luận án tiến sĩ sử dụng biochar và sắn trong chăn nuôi bò và việc giảm thải khí mê tan ở lào

HUE UNIVERSITY
HUE UNIVERSITY OF AGRICULTURE AND FORESTRY

BOUNTHAVY VONGKHAMCHANH

USES OF BIOCHAR AND CASSAVA FOR CATTLE
PRODUCTION AND METHANE REDUCTION
IN LAO PDR

DOCTOR OF PHILOSOPHY IN ANIMAL SCIENCES

HUE, 2021


HUE UNIVERSITY
HUE UNIVERSITY OF AGRICULTURE AND FORESTRY

BOUNTHAVY VONGKHAMCHANH
USES OF BIOCHAR AND CASSAVA FOR CATTLE
PRODUCTION AND METHANE REDUCTION
IN LAO PDR

SPECIALIZATION: ANIMAL SCIENCES
CODE: 9620105

DOCTOR OF PHILOSOPHY IN ANIMAL SCIENCES

SUPERVISORS:
1:

ASSOC. PROF. DR. LE VAN AN

2:

DR. DUONG THANH HAI

HUE, 2021


GUARANTEE
I hereby guarantee that scientific work in this thesis is mine. All results
described in this thesis are righteous and objective. They have been published in the
journal of Champasak Province, Lao PDR, journal of Livestock Research for Rural
Development (LRRD), JASTD, Lao PDR, and Journal of Animal Husbandry Sciences
and Technics (JAHST), Vietnam.

Hue University, 2020

Bounthavy, PhD student


DEDICATION
To my parents, my wife (Sangsavanh Niemthachit), daughter (Sangmany
Vongkhamchanh) and son (Pharkdy Vongkhamchanh).

i


ACKNOWLEDGEMENTS
I would like to express my sincere gratitude and appreciation to my major advisor,
Assoc. Prof. Le Van An, Department of Animal Husbandry, Fuculty of Animal Husbandry

and Veterinary Medicine, University of Agriculture and Forestry, Hue University for his
precious advice, guidance on thesis, encouragement, and constructive comments. My
deeply grateful and sincere gratitude is extended to my co-advisor, Duong Thanh Hai,
Ph.D., Department of Animal Husbandry, Fuculty of Animal Husbandry and Veterinary
Medicine, University of Agriculture and Forestry, Hue University for his kindness in
advising research proposal and experiment. I am grateful to all professors, teachers, and
staff of the Faculty of Animal Husbandry and Veterinary Medicine for the suggestion,
which enables me to complete my work. I would like to thanks MEKARN II project and
Hue University of Agriculture and Forestry for providing the financial support for my
study that enables me to complete this study. Finally, I am grateful to my family for their
financial support, care, and love.

I would like to express my deep gratitude to Professor. Thomas Reg Preston, for
guiding the experiments during the study and helping me to author my journal. I would
also like to extend sincere thanks to several people who facilitate, encourage, and
support the whole Ph.D. course such as Professor. Dr. Ewadle, International
Coordinator MEKARN II project; Dr. Vanthong Phengvichith, National Agriculture
and Forestry Research Institute (NAFRI), Dr. Daovy Kongmanila, National
Univerisity of Lao PDR; Dr. Kieu Borin, MEKARN II regional coordinator; Dr. Ngo
Tung Duc, the Head of Education Department, Hue University of Agriculture and
Forestry. Warm thanks are extended to my Ph.D. classmates from the three countries:
Laos, Vietnam, and Cambodia, for sharing the culture, friendship, and creating a warm
atmosphere throughout the Ph.D. course.

ii


ABSTRACTS
Cattle are regarded as one ruminant of livestock that is expressed the
importance for smallholder and account are more than 50% of cash income in Laos.

