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Modelling the Effect of Diet Composition on Enteric Methane Emissions across Sheep, Beef Cattle and Dairy Cows

View Article: PubMed Central - PubMed

ABSTRACT

Simple summary: Enteric methane emissions produced by ruminant livestock has gained global interest due to methane being a potent greenhouse gas and ruminants being a significant source of emissions. In the absence of measurements, prediction models can facilitate the estimation of enteric methane emissions from ruminant livestock and aid investigation of mitigation options. This study developed a practical method using feed analysis information for predicting enteric methane emissions from sheep, beef cattle and dairy cows fed diets encompassing a wide range of nutrient concentrations.

Abstract: Enteric methane (CH4) is a by-product from fermentation of feed consumed by ruminants, which represents a nutritional loss and is also considered a contributor to climate change. The aim of this research was to use individual animal data from 17 published experiments that included sheep (n = 288), beef cattle (n = 71) and dairy cows (n = 284) to develop an empirical model to describe enteric CH4 emissions from both cattle and sheep, and then evaluate the model alongside equations from the literature. Data were obtained from studies in the United Kingdom (UK) and Australia, which measured enteric CH4 emissions from individual animals in calorimeters. Animals were either fed solely forage or a mixed ration of forage with a compound feed. The feed intake of sheep was restricted to a maintenance amount of 875 g of DM per day (maintenance level), whereas beef cattle and dairy cows were fed to meet their metabolizable energy (ME) requirement (i.e., production level). A linear mixed model approach was used to develop a multiple linear regression model to predict an individual animal’s CH4 yield (g CH4/kg dry matter intake) from the composition of its diet. The diet components that had significant effects on CH4 yield were digestible organic matter (DOMD), ether extract (EE) (both g/kg DM) and feeding level above maintenance intake: CH4 (g/kg DM intake) = 0.046 (±0.001) × DOMD − 0.113 (±0.023) × EE − 2.47 (±0.29) × (feeding level − 1), with concordance correlation coefficient (CCC) = 0.655 and RMSPE = 14.0%. The predictive ability of the model developed was as reliable as other models assessed from the literature. These components can be used to predict effects of diet composition on enteric CH4 yield from sheep, beef and dairy cattle from feed analysis information.

No MeSH data available.


A box and whisker diagram showing the minimum, lower quartile, mean (- - -), median, upper quartile and maximum for observed minus predicted CH4 yield (g/kg dry matter (DM) intake) across sheep, beef cattle and dairy cow data.
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animals-06-00054-f003: A box and whisker diagram showing the minimum, lower quartile, mean (- - -), median, upper quartile and maximum for observed minus predicted CH4 yield (g/kg dry matter (DM) intake) across sheep, beef cattle and dairy cow data.

Mentions: After accounting for the significant fixed effects of DOMD, EE and feeding level on CH4 yield (Equation (4)) and random effects of experiments, there was still notable residual variation (difference between observed and predicted values) in CH4 emissions among cattle and sheep (Figure 3). Overall, sheep and cattle species were associated with a similar range of residual values, but beef cattle had a lower mean and median residual value compared to sheep and dairy cows.


Modelling the Effect of Diet Composition on Enteric Methane Emissions across Sheep, Beef Cattle and Dairy Cows
A box and whisker diagram showing the minimum, lower quartile, mean (- - -), median, upper quartile and maximum for observed minus predicted CH4 yield (g/kg dry matter (DM) intake) across sheep, beef cattle and dairy cow data.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5035949&req=5

animals-06-00054-f003: A box and whisker diagram showing the minimum, lower quartile, mean (- - -), median, upper quartile and maximum for observed minus predicted CH4 yield (g/kg dry matter (DM) intake) across sheep, beef cattle and dairy cow data.
Mentions: After accounting for the significant fixed effects of DOMD, EE and feeding level on CH4 yield (Equation (4)) and random effects of experiments, there was still notable residual variation (difference between observed and predicted values) in CH4 emissions among cattle and sheep (Figure 3). Overall, sheep and cattle species were associated with a similar range of residual values, but beef cattle had a lower mean and median residual value compared to sheep and dairy cows.

View Article: PubMed Central - PubMed

ABSTRACT

Simple summary: Enteric methane emissions produced by ruminant livestock has gained global interest due to methane being a potent greenhouse gas and ruminants being a significant source of emissions. In the absence of measurements, prediction models can facilitate the estimation of enteric methane emissions from ruminant livestock and aid investigation of mitigation options. This study developed a practical method using feed analysis information for predicting enteric methane emissions from sheep, beef cattle and dairy cows fed diets encompassing a wide range of nutrient concentrations.

Abstract: Enteric methane (CH4) is a by-product from fermentation of feed consumed by ruminants, which represents a nutritional loss and is also considered a contributor to climate change. The aim of this research was to use individual animal data from 17 published experiments that included sheep (n = 288), beef cattle (n = 71) and dairy cows (n = 284) to develop an empirical model to describe enteric CH4 emissions from both cattle and sheep, and then evaluate the model alongside equations from the literature. Data were obtained from studies in the United Kingdom (UK) and Australia, which measured enteric CH4 emissions from individual animals in calorimeters. Animals were either fed solely forage or a mixed ration of forage with a compound feed. The feed intake of sheep was restricted to a maintenance amount of 875 g of DM per day (maintenance level), whereas beef cattle and dairy cows were fed to meet their metabolizable energy (ME) requirement (i.e., production level). A linear mixed model approach was used to develop a multiple linear regression model to predict an individual animal’s CH4 yield (g CH4/kg dry matter intake) from the composition of its diet. The diet components that had significant effects on CH4 yield were digestible organic matter (DOMD), ether extract (EE) (both g/kg DM) and feeding level above maintenance intake: CH4 (g/kg DM intake) = 0.046 (±0.001) × DOMD − 0.113 (±0.023) × EE − 2.47 (±0.29) × (feeding level − 1), with concordance correlation coefficient (CCC) = 0.655 and RMSPE = 14.0%. The predictive ability of the model developed was as reliable as other models assessed from the literature. These components can be used to predict effects of diet composition on enteric CH4 yield from sheep, beef and dairy cattle from feed analysis information.

No MeSH data available.