Measuring methane from ruminants is key for estimating breeding values for reduced emissions and for looking at responses to methane mitigation treatments. What is the best methods, equipment and brands for doing so.
https://doi.org/10.3390/methane1020008
https://www.mdpi.com/2076-2615/10/6/1004/pdf (https://doi.org/10.3390/ani10061004)
https://samples.ccafs.cgiar.org/measurement-methods/chapter-5-a-comparison-of-methodologies-for-measuring-methane-emissions-from-ruminants/
Increasing atmospheric concentrations of methane have led scientists to examine its sources of origin. Ruminant livestock can produce 250 to 500 L of methane per day. This level of production results in estimates of the contribution by cattle to global warming that may occur in the next 50 to 100 yr to be a little less than 2%. Many factors influence methane emissions from cattle and include the following: level of feed intake, type of carbohydrate in the diet, feed processing, addition of lipids or ionophores to the diet, and alterations in the ruminal micro-flora. Manipulation of these factors can reduce methane emissions from cattle. Many techniques exist to quantify methane emissions from individual or groups of animals. Enclosure techniques are precise but require trained animals and may limit animal movement. Isotopic and nonisotopic tracer techniques may also be used effectively. Prediction equations based on fermentation balance or feed characteristics have been used to estimate methane production. These equations are useful, but the assumptions and conditions that must be met for each equation limit their ability to accurately predict methane production. Methane production from groups of animals can be measured by mass balance, micro-meteorological, or tracer methods. These techniques can measure methane emissions from animals in either indoor or outdoor enclosures. Use of these techniques and knowledge of the factors that impact methane production can result in the development of mitigation strategies to reduce methane losses by cattle. Implementation of these strategies should result in enhanced animal productivity and decreased contributions by cattle to the atmospheric methane budget.
I fully Agree with Frank Veroustraete great explanation. Many years ago, with Jim Gibbs we used a wired probe to monitor ruminal methane concentrations. My take from that experiment was how little we knew about the rumen environment. in certain conditions the probe quickly saturated, whereas we found lower ruminal CH4 concentrations in conditions which were known to produce more methane emissions. This is odd because methane is highly insoluble, but it seemed that the changes in physicochemical properties of the rumen trapped more CH4. This means that variation of some tracer techniques might be due to the effect of ruminal gas holdup. I will not spend too much time on this effect, though, as Frank suggested, no matter which technique you use, knowing the problems and accounting for those errors will allow you to develop strategies to mitigate methane emissions. My focus will be no genetics, but the overall optimisation of the fermentative process in the rumen, as I believe, this is critically misunderstood.