However, barriers to cattle production are mainly limitation of feed qualities and
quantities, and methane emission by enteric fermentation where consider as one source
of greenhouse gases. Therefore, these studies aimed to evaluate the utilization of
cassava supplied by biochar to mitigate methane production in an In vitro rumen
incubation and incorporated with the diets for fattening local yellow cattle.
Chapter 2 (experiment 1)
The rice straw and cassava leaf meal were used as substrate. Urea was used as a
source of NPN and protein. Gas production and methane in the gas were measured
over successive 6 h intervals for 24 h, after which the residual dry matter (DM) in the
substrate was determined by filtration. During the fermentation intervals (18 – 24 h)
there were significant differences in gas production between two substrates, rice straw
(276.67 ml) and cassava leaf meal (515 ml) (p<0.05). The levels of biochar (0, 1 and
2%) were no effect in gas production of the substrates, in contrast, biochar can be
reduced methane as well as 21.292, 20.417 and 19.667% respectively (p<0.05) but
between 1 and 2% of biochar were not shown any difference in decreasing the
methane production. The cassava leaf meal (78.479%) was digested significantly
higher than rice straw (70.139%). Biochar did not affect the proportion of DM
mineralized and digestibility after 24 h but reduced the production of methane per unit
DM mineralized.
Chapter 3 (experiment 2)
Dried, ensiled and fresh cassava roots were used as an energy substrate. Urea
and cassava leaf meal were used as sources of NPN and protein. Gas production and
methane in the gas were measured over successive 6 h intervals for 24 h, after which
the residual dry matter (DM) in the substrate was determined by filtration. There were
no differences in gas production among the cassava root treatments during any of the
fermentation intervals. By contrast, methane percent in the gas was lowest in the fresh
root and highest in the dried root, with intermediate values for the ensiled root. The
total DM mineralized after 24 h fermentation was not affected by root processing. Gas
production tended to be reduced (p=0.07) by biochar for the 18-24 h interval but was
not affected at the earlier intervals. The methane concentration in the gas was reduced

by biochar in the 18-24 h fermentation interval, but there was no effect for
fermentation intervals of 0-6, 6-12 and 12-18 h. Biochar did not affect the proportion
of DM mineralized after 24 h but reduced the production of methane per unit DM
mineralized.
iii


Chapter 4 (experiment 3)
Twelve local yellow cattle with an initial live weight of 90 – 105 kg were used
to evaluate the efficacies of fresh cassava root incorporated with biochar. The
experimental design was arranged in a completely randomized design (CRD) with
three replications of each treatment. The factors were different levels of fresh cassava
root (CTL, 10, 20, and 30%) with 1% biochar in diet DM. The experiment was carried
out for 84 days with an extra 14 days for adaptation to the pens and diets. Fresh
cassava root (FC) was offered as a basal diet supplemented with urea, elephant grass,
and rice straw. The addition of fresh cassava root by different levels was not shown
any effects in feed intake but when increased the level of fresh cassava root as 30%
incorporated with 1% biochar of diet DM found the cattle were displayed significant
growth rate as high as 252.4 g/d (p<0.05).
Chapter 5 (experiment 4)
In a 56-day experiment with 6 local yellow cattle fed ensiled cassava root-urea,
brewers‘ grains and rice straw, there were indications (p=0.08) that after an initial 4week adaptation to the diet, the cattle were growing faster when 1% of biochar
(derived from rice husk) was incorporated in the diet was 0.635 of LW gain, kg/d.
Chapter 6 (experiment 5)
Ensiled cassava root incorporates different levels of dry cassava leaf that is used
as a source of bypass protein for fattening local yellow cattle in Lao PDR, nine local
yellow cattle with an initial live weight of 90 – 100 kg live weight (LW) were used in
this study. The experimental design was arranged in a completely randomized design
(CRD) with three replications of each treatment. The factors were different levels of
dried cassava foliage (CTL, 25, and 50% of total diet DM). The experiment was

carried out for 14 days for adaptation to the pens and diets. Ensiled cassava root was
offered as a basal diet supplemented with rice straw and mineral block, and adding
dried cassava foliage by different levels. The results indicated that the increase of dried
cassava foliage levels was displayed the effects in feed conversion rate (FCR) (p<0.05)
and when increased the level of dried cassava foliage at 50% of total diet DM
incorporated with the diet DM found the cattle were presented significant growth rate
as high as 0.304 kg/d of ADG (p<0.05).
From experimental results can conclude that 1% biochar incorporated with
fresh or ensiled cassava root can be reduced methane emission in an In vitro rumen
fermentation. 1% biochar (derived from rice husk) incorporated with ensiled cassava
root, urea, brewers‘ grains and rice straw there were positive indications to increase the
growth rate of cattle and by-product from cassava production (dried cassava foliage)
was indicated the benefit of utilization for fattening cattle.
Keywords: Greenhouse gases, HCN, fresh cassava root, cassava leaves, diets
iv


TABLE OF CONTENTS
GUARANTEE........................................................................................................................................... iii
DEDICATION.............................................................................................................................................. i
ACKNOWLEDGEMENTS................................................................................................................... ii
ABSTRACTS............................................................................................................................................. iii
LIST OF FIGURES................................................................................................................................ xii
LIST OF TABLES................................................................................................................................. xiii
LIST OF ABBREVIATIONS, SYMBOLS AND EQUIVALENTS................................... xvi
INTRODUCTION..................................................................................................................................... 1
1. PROBLEM STATEMENT................................................................................................................ 1
2. AIMS AND OBJECTIVES OF THE STUDY........................................................................... 3
2.1 AIMS OF THE STUDY................................................................................................................... 3
2.2. OBJECTIVES OF THE STUDY................................................................................................ 3

