A universal equation to predict methane production of forage-fed cattle in Australia

The methods for estimating methane emissions from cattle as used in the Australian national inventory are based on older data that have now been superseded by a large amount of more recent data. Recent data suggested that the current inventory emissions estimates can be improved. To address this issue, a total of 1034 individual animal records of daily methane production (MP) was used to reassess the relationship between MP and each of dry matter intake (DMI) and gross energy intake (GEI). Data were restricted to trials conducted in the past 10 years using open-circuit respiration chambers, with cattle fed forage-based diets (forage >70%). Results from diets considered to inhibit methanogenesis were omitted from the dataset. Records were obtained from dairy cattle fed temperate forages (220 records), beef cattle fed temperate forages (680 records) and beef cattle fed tropical forages (133 records). Relationships were very similar for all three production categories and single relationships for MP on a DMI or GEI basis were proposed for national inventory purposes. These relationships were MP (g/day) = 20.7 (±0.28) × DMI (kg/day) (R2 = 0.92, P < 0.001) and MP (MJ/day) = 0.063 (±0.008) × GEI (MJ/day) (R2 = 0.93, P < 0.001). If the revised MP (g/day) approach is used to calculate Australia’s national inventory, it will reduce estimates of emissions of forage-fed cattle by 24%. Assuming a global warming potential of 25 for methane, this represents a 12.6 Mt CO2-e reduction in calculated annual emissions from Australian cattle

Towards sustainable sources of omega-3 long-chain polyunsaturated fatty acids in Northern Australian tropical crossbred beef steers through single nucleotide polymorphisms in lipogenic genes for meat eating quality

This study aimed to identify single nucleotide polymorphisms (SNP) in lipogenic genes of northern Australian tropically adapted crossbred beef cattle and to evaluate associations with healthy lipid traits of the Longissimus dorsi (loin eye) muscle. The hypothesis tested was that there are significant associations between SNP loci encoding for the fatty acid binding protein 4 (FABP4), stearoyl-CoA desaturase (SCD) and fatty acid synthase (FASN) genes and human health beneficial omega-3 long-chain polyunsaturated fatty acids (ω3 LC-PUFA) within the loin eye muscle of northern Australian crossbred beef cattle. Brahman, Charbray, and Droughtmaster crossbred steers were fed on Rhodes grass hay augmented with desmanthus, lucerne, or both, for 140 days and the loin eye muscle sampled for intramuscular fat (IMF), fat melting point (FMP), and fatty acid composition. Polymorphisms in FABP4, SCD, and FASN genes with significant effects on lipid traits were identified with next-generation sequencing. The GG genotype at the FABP4 g.44677239C>G locus was associated with higher proportion of linoleic acid than the CC and CG genotypes (p T locus indicated that the TT genotype had significantly higher eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids than GG genotype (p < 0.05). Significant correlations (p < 0.05) between FASN SNP and IMF, saturated and monounsaturated fatty acids were observed. These results provide insights into the contribution of lipogenic genes to intramuscular fat deposition and SNP marker-assisted selection for improvement of meat-eating quality, with emphasis on alternate and sustainable sources of ω3 LC-PUFA, in northern Australian tropical crossbred beef cattle, hence an acceptance of the tested hypothesis

Single nucleotide polymorphisms in the fatty acid binding protein 4, fatty acid synthase and stearoyl-CoA desaturase genes influence carcass characteristics of tropical crossbred beef steers

This study explored the identification of single nucleotide polymorphisms (SNP) in fatty acid binding protein 4 (FABP4), stearoyl-CoA desaturase (SCD), and fatty acid synthase (FASN) genes that may influence the carcass traits of tropical crossbred beef cattle. The hypothesis tested was that SNP in the FABP4, SCD, and FASN genes are associated with chiller-assessed carcass traits of tropically adapted northern Australian crossbred beef cattle. Fifty Bos indicus and Bos taurus crossbred steers were backgrounded on either buffel grass only, or buffel grass and desmanthus mixed pastures for 147 days and finished in a commercial feedlot for 110 days. Steers were slaughtered within 48 h of leaving the feedlot within a lairage period not exceeding 12 h and carcasses graded 12 h after slaughter. Next-generation sequencing of the FASN, FABP4, and SCD genes identified multiple SNP loci that were correlated and significantly associated with carcass traits. The FABP4 g.44677205A>G locus was significantly associated with hump height and correlated with loin eye muscle area (EMA; p A locus was associated with subcutaneous fat depth and marbling score (p < 0.05). The CC genotype had a higher subcutaneous fat depth and marbling score (p < 0.05) than the AA genotype. Significant correlations were observed between carcass marbling score and subcutaneous fat depth within the FASN SNP locus (p < 0.05). Therefore, the hypothesis that SNP in the FABP4, SCD, and FASN genes are associated with chiller-assessed carcass traits of tropically adapted northern Australian crossbred beef cattle was accepted. These findings suggest that SNP in the FABP4, SCD, and FASN genes may be used in carcass grading and meat quality improvement through marker-assisted selection of northern Australian crossbred beef cattle

Using plant wax markers to estimate the diet composition of grazing Holstein dairy cows

