Luận án tiến sĩ sử dụng cây khoai mì sắn để phát triển chăn nuôi dê ở an giang v

HUE UNIVERSITY HUE UNIVERSITY OF AGRICULTURE AND FORESTRY LE THI THUY HANG UTILIZATION OF CASSAVA FORAGES FOR GOAT PRODUCTION IN AN GIANG PROVINCE, VIETNAM DOCTOR OF PHILOSOPHY IN ANIMAL SCIENCES HUE, 2020 HUE UNIVERSITY HUE UNIVERSITY OF AGRICULTURE AND FORESTRY LE THI THUY HANG UTILIZATION OF CASSAVA FORAGES FOR GOAT PRODUCTION IN AN GIANG PROVINCE, VIETNAM SPECIALIZATION: ANIMAL SCIENCES CODE: 9620105 DOCTOR OF PHILOSOPHY IN ANIMAL SCIENCES SUPERVISOR 1: Assoc. Nguyen Xuan Ba SUPERVISOR 2: Dr. Dinh Van Dung HUE, 2020 DECLARATION 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 Journal of Livestock Research for Rural Development (LRRD) http://www.org Hue University, 2020 Le Thi Thuy Hang, PhD. Student i DEDICATION To my parents who taught me the good things in my life, my loving husband and my sons. ii ACKNOWLEDGEMENTS These studies were carried out at An Giang University, Hue University of Agricultural and Forestry, Hue University with financial support from the Mekong Basin Animal Research Network (MEKARN II) Project. I am grateful for their support for the thesis research and the scholarship for the PhD study.

I would like to express my sincere thanks to: Associate Professor Nguyen Xuan Ba, my main supervisor, for all his ideas, knowledge and experience. Thanks for unceasing support in research and social activities. He has given me invaluable support, encouragement and guidance throughout my study. His reading, editing and follow -up of this thesis are gratefully acknowledged.

Dinh Van Dung, my second supervisor, who has given me invaluable support, encouragement, criticism, excellent skilled technical assistance and guidance throughout my study. Preston, who has given me invaluable support, for valuable advice, encouragement, enthusiasm and discussions throughout the study. His reading and correcting and follow-up of this thesis from the beginning to the end have enabled me to accomplish this work successfully, especially in correction of my English. Associate Professor Le Van An, Rector of Hue University of Agriculture and Forestry for giving us the best conditions, encouragement and support during our studies in Hue.

Khieu - Borin, Regional Coordinator of Mekarn II Project “Vietnam – SAREC Sustainable Livestock Production Systems” project, for valuable advice and discussions. Associate Professor Duong Nguyen Khang, Consultant of the “Vietnam – SAREC Sustainable Livestock Production Systems”, for valuable advice. Professors, Lectures and assistant lecturers in courses which I have attended during my studies for sharing their valuable knowledge. Vo Van Thang, Rector of An Giang University for giving me permission to study, facilitation and encouragement.

iii My Dean, Dr. Ho Thanh Binh, Dean of Agriculture and Natural Resources Faculty of An Giang university for giving me permission to study, facilitation and encouragement. My colleagues at the Department of Animal Husbandry and Veterinary Medicine of Agriculture and Natural Resources Faculty of An Giang University for performing the chemical analyses and sharing experiences in scientific research and social activities. My students, for help me in taking care the experiments.

To my friends in the PhD. Course, from Lao, Cambodia and Vietnam for giving me a warm and friendly atmosphere To my big family, for all their support and encouragement throughout my study. And special thanks to my husband Tran Xuan Hien, two children’s who understood my work, and shared the happiness and sadness with me, for his loving, unceasing support and patience for my whole- life study. iv ABSTRACT The aims of the study were to improve utilization cassava forage for increasing performance and reducing enteric methane emission in goat fed cassava forage restricted level of brewery grain and biochar in An Giang province, Vietnam.

There were one survey and four experiments in this study. The survey of cassava and goat systems in Tinh Bien and Tri Ton districts, An Giang province showed that there is an increasing tendency to plant cassava. At the same time there are major trends in the population of goats increasing. However, goat production systems were still extensive, exploiting natural feed resources with small herds of indigenous goats, which have small sizes and low growth rates.

Feed and feeding for goats were mainly natural grass and by-products, from crop growing, low nutrition. It is not enough feed in rainy and flooding season. Whole, cassava forage averaginge 5 tons/ha was available, but the farmers did not use them as feed for goats. The impact of different levels of urea added to cassava stems (CS) and its chemical properties was investigated (Experiment 1).

