P.PSH.1295 - Use of 3-NOP for methane mitigation by programming rumen microbiome in calves

Summary

The influence of dietary manipulation from birth on growth, methane production, and gastrointestinal microbial ecology in intensively raised dairy calves may be an effective strategy for dairy cow production but needs to be evaluated in extensive beef cattle systems. This proposal aims to demonstrate that 3-NOP, delivered to the calf from birth will influence the rumen microbiome development in a way that reduction in methane will persist for a long period of time after treatment has stopped. If effective, early life programming could present a viable, long-term method of methane reduction with lowered input costs over the lifetime of the animal.

Objectives

1. Determine whether early life exposure to livestock methane mitigant, 3-NOP conveys lasting methane reduction benefits, through rumen microbiome programming.
2. Compare conventional vs 3-NOP treated calves to show no adverse effect on later animal performance/animal health and animal welfare parameters.
3. Create knowledge of the underlying rumen microbial structure, function and biological driving forces that characterise the phenotype development of a low methane emitting animal as a consequence of an early-life application of 3-NOP.
4. Development of a practical application/delivery system for 3-NOP in grazing ruminants in the tropics that specifically targets Early Life microbiome programming and reduces lifetime methane emissions.

Key findings

Rumen fermentation profile of calves treated with 3-NOP showed a shift in fermentation from acetate to fatty acids, such as propionate and butyrate, and an increase in formic acid, which is a response to methane inhibition in ruminants. However, no significant differences were detected on methane production, rumen fermentation or body weight at four and eight months after the treatment withdrawal, between the control group and animals that received treatment early in life.

A sustained change to the bacterial groups in the rumen microbiome for treated calves was still seen at four months post-treatment for the previously treated calves. However, this did not relate to changes in rumen fermentation patterns, or methane production, after the treatment withdrawal, likely suggesting that either these alterations are quantitatively small or there has been an alteration in their fermentative function due to changes in the rumen.

The findings suggest that a greater dose and/or earlier intervention (eg. direct dosing) might be required to have a significant lasting effect on methane production later in life.

Benefits to industry

The objective of the project was to investigate the potential of short term exposure to methane mitigant, 3-NOP, in early life of calves could deliver lasting mitigation through rumen microbiome modification. Unfortunately, this objective was not achieved, and a lower methane emission profile was not retained at measurement points four and eight months after treatment was withdrawn.

MLA action

Results have been socialised with local and global research partners to better inform research on early-life programming for methane mitigation.

Future research

Future research might benefit from exploring the impact of directly dosing animals from birth. Despite the lack of success in this project, early life programming should be further studied and considered as a strategy for more controlled farming systems, not only as methane abatement strategy but also targeting other desirable phenotypes, such as feed efficiency, health parameters or diet transitioning. We do not rule out the use of this strategy in grazing systems in the future, but a better understanding of the mode of action, window of intervention, dose and new delivery methods should be studied and developed under more controlled conditions before attempting to deploy it in a grazing system.