Search

This study proposed a method for measuring the methane (CH 4 )/carbon dioxide (CO 2 ) ratio from individual beef cattle under on-farm conditions and estimated the variance components of the CH 4 /CO 2 ratio. Gas measurements were conducted using 166 Japanese Black cattle group-housed in pens equipped with individual feed bins. The gas containing the animal's breath was measured individually after concentrate feeding by covering the feed bin with a sheet with sampling inlets. Measurements were performed six times (three consecutive days, twice daily) per individual. Most of the sampled gas contained more than 1000 ppm of the mean background-corrected CO 2 , suggesting that the method proposed in this study successfully collected sufficient breath concentration to accurately measure the CH 4 /CO 2 ratio. The between-animal variance accounted for 31.7% of the total variance in the CH 4 /CO 2 ratio. The results showed that the gas collection method proposed in this study could be a useful tool for measuring the CH 4 /CO 2 ratio under on-farm conditions. The variance component obtained from this study will help to establish protocols for generating data for genetic evaluation and performing dietary experiments with sufficient statistical power., (© 2024 Japanese Society of Animal Science.)

This study investigated the physiological characteristics and carcass performance associated with residual methane emissions (RME), and the effects of bull differences on CH 4 -related traits in Japanese Black cattle. Enteric methane (CH 4 ) emissions from 156 Japanese Black cattle (111 heifers and 45 steers) were measured during early fattening using the sniffer method. Various physiological parameters were investigated to clarify the physiological traits between the high, middle, and low RME groups. CH 4 -related traits were examined to determine whether bull differences affected progeny CH 4 emissions. Ruminal butyrate and NH 3 concentrations were significantly higher in the high-RME group than in the low-RME group, whereas the propionate content was significantly higher in the low-RME group. Blood urea nitrogen, β-hydroxybutyric acid, and insulin concentrations were significantly higher, and blood amino acids were lower in the high-RME group than in the other groups. No significant differences were observed in the carcass traits and beef fat composition between RME groups. CH 4 -related traits were significantly different among bull herds. Our results show that CH 4 -related traits are heritable, wherein bull differences affect progeny CH 4 production capability, and that the above-mentioned rumen fermentations and blood metabolites could be used to evaluate enteric methanogenesis in Japanese Black cattle., (© 2024 Japanese Society of Animal Science.)

In this study, using enteric methane emissions, we investigated the metabolic characteristics of Japanese Black cattle. Their methane emissions were measured at early (age 13 months), middle (20 months), and late fattening phases (28 months). Cattle with the highest and lowest methane emissions were selected based on the residual methane emission values, and their liver transcriptome, blood metabolites, hormones, and rumen fermentation characteristics were analyzed. Blood β-hydroxybutyric acid and insulin levels were high, whereas blood amino acid levels were low in cattle with high methane emissions. Further, propionate and butyrate levels differed depending on the enteric methane emissions. Hepatic genes, such as SERPINI2, SLC7A5, ATP6, and RRAD, which were related to amino acid transport and glucose metabolism, were upregulated or downregulated during the late fattening phase. The above mentioned metabolites and liver transcriptomes could be used to evaluate enteric methanogenesis in Japanese Black cattle., (© 2022. The Author(s).)

The purpose of this study was to investigate the carbon dioxide (CO 2 ) concentration in the sampled gas to avoid low concentration of breath while measuring the methane (CH 4 )/CO 2 ratio using the sniffer method. This study also assessed the effect of selective elimination by applying the threshold of CO 2 concentration to the CH 4 /CO 2 ratio. The gas measurement in the automatic milking system was conducted with 26 multiparous Holstein cows using an electric fan to manipulate the CO 2 concentration in the sampled gas. Four different thresholds of the background-corrected CO 2 concentrations (0, 0.025, 0.05, and 0.1%) were applied to every 1-s value of the individual gas measurement. Subsequently, three different upper limits of the proportion of eliminated values (none, 0.5, and 0.33) were applied to the individual records per milking. The results showed that the sampled gas must contain more than 0.1% of the corrected CO 2 concentration to enable accurate calculation of the CH 4 /CO 2 ratio. It is recommended that at least half of the values in the data be larger than the threshold of the corrected CO 2 concentration for unbiased measurement of the CH 4 /CO 2 ratio., (© 2022 Japanese Society of Animal Science.)

The aim of this study was to develop prediction equations for methane (CH 4 ) emissions from lactating cows using the CH 4 /carbon dioxide (CO 2 ) ratio in the breath measured in the automatic milking system (AMS) and to evaluate the predicted values and factors affecting the CH 4 /CO 2 ratio. The model development was conducted using a dataset determined in respiration chambers or head boxes (n = 121). Then, gas measurements in the AMS as well as in the head box were carried out with six lactating cows fed one of three different levels of neutral detergent fiber (NDF) content, following a 3 × 3 Latin square experimental design. The obtained equation that is suitable for practical use on farms to predict CH 4 was CH 4 (L/day) = -507 + 0.536 live weight (kg) + 8.76 energy-corrected milk (kg/day) + 5,029 CH 4 /CO 2 (adjusted R 2  = 0.83; root mean square error = 40.8 L/day). Results showed that the predicted values correlated positively with the observed values, the determined CH 4 /CO 2 ratio increased with increasing dietary NDF content, and the detected eructation rate was in the normal range. On the other hand, the CH 4 /CO 2 ratio was affected by the time interval between measurement and last eating before the measurement., (© 2021 The Authors. Animal Science Journal published by John Wiley & Sons Australia, Ltd on behalf of Japanese Society of Animal Science.)

