There’s an innovative new way to potentially monitor the digestive activity, environmental impact, and health of dairy cows – and it’s as simple as breathing.
Dairy nutrition researcher Dr. Mutian Niu, Assistant Professor of Animal Nutrition at ETH Zurich, Switzerland, explained the science of “exhalomics” on a recent edition of the Dairy Nutrition Blackbelt podcast. Niu said exhalomics is the study of metabolites and compounds found in exhaled breath.
Exhalomics have already been studied in humans and mice. One example of an application is the early detection of lung cancer in humans. In ruminant species, Niu said the technology is especially exciting because the rumen releases gases that are exhaled in the breath, providing a proxy for rumen fermentation activity by measuring rumen volatile fatty acids.
That opens up a world of investigative possibilities for ruminant nutrition research and solves a critical challenge for Niu and his colleagues. When he studied in the U.S. at Penn State University and the University of California-Davis, he had ready access to rumen-cannulated cows from which rumen fluid samples could be collected. In all of Switzerland, there are only 6, and 4 of them are in his research facility at Zurich.
Studying exhaled breath provides a non-invasive alternative to access a window into rumen fermentation activity. So far, Niu’s team has been using exhalomics to measure methane emissions based on different diets. They use a GreenFeed sampling device to collect the exhalation samples, and have concurrently evaluated other compounds in those samples.
They initially assessed whether exhalomics could accurately measure volatile fatty acids (VFA) when compared to more traditional rumen sampling methods. They found a reasonable correlation between the two when assessing fluctuating acetate, propionate, and butyrate levels relative to feed intake. The correlation between results also was strong when they measured the VFAs in a 16% dry-matter starch ration versus a 6% starch ration.
Monitoring changes in rumen dynamics can be predictive of digestive efficiency and balance. For example, Niu said it can predict changes in rumen pH and provide an early warning for the development of subacute ruminal acidosis (SARA).
“By directly looking at the metabolic profile via exhalomics, eventually I hope we can get a real-time, more frequent and non-invasive aspect to reflect rumen fermentation,” Niu stated.
And the potential for exhalomics in dairy cattle spans beyond the rumen. Researchers also are working to pinpoint biomarkers in exhaled breath to promote early detection of respiratory disease, ketosis, mastitis, metritis, and displaced abomasum in real time.
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