Feedlot Manure Management Considerations Including Anaerobic Digestion Potential and Mineral ...

157 Pages·2014·1.04 MB·English

by  Andrea K. Watson

University of Nebraska - Lincoln
DigitalCommons@University of Nebraska - Lincoln
Theses and Dissertations in Animal Science Animal Science Department
12-2014
Feedlot Manure Management Considerations
Including Anaerobic Digestion Potential and
Mineral Retention
Andrea K. Watson
University of Nebraska-Lincoln, [email protected]
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Watson, Andrea K., "Feedlot Manure Management Considerations Including Anaerobic Digestion Potential and Mineral Retention"
(2014).Theses and Dissertations in Animal Science. 96.
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FEEDLOT MANURE MANAGEMENT CONSIDERATIONS INCLUDING
ANAEROBIC DIGESTION POTENTIAL AND MINERAL RETENTION

by

Andrea K. Watson

A DISSERTATION

Presented to the Faculty of
The Graduate College at the University of Nebraska
In Partial Fulfillment of Requirements
For the Degree of Doctor of Philosophy

Major: Animal Science
(Ruminant Nutrition)
Under the Supervision of Professors Galen E. Erickson and Terry J. Klopfenstein

Lincoln, Nebraska
December, 2014
Feedlot Manure Management Considerations Including Anaerobic Digestion Potential
and Mineral Content of Manure

Andrea K. Watson, Ph.D.
University of Nebraska, 2014

Advisers: Galen E. Erickson and Terry J. Klopfenstein
Three anaerobic digestion trials were conducted to evaluate methane production
from feedlot manure. As organic matter content of manure decreased, degradation of
manure and methane production also linearly decreased (P ≤ 0.02). Quality, or organic
matter content of manure, had a greater impact on anaerobic digestion than diet (with and
without distillers grains) fed to cattle. Minerals in manure are concentrated in effluent
removed from anaerobic digesters.
Knowing mineral retention within cattle allows for more accurate calculation of
mineral excretion in manure. Three serial slaughter trials measured mineral retention in
growing and finishing cattle. During a growing phase, beef cattle gaining 1.10-1.18 kg/d
retained 6.8 g Ca, 3.9 g P, 0.24 g Mg, 1.2 g K, and 0.73 g S/100 g protein gained.
Retention of minerals during the growing phase was not affected by diet fed to cattle (P ≥
0.20). Finishing beef cattle, gaining 1.63-2.02 kg/d retained 7.9-17.3 g Ca, 3.2-6.2 g P, -
0.027-0.41 g Mg, 0.48-2.9 g K, and 0.29-1.9 g S/100 g protein gained. Retention of Mg,
K, and S during the finishing period was greater (P ≤ 0.02) for cattle grown slowly (< 0.6
kg/d) during the growing phase. Retention of minerals was also measured in Holstein
steers serially slaughtered every 28 d after 226 days on a finishing ration. Mineral
retention was not affected by addition of zilpaterol hydrochloride in the finishing ration
when retention was expressed relative to protein gain (P ≥ 0.14). Retention of Ca, P, Mg,
K, and S linearly decreased (P < 0.01) over days on feed when expressed as g/d.
Expressing retention relative to protein gain resulted in no differences across days on
feed (P ≥ 0.11) averaging 14.4 g Ca, 7.5 g P, 0.45 g Mg, 1.3 g K, and 1.0 g S/100 g
protein gained. In all trials, expressing mineral retention relative to protein gain allowed
for better comparisons of mineral retention across a range of weights and ADG.
ACKNOWLEDGEMENTS

Thank you to all who have made this journey possible and have made it a little
easier along the way. Thank you to those who took a chance and believed in me. Thank
you to those who took the time to teach me. Thank you to those who gave me
opportunities to succeed. Thank you to all who helped along the way and made this
journey not only bearable but fun. Thank you to all who have stood beside me, lifting me
up each time I fell—this is our accomplishment. This dissertation includes the work of so
many, to whom I am forever grateful.
iv

TABLE OF CONTENTS
LITERATURE REVIEW
Introduction ......................................................................................................................... 7
Microbial Community and Environment ............................................................................ 8
Microbial pathways involved in anaerobic digestion ...................................................... 9
Inhibition of anaerobic digestion................................................................................... 10
Anaerobic Digester Designs ............................................................................................. 13
Temperature and loading rate effects ............................................................................ 14
Effect of mixing ............................................................................................................ 17
Manure Collection affects Quality .................................................................................... 17
Dairy cattle manure ....................................................................................................... 18
Feedlot cattle manure .................................................................................................... 19
Enhancing manure quality ............................................................................................. 21
Methane Production and Benefits of Capture ................................................................... 21
Measuring methane production ..................................................................................... 21
Benefits of anaerobic digestion ..................................................................................... 23
Mineral Retention ............................................................................................................. 25
Mineral requirements .................................................................................................... 25
Calcium ......................................................................................................................... 27
Magnesium .................................................................................................................... 30
Phosphorus .................................................................................................................... 32
Potassium ...................................................................................................................... 35
Sulfur ............................................................................................................................. 36
Measuring Mineral Retention ........................................................................................... 37
Serial Harvest ................................................................................................................ 37
Balance Trials ................................................................................................................ 38
Comparison of Methods ................................................................................................ 39
Accuracy of NRC Recommendations ............................................................................... 41
Hypotheses ........................................................................................................................ 42
LITERATURE CITED ..................................................................................................... 45
v