3. RESEARCH HYPOTHESES........................................................................................................... 4
4. SIGNIFICANT/INNOVATION OF THE DISSERTATION................................................ 4
5. REFERENCES....................................................................................................................................... 4
CHAPTER 1. LITERATURE REVIEW........................................................................................... 9
1. CATTLE POPULATION AND PRODUCTION IN LAO PDR......................................... 9
1.1. THE ROLE OF CATTLE............................................................................................................... 9
1.2. CATTLE POPULATION................................................................................................................ 9
1.3. GENERAL CHARACTERISTIC OF HOUSEHOLD S‘ CATTLE RAISING......12
1.4. CATTLE PRODUCTION............................................................................................................ 12
1.4.1. BREEDS AND BREEDING................................................................................................... 12
1.4.2. Cattle meat consumption.......................................................................................................... 13
1.4.3. Cattle production system.......................................................................................................... 14
1.5. INFECTIOUS DISEASES OF CATTLE............................................................................... 16
1.6. MARKET SYSTEM OF CATTLE.......................................................................................... 17
1.7. OPPORTUNITIES AND CONSTRAINS OF CATTLE PRODUCTION................19
1.7.1. Potentials of cattle production................................................................................................ 19
1.7.2. Constrains of cattle production.............................................................................................. 19
v


2. LOCAL FEED AND FEEDING................................................................................................... 20
2.1. SITUATION OF FEED RESOURCES.................................................................................. 20
2.2. IMPORTANCE OF BY-PRODUCT........................................................................................ 20
2.3. BY-PRODUCT FROM INDUSTRIES................................................................................... 21
2.3.1. Cassava pulp.................................................................................................................................. 21
2.3.2. Brewers‘ grain.............................................................................................................................. 22
2.3.3. Rice distillers‘ by-product........................................................................................................ 23
2.3.4. Molasses.......................................................................................................................................... 23
2.4. BY-PRODUCT FROM AGRICULTURE............................................................................. 24
2.4.1. Agricultural by-product properties........................................................................................ 24

2.4.2. Straw from cereal crop.............................................................................................................. 24
2.4.3. By-product from cassava production................................................................................... 25
2.5. UTILIZATION OF BY-PRODUCT FOR RUMINANT.................................................. 25
2.6. FEEDING THE RUMEN MICROBES.................................................................................. 26
2.6.1. Multi-nutrient blocks.................................................................................................................. 27
2.6.2. Ammoniation................................................................................................................................. 27
3. GREENHOUSE GAS FROM AGRICULTURE AND MITIGATING WAYS ...........27
3.1. GREENHOUSE GAS FROM AGRICULTURE................................................................ 27
3.2. THE LIVESTOCK SECTOR..................................................................................................... 28
3.3. GREENHOUSE GAS MITIGATION FROM AGRICULTURE.................................. 29
3.4. LIVESTOCK AND MANURE MANAGEMENT............................................................ 30
3.5. CONSEQUENCES OF GLOBAL WARMING.................................................................. 30
3.6. CLIMATE AND NATURAL DISASTERS IN LAO PDR............................................. 31
3.7. GREENHOUSE GASES EMISSION FROM LIVESTOCK IN LAO PDR...........32
4. BIOCHAR............................................................................................................................................. 32
4.1. PRODUCTION OF BIOCHAR................................................................................................ 32
4.2. THE INFLUENCE OF BIOCHAR FOR MITIGATION OF GREENHOUSE
GAS EFFECT........................................................................................................................................... 34
4.3. MECHANISM OF BIOCHAR ON METHANE PRODUCTION IN THE
RUMEN....................................................................................................................................................... 34
vi


5. CASSAVA (MANIHOT ESCULENTA, CRANTZ)................................................................ 35
5.1. GOVERNMENT STRATEGIES.............................................................................................. 35
5.2. YIELD AND AVAILABILITY.................................................................................................. 35
5.3. NUTRITIVE VALUE.................................................................................................................... 36
5.4. CONSTRAINTS OF USING CASSAVA.............................................................................. 45
5.5. THE EFFECTS OF HCN FOR ANIMALS.......................................................................... 45
5.6. BARRIERS OF CASSAVA PRODUCTION IN LAOS................................................... 46

