Accuracy of noninvasive breath methane measurements using Fourier transform infrared methods on individual cows

Abstract

Individual methane (CH(4)) production was recorded repeatedly on 93 dairy cows during milking in an automatic milking system (AMS), with the aim of estimating individual cow differences in CH(4) production. Methane and CO(2) were measured with a portable air sampler and analyzer unit based on Fourier transform infrared (FTIR) detection. The cows were 50 Holsteins and 43 Jerseys from mixed parities and at all stages of lactation (mean=156 d in milk). Breath was captured by the FTIR unit inlet nozzle, which was placed in front of the cow's head in each of the 2 AMS as an admixture to normal barn air. The FTIR unit was running continuously for 3 d in each of 2 AMS units, 1 with Holstein and another with Jersey cows. Air was analyzed every 20 s. From each visit of a cow to the AMS, CH(4) and CO(2) records were summarized into the mean, median, 75, and 90% quantiles. Furthermore, the ratio between CH(4) and CO(2) was used as a derived measure with the idea of using CO(2) in breath as a tracer gas to quantify the production of methane. Methane production records were analyzed with a mixed model, containing cow as random effect. Fixed effects of milk yield and daily intake of the total mixed ration and concentrates were also estimated. The repeatability of the CH(4)-to-CO(2) ratio was 0.39 for Holsteins and 0.34 for Jerseys. Both concentrate intake and total mixed ration intake were positively related to CH(4) production, whereas milk production level was not correlated with CH(4) production. In conclusion, the results from this study suggest that the CH(4)-to-CO(2) ratio measured using the noninvasive method is an asset of the individual cow and may be useful in both management and genetic evaluations.

Genetic and genomic relationship between methane production measured in breath and fatty acid content in milk samples from Danish Holsteins

“…The average CH 4 production was 395 g per day and the CH 4 production in grams per kilo ECM was 11.04. This is in agreement with other studies on large-scale CH 4 recordings in dairy cattle (Lassen et al 2012). Genetic and genomic heritabilities are shown in Table 2.…”

“…Several phenotypes were generated or extracted for the analysis (Table 1). Methane measuring equipment was installed in milking robots using a portable Fourier transformed infrared spectre measuring device making a registration of CH 4 and carbon dioxide every 5 s (Lassen et al 2012). This data was merged with traffic data from each milking robot so that each cow got a phenotype for each visit in the robot.…”

“…Several studies have worked on developing methods for large-scale phenotyping of individual CH 4 measurements (Garnsworthy et al 2012;Lassen et al 2012). These methods focus on CH 4 recordings while cows are being milked in automatic milking systems.…”

Applicability of short-term emission measurements for on-farm quantification of enteric methane

“…As with the GreenFeed unit, the animal's head position is considered (indirectly) in choosing whether to accept data; small emission peaks are discarded as they may have arisen when the head was away from the feed bin when the eructation occurred. The use of CO 2 concentration as an indicator of animal proximity could be advantageous if head position is found to affect measured concentration in the sample as claimed by Lassen et al (2012). These authors used this argument to support use of the CO 2 : CH 4 ratio as a proxy for DMP, with these authors claiming 'this ratio describes the methane production of each cow'.…”

“…As the majority of CO 2 production arises from mammalian oxidation of energy substrates, Lassen et al (2010) sought to allow for the effects of feed intake (roughage and concentrate intakes) as well as body weight on CO 2 : CH 4 ratio; they found this ratio to have a repeatability of 0.35 to 0.37 and proposed its use as a methane trait for genetic evaluation, without a requirement to scale up to DMP. Subsequently, Lassen et al (2012) made a 3-day study of the CO 2 :CH 4 ratio of 93 cows sampled during milking, finding a mean repeatability of the ratio from Holstein and Jersey cows of 0.37 and 0.33, respectively. Madsen et al (2010) used body weight and milk production as predictors of CO 2 production for housed cows and used the CO 2 : CH 4 ratio in exhaust gases from the barn to calculate a mean DMP.…”