ANAEROBIC DIGESTION OF FINISHING CATTLE MANURE WITH AND
WITHOUT DISTILLERS GRAINS PLUS SOLUBLES IN THE DIET
ABSTRACT ...................................................................................................................... 52
INTRODUCTION ............................................................................................................ 53
MATERIALS AND METHODS ...................................................................................... 54
Experiment 1 ................................................................................................................. 54
Experiment 2 ................................................................................................................. 57
Experiment 3 ................................................................................................................. 59
Calculations and Statistical Analysis ............................................................................ 60
RESULTS AND DISCUSSION ....................................................................................... 60
Experiment 1 ................................................................................................................. 61
Experiment 2 ................................................................................................................. 62
Experiment 3 ................................................................................................................. 62
Comparison of Experiments .......................................................................................... 63
Effects of Manure Quality ............................................................................................. 66
CONCLUSION ................................................................................................................. 68
LITERATURE CITED ..................................................................................................... 69
MINERAL RETENTION OF GROWING AND FINISHING BEEF CATTLE ACROSS
DIFFERENT PRODUCTION SYSTEMS
ABSTRACT ...................................................................................................................... 83
INTRODUCTION ............................................................................................................ 84
MATERIALS AND METHODS ...................................................................................... 85
Exp. 1 – Winter Grazing ............................................................................................... 86
Exp. 2 – Growing Programs .......................................................................................... 88
Calculations and Statistical Analysis ............................................................................ 89
RESULTS ......................................................................................................................... 91
DISCUSSION ................................................................................................................... 96
Calculating Mineral Requirements................................................................................ 98
Reporting Mineral Requirements ................................................................................ 103
LITERATURE CITED ................................................................................................... 104
vi

MINERAL COMPOSITION OF SERIALLY SLAUGHTERED HOLSTEIN STEERS
SUPPLEMENTED WITH ZILPATEROL HYDROCHLORIDE
ABSTRACT .................................................................................................................... 119
INTRODUCTION .......................................................................................................... 120
MATERIALS AND METHODS .................................................................................... 121
Serial Harvest and Sample Analysis ........................................................................... 122
Calculations and Statistical Analysis .......................................................................... 124
RESULTS AND DISCUSSION ..................................................................................... 126
Tissue Composition ..................................................................................................... 126
Mineral Retention ........................................................................................................ 127
Mineral Retention Procedures and Calculations ......................................................... 131
Mineral Requirements ................................................................................................. 137
LITERATURE CITED ................................................................................................... 140
7

CHAPTER 1
LITERATURE REVIEW
Introduction
Management of feedlot manure is becoming a larger responsibility as more
regulations are imposed to protect water, both surface and groundwater, from manure
contamination. Manure is an excellent source of minerals and organic matter, and is an
excellent fertilizer for crop production when appropriately applied to crop fields. In order
to apply manure in a sustainable way to meet crop nutrient requirements, it is necessary
to know the mineral content of manure. Nutrient content of manure is typically
calculated as intake of nutrients less the amount of nutrient retained in the animal. Intake
is routinely and accurately measured. Therefore, if retention is accurate and known, then
accurate predictions of minerals in manure can be accomplished.
Anaerobic digestion of manure is an alternative to spreading raw manure onto
crop fields. Anaerobic digestion uses manure and produces methane, which is captured
as energy, and effluent, which is a mineral rich fertilizer. As organic matter is degraded
within anaerobic digesters, minerals become concentrated in the effluent, allowing for
less material to be hauled to crop fields as fertilizer. In the past, anaerobic digesters have
been used extensively in dairy and swine operations, with very little adoption by feedlot
operations. Feedlot manure is the most plentiful type of manure in Nebraska. If
anaerobic digestion is to be prevalent in Nebraska it will need to be implemented at
feedlot operations. The objective of this review is to present the basic concept of
anaerobic digestion, using cattle manure as the feeding material, and describe differences
between designs in biogas production and overall efficiency. The mineral content of
8

feedlot manure is important whether raw manure or effluent is being used as fertilizer on
crop ground. Thus, the second part of the review will focus on cattle requirements for
minerals and retention of these minerals within cattle. Procedures used to measure
mineral retention and a review of values for mineral retention from the literature are
presented.
Microbial Community and Environment
Anaerobic digestion of manure has been researched and implemented on farms
successfully for hundreds of years. Biogas was used for heating bath water in 10th
century Assyria, which is modern day Turkey and Iraq (Jemmett, 2006). Anaerobic
digestion of cattle manure was occurring in 1808 when Sir Humphry Davy determined
that methane was a component of the biogas being produced (Jemmett, 2006). Anaerobic
digestion is a proven science that is based on simple parameters, but actually designing
and running a digester is quite complex. The process of anaerobic digestion involves
anaerobic microbes breaking down organic matter into intermediate substrates that can
then be utilized by a second population of microbes and turned into biogas. Biogas is a
blend of methane and carbon dioxide with some trace amounts of ammonia, hydrogen
sulfide, and water (Franco et al., 2007). The methane that is produced can be converted
into electricity, as well as heat, thus the goal is to maximize methane production. The
basic biology behind an anaerobic digester is the same as anaerobic digestion and
methanogenesis within a ruminant animal’s digestive tract or within coral reefs in the
ocean; however, in most of these systems methane production is seen as an inefficient
process and is minimized. Within all of these systems, different intermediate substrates
are produced and utilized, countless microbes are present, but the end products are the