6. THE RELATED STUDIES ON USING BIOCHAR FOR GROWING CATTLE .. 47

REFERENCES......................................................................................................................................... 48
CHAPTER 2: EFFECT OF BIOCHAR LEVELS IN DRIED CASSAVA FOLIAGE
AND RICE STRAW AS SUBSTRATES ON IN VITRO METHANE PRODUCTION
58
ABSTRACT............................................................................................................................................... 58
I. INTRODUCTION............................................................................................................................... 58
II. MATERIALS AND METHODS.................................................................................................. 59
Location and duration............................................................................................................................. 59
Treatments and experimental design................................................................................................ 59
Substrates.................................................................................................................................................... 59
Source of biochar..................................................................................................................................... 59
The In vitro incubation system............................................................................................................ 60
Experimental procedure......................................................................................................................... 61
Data collection and measurements.................................................................................................... 62
Chemical analyses................................................................................................................................... 62
Statistical analysis.................................................................................................................................... 62
III. RESULTS............................................................................................................................................ 62
Gas and methane (CH4) production.................................................................................................. 63
Digestibility................................................................................................................................................ 64
IV. DISCUSSION.................................................................................................................................... 65
V. CONCLUSION................................................................................................................................... 67
VI. ACKNOWLEDGEMENT............................................................................................................ 67
vii


REFERENCES......................................................................................................................................... 67
CHAPTER 3: EFFECT OF PROCESSED CASSAVA ROOTS AND BIOCHAR ON
IN VITRO METHANE PRODUCTION BY USING RUMEN FLUID OF LOCAL

YELLOW CATTLE................................................................................................................................ 72
ABSTRACT............................................................................................................................................... 72
I. INTRODUCTION............................................................................................................................... 72
II. MATERIALS AND METHODS.................................................................................................. 73
Location....................................................................................................................................................... 73
Treatments and experimental design................................................................................................ 73
Energy source............................................................................................................................................ 73
Biochar source........................................................................................................................................... 74
The In vitro incubation system............................................................................................................ 74
Experimental procedure......................................................................................................................... 75
Data collection and measurements.................................................................................................... 76
Chemical analyses................................................................................................................................... 76
Statistical analysis.................................................................................................................................... 76
III. RESULTS............................................................................................................................................ 77
Gas and methane (CH4) production.................................................................................................. 77
Digestibility................................................................................................................................................ 79
IV. DISCUSSIONS................................................................................................................................. 80
V. CONCLUSIONS................................................................................................................................ 81
VI. ACKNOWLEDGEMENTS......................................................................................................... 81
REFERENCES......................................................................................................................................... 81
CHAPTER 4: EFFECT OF DIFFERENT LEVELS OF FRESH CASSAVA ROOT
ON GROWTH PERFORMANCE OF LOCAL YELLOW CATTLE IN LAO PDR .. 84
ABSTRACT............................................................................................................................................... 84
I. INTRODUCTION............................................................................................................................... 84
II. MATERIALS AND METHODS.................................................................................................. 85
Location and duration............................................................................................................................. 85
Treatments and experimental design................................................................................................ 85
viii

Feeds and feeding system..................................................................................................................... 86
Feeding management.............................................................................................................................. 86
Data collection.......................................................................................................................................... 87
Chemical analysis.................................................................................................................................... 87
Statistical analysis.................................................................................................................................... 87
III. RESULTS............................................................................................................................................ 87
Feed intake.................................................................................................................................................. 88
Growth and feed conversion................................................................................................................ 88
IV. DISCUSSION.................................................................................................................................... 89
V. CONCLUSIONS................................................................................................................................ 90
VI. ACKNOWLEDGEMENTS......................................................................................................... 91
REFERENCES......................................................................................................................................... 91
CHAPTER 5: EFFECT OF BIOCHAR IN ENSILED CASSAVA ROOTS, FRESH
BREWERS' GRAINS AND RICE STRAW DIETS ON GROWTH PERFORMANCE
OF LOCAL YELLOW CATTLE IN LAO PDR.......................................................................... 95
ABSTRACT............................................................................................................................................... 95
I. INTRODUCTION............................................................................................................................... 95
II. MATERIALS AND METHODS.................................................................................................. 96
Location and duration............................................................................................................................. 96
Treatments and experimental design................................................................................................ 96
Feeds and feeding system..................................................................................................................... 96
Feeding management.............................................................................................................................. 96
Data collection.......................................................................................................................................... 97
Chemical analysis.................................................................................................................................... 97
Statistical analysis.................................................................................................................................... 97
III. Results................................................................................................................................................... 97
Feed intake.................................................................................................................................................. 97
IV. DISCUSSION.................................................................................................................................... 99
V. CONCLUSIONS.............................................................................................................................. 100
VI. ACKNOWLEDGEMENTS....................................................................................................... 100