The objectives of this study were to estimate genetic parameters and to perform a genome-wide association study (GWAS) for predicted methane-related traits in Japanese Black steers. The methane production and yield traits were predicted using on-farm measurable traits, such as dry matter intake and average daily gain. A total of 4,578 Japanese Black steers, which were progenies of 362 sires genotyped with imputed 551,995 single nucleotide polymorphisms (SNPs), had phenotypes of predicted methane-related traits during the total fattening period (52 weeks). For the estimation of genetic parameters, the estimated heritabilities were moderate (ranged from 0.57 to 0.60). In addition, the estimated genetic correlations of methane production traits with most of carcass traits and feed-efficiency traits were unfavorable, but those of methane yield traits were favorable or low. For the GWAS, no genome-wide significant SNP was detected, but a total of four quantitative trait locus (QTL) regions that explained more than 5.0% of genetic variance were localized on the genome, and some candidate genes associated with growth and feed-efficiency traits were located on the regions. Our results suggest that the predicted methane-related traits are heritable and some QTL regions for the traits are localized on the genome in Japanese Black steers., (© 2020 Japanese Society of Animal Science.)

The objective of this study was to develop a prediction equation for methane-related traits in beef cattle and evaluate this equation using datasets with different cattle breeds and roughage rates. Enteric methane emission (CH 4 , l/day) was measured using open-circuit respiration chambers. Dry matter intake (DMI, kg/day), body weight (BW, kg), daily gain (DG, kg), total digestible nutrients (TDN, %DMI), and roughage rate (Rrate, %) were used as independent variables, and methane-related traits-CH 4 , CH 4 per DMI (CH 4 /DMI, l/kg), and methane conversion factor (MCF, %)-were used as dependent variables. The best-fit equations to predict methane-related traits using a total of 76 records were CH 4  = -676.7 + 0.04194 × BW + 29.88 × DMI + 7.883 × TDN + 4.367 × Rrate, CH 4 /DMI = -52.24 - 1.193 × 10 -3  × BW - 5.905 × DG + 1.077 × TDN + 0.5008 × Rrate, and MCF = -11.43 - 5.308 × 10 -4  × BW - 1.223 × DG + 0.2336 × TDN + 0.1157 × Rrate. The predictive ability of the developed equations differed between roughage rates but not between breeds. For CH 4 , the predictive ability of the developed equations was better compared with previously reported equations in the low roughage rate dataset, but not in the high roughage rate dataset. Our results suggest that the developed equations of methane-related traits can be applied in beef cattle fed with low roughage diets., (© 2020 Japanese Society of Animal Science.)

We conducted a meta-data analysis to develop prediction equations to estimate enteric methane (CH 4 ) emission from beef cattle in Southeast Asia. The dataset was obtained from 25 studies, which included 332 individual observations on nutrient intakes, digestibilities, and CH 4 emissions. Cattle were provided tropical forage or rice straw, with or without concentrates in individual pens equipped with indirect open-circuit head hood apparatus. The simplest and best equation to predict daily CH 4 emission was CH 4 (g/day) = 22.71 (±1.008) × dry matter intake (DMI, kg/day) + 8.91 (±10.896) [R 2  = 0.77; root mean square error (RMSE) = 19.363 g/day]. The best equation to predict CH 4 energy as a proportion of gross energy intake (CH 4 -E/GEI, J/100 J) was obtained using DMI per body weight (DMIBW, kg/100 kg), content (g/100 g DM) of ether extract (EE) and crude protein (CP), and DM digestibility (DMD, g/100 g); CH 4 -E/GEI = -0.782 (±0.2526) DMIBW - 0.436 (±0.0548) EE - 0.073 (±0.0218) CP + 0.049 (±0.0097) DMD + 8.654 (±0.6517) (R 2  = 0.39; RMSE = 1.3479 J/100 J GEI). It was indicated that CH 4 emissions from beef cattle in Southeast Asia are predictable using present developed models including simple indices., (© 2018 Japanese Society of Animal Science.)

Methane (CH(4)) is the second most important greenhouse gas (GHG) and that emitted from enteric fermentation in livestock is the single largest source of emissions in Japan. Many factors influence ruminant CH(4) production, including level of intake, type and quality of feeds and environmental temperature. The objectives of this review are to identify the factors affecting CH(4) production in ruminants, to examine technologies for the mitigation of CH(4) emissions from ruminants, and to identify areas requiring further research. The following equation for CH(4) prediction was formulated using only dry matter intake (DMI) and has been adopted in Japan to estimate emissions from ruminant livestock for the National GHG Inventory Report: Y = -17.766 + 42.793X - 0.849X(2), where Y is CH(4) production (L/day) and X is DMI (kg/day). Technologies for the mitigation of CH(4) emissions from ruminants include increasing productivity by improving nutritional management, the manipulation of ruminal fermentation by changing feed composition, the addition of CH(4) inhibitors, and defaunation. Considering the importance of ruminant livestock, it is essential to establish economically feasible ways of reducing ruminant CH(4) production while improving productivity; it is therefore critical to conduct a full system analysis to select the best combination of approaches or new technologies to be applied under long-term field conditions.