The objective of this study was to test whether diet selection of dairy cows under grazing conditions could be estimated using plant wax markers. Furthermore, differences between 2 cow strains and the effect of concentrate supplementation on plant species selection were investigated. The experiment was a study with a crossover design performed on an organic farm with 12 Swiss Holstein cows and 12 New Zealand Holstein cows. Both experimental periods consisted of a 21-d adaptation and a 7-d measurement period. All cows grazed full time in a rotational stocking system and received either no concentrate or 6 kg/d of a commercial cereal-grain mix. Representative herbage samples of each grazed paddock were taken and botanical composition of subsamples was manually determined. The average proportions of the plant species were 27.8% Lolium perenne, 6.1% Dactylis glomerata, 10.4% Trifolium repens, and 9.0% Taraxacum officinale. Other grass species were merged as "other grass" (38.2%) and other forb species as "other forbs" (8.5%). n-Alkanes, long-chain fatty acids, and long-chain alcohols (LCOH) were analyzed in the samples of plant species, concentrate, and feces from each cow. A linear discriminant analysis indicated that diet components were differentiated best with LCOH (96%) and worst with the combination of all marker groups together (12%). For each marker, the fecal marker recovery (FR) relative to dosed ytterbium was determined in 2 ways. Estimation of diet composition was performed with the software "EatWhat," and results were compared with botanical composition with the Aitchison distance. The results indicate that the diet composition of grazing dairy cows can be estimated using plant wax markers. Additionally, the calculation of FR led to mostly reliable results, yet this approach needs further validation. The most accurate estimation was achieved with the marker combination of n-alkanes and LCOH with a correction for FR. Less accurate estimations were achieved with long-chain fatty acids alone or in combination with n-alkanes. No difference relating to diet selection between the 2 cow strains was recorded, but supplemented cows apparently ingested higher proportions of T. repens than nonsupplemented cows. Awareness that supplementation influences selection behavior of grazing dairy cows may lead to adaptations in botanical composition of the pasture according to the demand of the animals

Prediction of enteric methane production, yield and intensity of beef cattle using an intercontinental database

Enteric methane (CH4) production attributable to beef cattle contributes to global greenhouse gas emissions. Reliably estimating this contribution requires extensive CH4 emission data from beef cattle under different management conditions worldwide. The objectives were to: 1) predict CH4 production (g d¬-1 animal-1), yield [g (kg dry matter intake; DMI)-1] and intensity [g (kg average daily gain)-1] using an intercontinental database (data from Europe, North America, Brazil, Australia and South Korea); 2) assess the impact of geographic region, and of higher- and lower-forage diets. Linear models were developed by incrementally adding covariates. A K-fold cross-validation indicated that a CH4 production equation using only DMI that was fitted to all available data had a root mean square prediction error (RMSPE; % of observed mean) of 31.2%. Subsets containing data with ≥ 25% and ≤ 18% dietary forage contents had an RMSPE of 30.8 and 34.2%, with the all-data CH4 production equation, whereas these errors decreased to 29.3 and 28.4%, respectively, when using CH4 prediction equations fitted to these subsets. The RMSPE of the ≥ 25% forage subset further decreased to 24.7% when using multiple regression. Europe- and North America-specific subsets predicted by the best performing ≥ 25% forage multiple regression equation had RMSPE of 24.5 and 20.4%, whereas these errors were 24.5 and 20.0% with region-specific equations, respectively. The developed equations had less RMSPE than extant equations evaluated for all data (22.5 vs. 23.2%), for higher-forage (21.2 vs. 23.1%), but not for the lower-forage subsets (28.4 vs. 27.9%). Splitting the dataset by forage content did not improve CH4 yield or intensity predictions. Predicting beef cattle CH4 production using energy conversion factors, as applied by the Intergovernmental Panel on Climate Change, indicated that adequate forage content-based and region-specific energy conversion factors improve prediction accuracy and are preferred in national or global inventories

Methane production in ruminant animals

Agriculture is a significant source of GHGs globally and ruminant livestock animals are one of the largest contributors to these emissions, responsible for an estimated 14% of GHGs (CH4 and N2O combined) worldwide. A large portion of GHG fluxes from agricultural activities is related to CH4 emissions from ruminants. Both direct and indirect methods are available. Direct methods include enclosure techniques, artificial (e.g. SF6) or natural (e.g. CO2) tracer techniques, and micrometeorological methods using open-path lasers. Under the indirect methods, emission mechanisms are understood, where the CH4 emission potential is estimated based on the substrate characteristics and the digestibility (i.e. from volatile fatty acids). These approximate methods are useful if no direct measurement is possible. The different systems used to quantify these emission potentials are presented in this chapter. Also, CH4 from animal waste (slurry, urine, dung) is an important source: methods pertaining to measuring GHG potential from these sources are included

Polymorphism in a T-cell receptor variable gene is associated with susceptibility to a juvenile rheumatoid arthritis subset

This report demonstrates a T-cell receptor (Tcr) restriction fragment length polymorphism, defined by a Tcrb-V6.1 gene probe and Bgl II restriction enzyme, to be absolutely correlated with allelic variation in the coding sequence of a Tcrb-V6.1 gene. A pair of non-conservative amino acid substitutions distinguish the Tcrb-V6.1 allelic variants. An association of this Tcrb-V6.1 gene allelic variant with one form of juvenile rheumatoid arthritis (JRA) was established in a cohort of 126 patients. The association was observed in patients possessing the HLA-DQA1*0101 gene. Among HLA-DQA*0101 individuals, 19 of 26 patients (73.1%) carried one particular Tcrb-V6.1 gene allele as opposed to 11 of 33 controls (33%; p<0.005). Haplotypes carrying this HLA gene have previously been shown to confer increased risk for progression of arthritis in JRA. This demonstration of a disease-associated Tcrb-V gene allelic variant has not, to our knowledge, been previously reported and supports the contribution of polymorphism in the Tcr variable region genomic repertoire to human autoimmune disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46750/1/251_2004_Article_BF00166831.pd