ix


REFERENCES....................................................................................................................................... 100
CHAPTER 6: EFFECT OF DIFFERENT LEVELS OF DRIED CASSAVA FOLIAGE
INCORPORATED WITH ENSILED CASSAVA ROOT ON GROWTH
PERFORMANCE OF LOCAL YELLOW CATTLE IN LAO PDR................................. 104
ABSTRACT............................................................................................................................................ 104
I. INTRODUCTION............................................................................................................................ 104
II. MATERIALS AND METHODS............................................................................................... 105
Location and duration.......................................................................................................................... 105
Animals and housing............................................................................................................................ 106
Treatments and experimental design.............................................................................................. 106
Feeding and management................................................................................................................... 106
Data collection and measurements................................................................................................. 107
Chemical analysis.................................................................................................................................. 107
Statistical analysis................................................................................................................................. 107
III. RESULTS......................................................................................................................................... 107
Chemical composition of feeds........................................................................................................ 107
Feed intake............................................................................................................................................... 108
Growth rate.............................................................................................................................................. 108
IV. DISCUSSIONS............................................................................................................................... 110
V. CONCLUSIONS.............................................................................................................................. 110
VI. ACKNOWLEDGEMENTS....................................................................................................... 111
REFERENCES....................................................................................................................................... 111
CHAPTER 7: GENERAL DISCUSSION AND CONCLUSIONS................................... 114
1. GENERAL DISCUSSION........................................................................................................... 114
1.1. UTILIZATION OF BIOCHAR............................................................................................... 114
Mitigation of methane production.................................................................................................. 114
Improving animal productions......................................................................................................... 115

1.2. UTILIZATION OF CASSAVA FOR MITIGATING METHANE EMISSION
AND GROWTH PERFORMANCE OF CATTLE.................................................................. 116
1.3. UTILIZATION OF BREWERS‘ GRAINS INCORPORATE WITH BIOCHAR
FOR FATTENING CATTLE............................................................................................................ 117
x


2. CONCLUSIONS.............................................................................................................................. 118
3. IMPLICATION AND FURTHER RESEARCH.................................................................. 119
REFERENCES....................................................................................................................................... 119
PUBLICATIONS LIST....................................................................................................................... 125

xi


LIST OF FIGURES
Table 1. Number of Livestock and Density by Province and Region.................................. 10
Table 2. Cattle herd sizes or percentage of cattle holdings in the whole country ...........11
Table 3. Statistics of meat consumption in the first six months 2017................................. 13
Table 4. Diseases of livestock in South East Asia of highest rank according to their
impact on the poor and their status in the Lao PDR................................................................... 17
Table 5. The export and import of livestock in 20017............................................................... 18
Table 6. Greenhouse gasses from livestock in Lao PDR 2016.............................................. 32
Table 7. Chemical compositions of cassava.................................................................................. 44
Table 8. The ingredients and quantities use (g DM) in the In vitro fermentation ...........60
Table 9. Ingredients of the buffer solution..................................................................................... 61
Table 10. Chemical composition of substrates............................................................................. 63
Table 11. Mean values of gas production, percent of methane in the gas, methane (ml),
DM mineralized, and methane per unit of DM mineralized for different processing of
cassava root and supplementation with biochar........................................................................... 64

Table 12. The crude protein (% CP in DM) in the ingredients and quantities used (g
DM) in the fermentation....................................................................................................................... 75
Table 13. The ingredients of the buffer solution Tilly and Terry (1963)............................76
Table 14. Mean values of gas production, percent of methane in the gas, methane (ml),
DM mineralized, and methane per unit of DM mineralized for different processing of
cassava root and supplementation with biochar........................................................................... 78
Table 15. The feed formula as treatments and approximate crude protein content........86
Table 16. Chemical composition (CP is crude protein) of diet ingredients (% DM
basis, except for DM which is on % fresh basis)......................................................................... 87
Table 17. Mean values for intake of diet components (kg DM) during the 84-day trial
88
Table 18. Mean values for live weight, DM intake and feed conversion for local
Yellow cattle fed fresh cassava root, urea, elephant grass and rice straw with and 1%
biochar......................................................................................................................................................... 88
Table 19. Chemical composition (CP is crude protein) of diet ingredients (% DM
basis, except for DM which is on % fresh basis)......................................................................... 97
xii


