describes the structure and function of the new development, assessing the new model in terms of ruminal outflow and fermentation in response to different feeding scenarios. The present development includes three changes to the model: (1) a medium-size particle pool was added to the rumen which was assumed to ferment and pass from the rumen; (2) particulate passage was made a function of particle size, particle concentrations in the rumen, and liquid passage rate; and (3) fermentation rate was made a function of particle surface area in the medium and small particle pools. Although prediction accuracy of digestive functions was not substantially improved by the change in model structure, the model now reproduces observed patterns of variation in rumen function as affected by the food intake and dietary particle size compared with those reported in the literature, which was not previously the case. It also reproduces more realistic trends in rumen fermentation patterns, digestion and methane yields. The concepts embedded in the new development capture underlying biological mechanisms driving the variation in digesta outflows from the rumen that were not captured before.

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