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Quantifying Impact of Diet on Enteri...
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Niu, Mutian.
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Quantifying Impact of Diet on Enteric Methane Emissions and Manure Nutrient Dynamics in Dairy Cattle.
紀錄類型:
書目-電子資源 : Monograph/item
正題名/作者:
Quantifying Impact of Diet on Enteric Methane Emissions and Manure Nutrient Dynamics in Dairy Cattle./
作者:
Niu, Mutian.
出版者:
Ann Arbor : ProQuest Dissertations & Theses, : 2017,
面頁冊數:
169 p.
附註:
Source: Dissertation Abstracts International, Volume: 79-01(E), Section: B.
Contained By:
Dissertation Abstracts International79-01B(E).
標題:
Animal sciences. -
電子資源:
http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10285802
ISBN:
9780355151848
Quantifying Impact of Diet on Enteric Methane Emissions and Manure Nutrient Dynamics in Dairy Cattle.
Niu, Mutian.
Quantifying Impact of Diet on Enteric Methane Emissions and Manure Nutrient Dynamics in Dairy Cattle.
- Ann Arbor : ProQuest Dissertations & Theses, 2017 - 169 p.
Source: Dissertation Abstracts International, Volume: 79-01(E), Section: B.
Thesis (Ph.D.)--University of California, Davis, 2017.
Global food demand is increasing with the greater population in the world, and people are at risk of hunger without climate change mitigation. Emissions of greenhouse gases (GHG) have a significant impact on climate change globally, which poses a major and growing threat to global food security. The GHG emissions from livestock account for 14.5% of global anthropogenic emission, in which, enteric methane (CH4) emissions from ruminants (mainly from beef and dairy cattle production) are shown to be the major contributors (Gerber et al., 2013). In addition, production of CH4 and nitrous oxide from manure storage, grazing, and forage production. According to 2013 estimates, dairy cattle generated approximate 13% of agricultural GHG emission through enteric CH4 production and manure management along in U.S. (USDA, 2016). Furthermore, dairy production also contributes to the release of reactive nitrogen (N) into the environment, which can have negative impacts on water quality and alter the physical structure of ecosystems, which can have cascading effects in the environment (Pardo et al., 2015). Therefore, research is required to have a further understanding in this area, in order to take proper mitigation actions. In this context, the author approached such goals through five research studies including both animal or field experiments and statistical modeling projects. A brief description of each research experiment is given as follow.
ISBN: 9780355151848Subjects--Topical Terms:
3174829
Animal sciences.
Quantifying Impact of Diet on Enteric Methane Emissions and Manure Nutrient Dynamics in Dairy Cattle.
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Global food demand is increasing with the greater population in the world, and people are at risk of hunger without climate change mitigation. Emissions of greenhouse gases (GHG) have a significant impact on climate change globally, which poses a major and growing threat to global food security. The GHG emissions from livestock account for 14.5% of global anthropogenic emission, in which, enteric methane (CH4) emissions from ruminants (mainly from beef and dairy cattle production) are shown to be the major contributors (Gerber et al., 2013). In addition, production of CH4 and nitrous oxide from manure storage, grazing, and forage production. According to 2013 estimates, dairy cattle generated approximate 13% of agricultural GHG emission through enteric CH4 production and manure management along in U.S. (USDA, 2016). Furthermore, dairy production also contributes to the release of reactive nitrogen (N) into the environment, which can have negative impacts on water quality and alter the physical structure of ecosystems, which can have cascading effects in the environment (Pardo et al., 2015). Therefore, research is required to have a further understanding in this area, in order to take proper mitigation actions. In this context, the author approached such goals through five research studies including both animal or field experiments and statistical modeling projects. A brief description of each research experiment is given as follow.
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The objective of the first experiment was to determine the effect of dietary crude protein (CP) and forage contents on enteric CH4 emissions and N excretion from dairy cows simultaneously as described in Chapter 1. In particular, the interaction between dietary CP and energy on enteric CH 4 emission and N excretion in lactating dairy cows fed a total mixed ration based on alfalfa hay was investigated. The experiment demonstrated no interactions between dietary CP and forage contents on enteric CH 4 production of dairy cows, however, CH4 production and N excretions in lactating dairy cows can be independently reduced by reducing dietary forage and dietary CP contents, respectively.
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Following the in vivo experiment, fresh fecal samples were collected directly from dairy cows. The objective of the second experiment was to quantify the impacts of dietary forage and CP levels on the excretion and prevalence of Escherichia coli O157:H7 and Listeria spp. in dairy cattle feces as describe in Chapter 2. In addition, the concentration of different pathogens over the course of a day was characterized. The experiment demonstrated that dietary forage and CP content in animal feed have the potential to influence the fecal shedding of pathogens in dairy cattle.
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Carryover from the in vivo experiment, all available manure from the sample collection periods were stored using different manure storage methods for 6 months in the third experiment as stated in Chapter 3. The objective of the experiment was to evaluate the effects of dietary mitigation strategies to reduce both enteric CH4 production and N excretion on nutrient dynamics of manures stored in common western production practices. In addition, the short-term nutrient availability and update in soil amended with manures following storage, by barley, was evaluated. Furthermore, the overall system N use efficiencies of the dietary changes were determined. Turning manures during storage reduced the loss of both C and N, compared to both slurry and static piled manures, however, the availability of the N in the turned pile treatment was less than from the static pile and slurry treatments. In addition, feeding a lower CP diet increased the system N use efficiency when accounting for losses during excretion and storage in dairy farming system.
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The fourth project is outlined in Chapter 4. In this project, we collated a global database of enteric CH4 production containing more than 5,000 lactating dairy cow records from 15 countries around the world, consequently, developed both global and regional prediction equations for CH4 production (g/d per cow), CH4 yield (g/kg dry matter intake [DMI]), and CH4 intensity (g/kg energy corrected milk [ECM]) of different complexities. We aimed to identify key predictor variables for CH4 emissions and characterize their relationships to CH4 production, yield, and intensity were identified. In addition, the trade-off between model complexity and prediction accuracy of enteric CH4 production in dairy cows was assessed. Furthermore, robust enteric CH4 inventory and mitigation options for dairy farming system were provided through the prediction modeling outcomes. The study demonstrated an increasing trend of model predictive ability for enteric CH4 production of lactating dairy cows with increasing model complexity. For enteric CH 4 production, DMI is the most important predictor variable, whereas its impact on CH4 yield and CH4 intensity is insignificant. In addition, results also indicated that the development of enteric CH 4 prediction models should be made on regional basis.
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The fifth project was a follow-up modeling project of the previous study which is outlined in Chapter 5. The objective of this project is to develop regional enteric CH4 production prediction (g/d per cow) models of multiple complexities and study the trade-off between model complexity and their predictive ability using non-parametric statistical models and to characterize the potential nonlinear relationships between predictor variables and enteric CH4 production of lactating dairy cattle. The improvement on model predictive ability on enteric CH4 production was not observed by using generalized additive mixed model compared to linear mixed effect model approach.
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