Table 20. Mean values for intake of diet components (kg DM) during the 56-day trial
98
Table 21. Mean values for live weight, DM intake and feed conversion for local
Yellow cattle fed ensiled cassava root-urea, brewers‘ grains and rice straw with and
without biochar......................................................................................................................................... 99
Table 22. The feed formula as treatments (kg, DM)................................................................ 106
Table 23. Chemical compositions of experimental diets (DM)........................................... 108
Table 24. Mean values for intake of diet components............................................................. 108
Table 25. Mean values for growth performance........................................................................ 109

xiii

LIST OF TABLES
Figure 1. Beef cattle number 2017 by province and region (Thousand head).................11
Figure 2. Population of cattle and buffalo during 2004-2016................................................. 11
Figure 3. Age-sex structure of cattle................................................................................................ 12
Figure 4. The increasing of meat price............................................................................................ 18
Figure 5. Estimated GHG emissions from the global agriculture industry (percentage)
28
Figure 6. Methane production from ruminant.............................................................................. 29
Figure 7. Biochar characteristic........................................................................................................ 33
Figure 8. Biochar production system............................................................................................... 33
Figure 9. the additive and substrates................................................................................................ 60
Figure 10. The step label of 40 ml of In vitro incubation to indicate the amount of gas
production.................................................................................................................................................. 61
Figure 11. In vitro incubation system as each bottle incubated at 38°C.............................61
Figure 12. Methane concentration was measured by Crowcon infra-red analyser
(Crowcon Instruments Ltd, UK)........................................................................................................ 62
Figure 13. The effect of biochar on digestibility and methane production per unit
substrate mineralized from cassava leaf and rice straw............................................................ 65
Figure 14. Substrates used in an In vitro rumen incubation.................................................... 74
Figure 15. Rice husks were carbonized in an ―updraft‖ stove produce biochar............75
Figure 16. Gas production in an In vitro rumen incubation.................................................... 76
Figure 17. Measurement of methane by Crowcon infra-red................................................... 76
Figure 18. Methane concentration in the gas was reduced when the energy substrate
was fresh rather than ensiled or dried cassava root.................................................................... 79
Figure 19. The effect of biochar on digestibility and methane production per unit
substrate mineralized from dried, ensiled and fresh cassava root......................................... 80
Figure 20. Chopped fresh cassava root........................................................................................... 87
Figure 21. Preparing mineral mixture for cattle........................................................................... 87

Figure 22. Trends in live weight of the cattle over the 84 days of the experiment
according to the treatment of different levels of fresh cassava root with 1% biochar
additive........................................................................................................................................................ 89
xiv


Figure 23. Live weight gain over successive 84-day periods of local Yellow cattle fed
fresh cassava root, urea, and rice straw with 1% biochar in the diet ............................
Figure 24. Producing biochar from rice husk in a gasifier stove (from Thuy Hang et al
2018) .............................................................................................................................. 95

Figure 25. Trends in live weight of the cattle over the 56 days of the experiment
according to the treatment with or without biochar additive .........................................

Figure 26. Live weight gain over successive 28-day periods of local Yellow cattle fed
ensiled cassava root-urea, brewers‘ grains and rice straw with and without 1% biochar
in the diet
......................................
Figure 27.

Ensiled cassava root ....

Figure 28.

Dried cassava foliage ..

Figure 29. Average daily gain (ADG/kg) of local yellow cattle fed different levels of
dried cassava foliage ....................................................................................................
Figure 30.

Growth rate of local y

Figure 31.

Biochar surface area .

