Can concentrations of trans octadecenoic acids in milk fat be used to predict methane yields of dairy cows

There is a need to develop simple, accurate methods for predicting methane emissions, yields and intensities of dairy cows. Several studies have focussed on the relationship between the concentrations of trans-10 plus trans-11 C18:1 fatty acids in milk fat and methane yield. The aim of the present study was to perform a meta-analysis to quantify relationships between the concentrations of various trans isomers of C18:1 in milk fat and methane emissions (g/day), methane yield (g/kg dry-matter intake) and methane intensity (g/kg energy-corrected milk yield). Data were from seven experiments encompassing 23 different diets and 220 observations of milk fatty acid concentrations and methane emissions. Univariate linear mixed-effects regression models were fitted to the data with the linear term as a fixed effect and with experiment and observation within experiment as random effects. Concentrations of trans-9, trans-10, trans-11 and trans-10 plus trans-11 isomers of C18:1 were poorly related to methane emissions, yields and intensities, with the best relationships being between trans-10 C18:1 and methane emissions (R2 = 0.356), trans-10 C18:1 and methane yield (R2 = 0.265) and trans-10 plus trans-11 C18:1 and methane intensity (R2 = 0.124). The data indicated that the relationships between trans-10 C18:1 and methane metrics were not linear, but were biphasic and better described by an exponential model. However, even exponential models poorly fitted the data. It is concluded that the concentrations of trans isomers of C18:1 have limited potential to accurately predict methane emissions, yields or intensities of dairy cows.

[1]  B. Hayes,et al.  Reducing the carbon footprint of Australian milk production by mitigation of enteric methane emissions , 2016 .

[2]  P. Moate,et al.  Milk production and composition, and methane emissions from dairy cows fed lucerne hay with forage brassica or chicory , 2016 .

[3]  N. Poulsen,et al.  Genetic and genomic relationship between methane production measured in breath and fatty acid content in milk samples from Danish Holsteins , 2016 .

[4]  R. M. Herd,et al.  A universal equation to predict methane production of forage-fed cattle in Australia , 2016 .

[5]  J. Dijkstra,et al.  Meta-analysis of relationships between enteric methane yield and milk fatty acid profile in dairy cattle. , 2014, Journal of dairy science.

[6]  P. Moate,et al.  A modified sulphur hexafluoride tracer technique enables accurate determination of enteric methane emissions from ruminants , 2014 .

[7]  P. Moate,et al.  Methane emissions of dairy cows cannot be predicted by the concentrations of C8:0 and total C18 fatty acids in milk , 2014 .

[8]  Shinichi Nakagawa,et al.  A general and simple method for obtaining R2 from generalized linear mixed‐effects models , 2013 .

[9]  V. Fievez,et al.  Milk odd- and branched-chain fatty acids as biomarkers of rumen function—An update , 2012 .

[10]  P. Moate,et al.  Background matters with the SF6 tracer method for estimating enteric methane emissions from dairy cows: A critical evaluation of the SF6 procedure , 2011 .

[11]  D. Sauvant,et al.  Influences des régimes et de leur fermentation dans le rumen sur la production de méthane par les ruminants , 2011 .

[12]  K. Beauchemin,et al.  Prediction of enteric methane output from milk fatty acid concentrations and rumen fermentation parameters in dairy cows fed sunflower, flax, or canola seeds. , 2011, Journal of dairy science.

[13]  J. Dijkstra,et al.  Relationships between methane production and milk fatty acid profiles in dairy cattle , 2011 .

[14]  J. Peyraud,et al.  The effects of starch and rapidly degradable dry matter from concentrate on ruminal digestion in dairy cows fed corn silage-based diets with fixed forage proportion. , 2011, Journal of dairy science.

[15]  D. Morgavi,et al.  Methane mitigation in ruminants: from microbe to the farm scale. , 2010, Animal : an international journal of animal bioscience.

[16]  C. Martin,et al.  Milk fatty acids in dairy cows fed whole crude linseed, extruded linseed, or linseed oil, and their relationship with methane output. , 2009, Journal of dairy science.

[17]  T. Jenkins,et al.  Board-invited review: Recent advances in biohydrogenation of unsaturated fatty acids within the rumen microbial ecosystem. , 2008, Journal of animal science.

[18]  R C Boston,et al.  Kinetics of ruminal lipolysis of triacylglycerol and biohydrogenation of long-chain fatty acids: new insights from old data. , 2008, Journal of dairy science.

[19]  R. Boston,et al.  Milk fatty acids. I. Variation in the concentration of individual fatty acids in bovine milk. , 2007, Journal of dairy science.

[20]  K. Kalscheur,et al.  Effect of dietary forage concentration and buffer addition on duodenal flow of trans-C18:1 fatty acids and milk fat production in dairy cows. , 1997, Journal of dairy science.

[21]  M. Poore,et al.  Dry Matter, Crude Protein, and Starch Degradability of Five Cereal Grains , 1990 .

[22]  H. Tyrrell,et al.  Prediction of the energy value of cow's milk. , 1965, Journal of dairy science.

[23]  L. Marett,et al.  Energy partitioning in herbage-fed dairy cows offered supplementary grain during an extended lactation. , 2013, Journal of dairy science.

[24]  D. Sauvant,et al.  Influences of diet and rumen fermentation on methane production by ruminants , 2011 .

[25]  S. Francis,et al.  Associative effects between feeds when concentrate supplements are fed to grazing dairy cows: a review of likely impacts on metabolisable energy supply , 2005 .

[26]  H. Slover,et al.  Quantitative analysis of food fatty acids by capillary gas chromatography , 1979 .