The urea treated cassava stems (UCS) (3% in DM) made good quality ensilage, with no loss in nutritive value that could be stored up to 8 weeks. An additional benefit was that the urea treatment reduced the content of HCN in the ensiled stems. Base on these results of the experiment 1, experiment determined the effect on feed intake, digestibility and N- retention in goats of supplementing the urea treated cassava stems (UCS) with fresh water spinach and biochar (Experiment 2). DM intake was increased 18% by supplementing the UCS with biochar; and by 24% by addition of water spinach.

The combined effect of biochar plus water spinach was to increase DM intake by 41%. Biochar increased daily N retention by 46% and the biological value of the absorbed N by 12%. It is thought that this major benefit from biochar arises from the role it plays as physical support for biofilms acting as habitat for diverse microbial communities working for the benefit of the host animal and thus acting as a form of prebiotic. Experiment 3 describes the addition of increasing levels of brewers’ grains (0 to 6%) in a diet of ad libitum sweet cassava forage for growing goats.

The 4% level of v brewers’ grains increased the DM intake, the apparent DM digestibility, the N retention and the biological value of the absorbed nitrogenous compounds. The methane levels in eructed gas increased with a curvilinear trend as the proportion of brewers’ grains in the diet was increased. The benefits of biochar were tested further in experiment 4. Twelve growing male goats of the Bach Thao breed, were given a basal diet of ad libitum fresh cassava forage supplemented with 4% (DM basis) of brewers’ grain.

The biochar was supplied over the range of 0 to 1.5% in diet DM. Responses in feed intake, live weight gain and feed conversion to biochar followed curvilinear trends with optimum benefits when biochar was added at 0.86% of the diet DM. By contrast, the eructed methane production was decreased linearly with level of biochar. Key word: Cassava stems, cassava forage, brewers’ grain, liveweight gain, biochar, methane emission vi TABLE OF CONTENTS DECLARATION.V TABLE OF CONTENTS.

vii LIST OF FIGURES. xii LIST OF TABLES.XIV LIST OF ABBREVIATIONS, SYMBOLS AND EQUIVALENTS. AIMS AND OBJECTIVES OF THE STUDY. THE AIMS OF THE STUDY.2 OBJECTIVES OF THE STUDY.

SIGNIFICANCE/INNOVATION OF THE DISSERTATION.3 CHAPTER 1 OVERVIEW OF RESEARCH ISSUES. GOAT PRODUCTION SYSTEMS IN AN GIANG.1 GEOGRAPHICAL LOCATION AND CLIMATE IN AN GIANG. GOAT RAISING SYSTEMS IN AN GIANG.1 Goat population and management. Feed and feeding management for goat.

OPPORTUNITIES AND CHALLENGE FOR GOAT PRODUCTION. THE DIGESTIVE SYSTEMS AND ENTERIC METHANE EMISSION IN RUMINANTS. RUMEN FERMENTATION AND METHANE PRODUCTION. Volatile fatty acids pattern.

Pathway of methane production. Manipulation in mitigation of methane production. POTENTIAL OF CASSAVA FORAGE FOR GOAT PRODUCTION. PLANT AREA AND DISTRIBUTION OF CASSAVA AND YIELD OF CASSAVA IN VIETNAM, AN GIANG.

POTENTIAL OF CASSAVA FORAGE FOR GOAT PRODUCTION. Proportion yield of parts of cassava forage. Composition of cassava forage, parts of cassava forage. Using cassava foliage for goat production.

Antinutritional factors (Tannin and HCN) of cassava forage. Reducing methods antinutrients factor in cassava foliage. IMPROVING GOAT PRODUCTION AND REduction of METHANE EMISSION PRODUCTION. IMPROVING STRATEGY GOAT PRODUCTION.

CLIMATE CHANGE AND REduction of METHANE EMISSION PRODUCTION. 29 CHAPTER 2 EVALUATION OF THE POTENTIAL OF CASSAVA forage AS FEED FOR GOATS IN AN GIANG PROVINCE, VIETNAM. MATERIALS AND METHODS. THE FOLLOWING INDICATORS WERE USED IN THE INVESTIGATION OF THE SURVEY.

DATA COLLECTION AND CALCULATION. RESULTS AND DISCUSSION. CASSAVA PRODUCTION IN AN GIANG PROVINCE. The production and yiled of cassava.

Plant area of cassava by district from 2014-2017. Yield of cassava with different of variety in An Giang. Planted area and the purposes of cassava cultivation. Evaluation of chemical composition of cassava parts.

The fresh and dry yield of cassava proportion with different variety. GOAT PRODUCTION IN AN GIANG PROVINCE. Ruminants population in An Giang from 2014- 2017. Goat farm size and purpose raising in An Giang province.