e

xv


LIST OF ABBREVIATIONS, SYMBOLS AND EQUIVALENTS
%

Percentage
i.e
m
m2
km2
et al.
ha
t
g

p

Probability

Pg Petagrams
°C

kg
USD
DM
NDF
ADF
CP
SEM
OM
FCR
USD

xvi

LW


GHG
CH4
N2O
CO2
CFC
AM
NPN
m
ADB
GDP

xvii

INTRODUCTION
1. PROBLEM STATEMENT
Livestock is declared to be an important component of smallholder farms In
Laos. Trades of livestock account are more than 50% of cash income and over 95% of
livestock is commonly produced by smallholders. Cattle are regarded as one
component of livestock that is expressed the importance for smallholder and it is
mainly related to the Yellow Cattle and adapted to the environment as well, small
body, agile, hardy, good reproductive rates, and it has few calving problems. The
bodyweight of local yellow cattle is up to 350 kg for males, 250 kg for females
(Werner et al. 2002). Cattle production can ameliorate livelihood by providing several
productions such as meat, traditional ceremonies, draught power, transportation, and
manure (Phanthavong and Wanapat 2004). Cattle are presented in all provinces in Lao
PDR which the total number of cattle is about 1,827,800 heads. The highest population
of cattle is in Savannakhet province (central region) accounting for 24% follows by
Champassak, Saravan (southern region) and Vientiane (central region) (DOPF 2017).
Cassava (Manihot esculenta Crantz) is widely cultivated throughout the country
by lowland and upland farmers due to the high demand for starch export. Its‘ byproducts are mainly foliage and pulp. Cassava root can be processed in form of chips,
pellets and ensilages, it is a good source of soluble carbohydrate as high as about 88%
of fresh and 76% dry, and its‘ leaves can be used as ensilage and dried in order feed
supplementation (FAO 2017). Earlier studies of Binh et al. (2018) postulated HCN
concentration in cassava leaves can be reduced methane production in In vitro rumen
incubation by decreasing the amount of methanogenesis. Nevertheless, the potential
disadvantages of fresh cassava root are suddenly rotten, low protein content, and hydro
cyanide (mainly presents in the root tissues). Anyway, based on the cassava root
processing can be overcome as well as to conserve the quality, in which the numbers
of hydro cyanide in cassava root can be reduced by either sun-drying or ensiling.
Cassava processing has displayed the alternative ways to preserve the qualities of
cassava root, especially in the dry season that feed is not available and rainy season
that sun drying is difficult which may cause the low quality of cassava root production
by several contaminations of Aspergillus that relates aflatoxin (Loc et al. 1997).

Rice straw is regarded as a by-product of rice production which is widely has
found in several regions in Southeast Asia even Laos, it is the main feed source for
ruminants in both rainy and dry season when natural grasses are in short supply. The
characterization of rice straw is contained high fiber level (39-53% ADF) and nutrient
deficiencies such as protein (2 to 4% crude protein), vitamins, minerals, and soluble
carbohydrates. Around 98% of silica is presented in rice straw so the digestibility of
ruminants is low, the performance of which ranging from 41- 59% (Sangkhom et al.
2012; McAllister et al. 1994).
1


Elephant grass (Pennisetum purpureum Schum.) can be widely cultivated in
Southeast Asia, it has high yield potential and good nutritive value (Rusdy 2016). This
grass is adapted to a wide range of soil types including acidic but yield potential is
correlated to soil nutrient status, the dry matter yield is about 10 to 50 tons/ha under
the application of fertilizer (Rahetlah et al. 2014). Elephant grass has been extensively
used by farmers and companies for cattle production due to it can offer sufficiency and
good quality fodder, and the excess fodder can be conserved in form of silage to
provide adequate feed and to preserve the sufficient quality for raising the cattle
throughout the year (Mtengeti et al. 2014). The elephant grass was used for fattening
cattle by feeding as a single component of the diet was increased the live weight grain
about 111 to 260 g/day, the protein content ranges from 4.4 to 20.4% in dry matter
(DM) with the mean around 12%; the average NDF and ADF values are around 67 and
42%, respectively (Duy and Khang 2016).
As most greenhouse gases (GHG), except for methane, have a half-life of over a
hundred years, global GHG will have to peak by 2020 and drop by 75-80 per cent in
the period to 2050 to limit global warming to two degrees (The Climate Group 2008).
The total GHG emissions in 2010 were estimated to have increased by more than 6
percent, and for 2011 were estimated to have increased by 3.2 percent (The Guardian
2011; IEA 2011). Agriculture emissions of methane (CH 4) and nitrous oxide (N2O),

which account for 90 percent of total agricultural GHG emissions, grew by 17 percent
in the period 1990-2005, roughly proportional to the increase in global cereal
production volume, but about three times as fast as the productivity increase in global
cereal production (IPCC 2007a). These GHG emissions were predicted to rise by 3560 percent by 2030 in response to population growth and changing diets in developing
countries, especially in response to greater consumption of ruminant meat and dairy
products, as well as the future spread of industrial and factory farming, particularly in
developing countries (IPCC 2007b).
The main constrains of cattle production in Lao PDR are the inadequate
extension (including animal health) services with poorly trained staff, limited
knowledge among farmers of modern production techniques, High mortality rates and
poor reproductive rates from poor nutrition and disease, slow growth rates, feed
sources for cattle are mainly native grasses, legumes and tree leaves that are available
in the natural grassland and forests but it is available only in rainy season and limited
qualities, especially in the cropping season. Lao PDR is a one country that mainly
belong to agricultural production so it is considered as one major anthropogenic
contributor to climate change such as emissions of greenhouse gases from grazing
lands, cultivation and emissions of CH4 from enteric fermentation in ruminants
(methane emission from ruminant production was found 88 Gg in cattle and 3 Gg in
dairy cattle) (FAO 2018).
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Biochar is one material that is produced by carbonization of rice husks and
woods by low (350 – 600 °C), which has the potential to use as an additive feed for
improving the live weight gain and its property was investigated by several researchers
to employ as an additive feed for mitigating the methane emission from cattle by In
vitro and In vivo experiment which the results were displayed the mitigation of
methane production in the gas was ranked from 5 – 34% (Leng et al. 2012;
Phanthavong et al. 2015; Vongkhamchanh et al. 2015; Hansen et al. 2012; Winders et
al. 2019; Calvelo Pereira et al. 2014; Cabeza et al. 2018 and Saleem et al. 2018). Many

