A Review of Enteric Methane Emission Measurement Techniques in Ruminants

Abstract

To identify relationships between animal, dietary and management factors and the resulting methane (CH4) emissions, and to identify potential mitigation strategies for CH4 production, it is vital to develop reliable and accurate CH4 measurement techniques. This review outlines various methods for measuring enteric CH4 emissions from ruminants such as respiration chambers (RC), sulphur hexafluoride (SF6) tracer, GreenFeed, sniffer method, ventilated hood, facemask, laser CH4 detector and portable accumulation chamber. The advantages and disadvantages of these techniques are discussed. In general, RC, SF6 and ventilated hood are capable of 24 h continuous measurements for each individual animal, providing accurate reference methods used for research and inventory purposes. However, they require high labor input, animal training and are time consuming. In contrast, short-term measurement techniques (i.e., GreenFeed, sniffer method, facemask, laser CH4 detector and portable accumulation chamber) contain additional variations in timing and frequency of measurements obtained relative to the 24 h feeding cycle. However, they are suitable for large-scale measurements under commercial conditions due to their simplicity and high throughput. Successful use of these techniques relies on optimal matching between the objectives of the studies and the mechanism of each method with consideration of animal behavior and welfare. This review can provide useful information in selecting suitable techniques for CH4 emission measurement in ruminants.

Measurement of Enteric Methane Emissions by the SF6 Technique Is Not Affected by Ambient Weather Conditions

“…Wind direction has been suggested as one of the major factors potentially affecting methane measurements in grazing studies [ 4 , 32 ]. However, as we have found that wind speed during our measurements did not influence the modified SF 6 technique, and as cows orient themselves in many directions at different times during the day, we also surmise that wind direction does not influence the technique.…”

“…The respiration chamber method is considered the “gold standard” [ 1 ] and has been used by many researchers over the past 5 decades. Two recently developed methods include the sniffer method [ 2 ] and the Greenfeed or C-lock method [ 3 ] which have been increasingly used in recent research [ 4 ]. However, due to the limited sampling times used in these latter methods [ 5 ], and the marked diurnal patterns in the magnitude of MeP from dairy cows [ 6 ], some researchers have questioned the suitability of these recent methods for quantifying daily MeP of individual cows [ 7 , 8 ].…”

Challenges and opportunities for quantifying greenhouse gas emissions through dairy cattle research in developing countries

“…There are a number of methods developed for quantifying GHG emissions from dairy cattle under research conditions. For example, enteric CH 4 emissions from dairy cattle can be measured by respiration chamber, sulphur hexafluoride tracer technique, ventilated hood /face mask and using the Greenfeed system (Hammond et al ., 2016; Zhao et al ., 2020). However, all these methods require substantial facilities and expertise to accurately quantify CH 4 emissions.…”

“…In many cases, milk in developing countries comes from these smallholder systems. For instance, 85% of total Kenya milk production comes from smallholders (Gerosa and Skoet, 2013) and in Pakistan 95% of milk consumed is from local and unpackaged milk sources produced by smallholder farmers (Zia et al, 2011). Intensification of the dairy system is common in developing countries as a response to increased demand for milk.…”

The Biopolitics of Cattle Methane Emissions Reduction: Governing Life in a Time of Climate Change

“…So too is the use of "sexed semen" during artificial insemination to lessen the likelihood of unwanted male calves from dairy cows, reducing the "waste" and overall emissions intensities of the products produced by the herd (Gerber et al 2013). Low methane herd management also works by manipulating the spaces in which cattle live: planting grasses that are easily digestible and shifting from unrestricted grazing systems to rotating systems means pastures recover quicker, suppressing the growth of less digestible weeds that slow growth and increase overall emissions (Zhao et al 2020).…”