Goat prodution systems in An Giang. Feed and feeding systems. Diseases and diseases management. 56 CHAPTER 3 USING UREA TO TREAT CASSAVA STEMS AND EFFECT OF WATER SPINACH AND BIOCHAR ON FEED INTAKE, DIGESTIBILITY AND N- RETENTION IN GOATS FED UREA TREATED CASSAVA STEMS.

MATERIALS AND METHODS. RESULTS AND DISCUSSION.1 Hygienic quality of cassava stems treated by physical evaluation. Chemical compositions of cassava stems treated with difference levels of urea and stored times. Composition of the diet ingredients.

Feed intake and digestibility. 82 CHAPTER 4 EFFECT OF DIFFERENT LEVELS OF BREWERS’ GRAINS SUPLEMENTATION ON PERFORMANCE AND METHANE EMISSION OF GOATS FED CASSAVA FORAGE. MATERIALS AND METHODS. ANIMALS AND MANAGEMENT.

FEEDS AND FEEDING. DIGESTIBILITY AND N RETENTION. RUMEN GAS EMISSIONS. RESULTS AND DISCUSSION.

COMPOSITION OF DIET INGREDIENTS. FEED INTAKE AND DIGESTIBILITY. LIVE WEIGHT GAIN AND FEED EFFICIENCY. 99 CHAPTER 5 EFFECT OF BIOCHAR SUPPLEMENTATION LEVELS ON GROWTH AND METHANE EMISSIONS OF GOATS FED FRESH CASSAVA FORAGE.

MATERIALS AND METHODS. LOCATION AND DURATION. FEEDING AND MANAGEMENT. ERUCTED GAS EMISSIONS AND ANALYSIS.

RESULTS AND DISCUSSION. COMPOSITION OF DIET INGREDIENTS. GROWTH AND FEED CONVERSION. 113 CHAPTER 6 GENERAL DISCUSSION AND CONCLUSIONS.

POTENTIAL OF CASSAVA IN VIETNAM.2 EFFECT ON NUTRITIVE VALUE OF CASSAVA (MANIHOT ESCULENTA CRANTZ) STEMS OF ENSILING THEM WITH UREA.3 DIGESTIBILITY, NITROGEN BALANCE AND METHANE EMISSIONS IN GOATS FED CASSAVA FORAGE AND RESTRICTED LEVELS OF BREWERS’ GRAINS.4 EFFECT OF BIOCHAR AND WATER SPINACH ON FEED INTAKE, DIGESTIBILITY AND N-RETENTION IN GOATS FED UREA-TREATED CASSAVA STEMS. EFFECT OF BIOCHAR ON GROWTH AND METHANE EMISSIONS OF GOATS FED FRESH CASSAVA FORAGE. IMPLICATION AND FUTHER RESEARCH. 126 xi LIST OF FIGURES Figure 1.

Number of goats in An Giang from 2012 -2017. Distribution of goat by district in An Giang, 2017. Farmers buy grass from another region. Microbes needed for fermentation (Leek, 1993).

Metabolic pathways of VFA (Bergman, 1993). The reaction of methane generation. Plant area of cassava in Vietnam, 2017. Cassava plant parts.

Cassava forage parts. Freshly harvested cassava stems. Chopping into 5-10 cm lengths. Urea added at 3% of stems DM.

Chopped stems-urea are put in polyethylene bags and the air extracted. Urea-treated stems are stored for 21 days. Urea-treated stems after 21-day storage ready for feeding. The biochar was the residue from rice husks used as fuel in a gasifier stove (Olivier).

Biochar, water spinach and urea-treated cassava stems were fed in separate troughs. Supplements of water spinach and biochar increased DM intake by goats fed urea-treated cassava stems. Effect of water spinach on DM digestibility in goats fed urea-treated cassava stems with or without a supplement of biochar. Effect of biochar on DM digestibility in goats fed urea-treated cassava stems with or without a supplement of water spinach.

Effect of water spinach on N retention in goats fed urea-treated cassava stems with or without a supplement of biochar. Effect of biochar on N retention in goats fed urea-treated cassava stems with or without a supplement of water spinach. Effect of water spinach on N retention as % of digested N in goats fed urea-treated cassava stems with or without a supplement of biochar. Effect of biochar on N retention as % of digested N in goats fed urea- treated cassava stems with or without a supplement of water spinach.

Relationship between dry matter inatke and different level of brewers’ grain in goats fed cassava forage. Correlation between the differnce level of brewers’ grains and apparent digestibility of DM and CP. Relationship between different levels of brewers’ grains and rumen ammonia before and after offering new morning feed.