reports were evaluated the utilization of dried cassava foliage for fattening cattle such
as Phuong et al. (2012) was studied on effects of NPN source as cassava leaves on
growth performance and methane emissions in cattle found 16.2 of FCR and Tham et
al. (2008) was employed the different levels of cassava leaf meal (CLM) which the
employment of 0.75% of cassava leaf meal was able to increase the live weight gain of
cattle about 205 g/day and FCR was 16.1. Cassava root has been studied by several
researchers namely Leng et al. (2012); Inthapanya et al. (2016); Sengsouly and Preston
(2016); Sangkhom et al. (2017); Saroeun et al. (2018) which the results were indicated
that using ensiled cassava root as an energy source was able to improve the live weigth
gain of local yellow cattle. Therefore, ameliorating production and reducing methane
emissions from cattle should be a top priority since it could help to curb global
warming. Methane production can be manipulated by modifying rumen fermentation.
Increase in live weight gain results in reducing methane production per unit of gain.
2. AIMS AND OBJECTIVES OF THE STUDY

2.1 AIMS OF THE STUDY
The aims of the experiments were evaluated the efficacy of using cassava root,
leaves, and a by-product as a feed for local yellow cattle in Laos and to determine the
appropriate level of cassava and its‘ processing as a cassava-based diet, and biochar
was applied as an additive feed to improve live weight gain and reduce methane
emissions in eructed gas from the rumen fermentation.
2.2. OBJECTIVES OF THE STUDY
o To evaluate the efficacies of biochar that apply as an ingredient, the rice
straw and cassava leaf meal were used as a substrate to mitigate the methane
production from ruminants on using In vitro rumen techniques.
o To evaluate the cassava root processing incorporate with biochar to mitigate
methane production and improve digestibility in an In vitro rumen incubation.
o To determine the optimum level of fresh cassava root incorporated with 1%
biochar those were used as an energy source and additive feed for fattening local
yellow cattle.

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o To investigate the efficacies of biochar as an additive in cattle fattening diets
based on ensiled cassava roots and brewers‘ grains.
o To utilize dry cassava leaf foliage as a source of bypass protein combines
with ensiled cassava root to improve the live weight gain of local yellow cattle.
3. RESEARCH HYPOTHESES
o The efficacies of biochar can be applied as an ingredient to incorporate with
the diets for reducing methane production from cattle on using In vitro rumen
techniques.
o The processing of energy source substrates like dried, ensiled, and fresh
cassava root can be employed as energy diets incorporate with biochar to decrease
methane emission in an In vitro rumen incubation.
o Fresh cassava root can be employed as an energy source incorporate with 1%

biochar that is used as an additive feed to increase the live weight gain of local yellow
cattle.
o To obtain further evidence concerning the potential benefits from feeding
biochar as an additive in cattle fattening diets based on ensiled cassava roots and
brewers‘ grains.
o Ensiled cassava root incorporates with different levels of dry cassava leaf
foliage can be utilized as a source of bypass protein to increase the live weight gain of
local yellow cattle in Lao PDR.
4. SIGNIFICANT/INNOVATION OF THE DISSERTATION
- The inclusion of 1% biochar into a substrate of cassava and its byproduct

appeared to inhibit In vitro methane production.
- The inclusion of 1% biochar into the diet of Lao native cattle containing

cassava and its byproducts as supplements did not affect negatively the cattle
performance.
5. REFERENCES

Binh, P.L.T., Preston, T.R., Van, H.N. and Dinh, V.D., 2018. Methane
production in an In vitro rumen incubation of cassava pulp-urea with additives of
brewers‘ grain, rice wine yeast culture, yeast-fermented cassava pulp and leaves of
sweet or bitter cassava variety. Livestock Research for Rural Development. Volume
30,
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2019.
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produced from different biomass sources and at different process temperatures on
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