LIST OF ABBREVIATIONS 4-5 SUMMARY 5-8 LIST OF TABLES 15-16 LIST OF FIGRURES 16-17 1. INTRODUCTION 17-19 2.L ITERATURE REVIEW 19-33 2.1 Vetiver grass 19 2.2 Nitrogen metabolism in ruminant 19-21 2.2.1 Urea-N in urine and blood 21 2.3 Measurement of microbial protein supply 21-25 2.3.1 Direct method 21-24 2.3.2 Indirect method 24-25 2.4 Development of the purine derivative （PD）method 25-27 2.5 Application of PD method 27-28 2.6 Feed intake and digestibility in ruminants 28-29 2.7 Digesta flow 29-30 2.7.1 Rate of passage 29-30 2.7.2 Cr-mordanted fibre 30 2.8 Creatinine in plasma and urine 30-31 2.9 Blood metabolites 31-33 2.9.1 Insulin action and Glucose metabolism in ruminants 31 2.9.2 Non-estrified fatty acid (NEFA) 31-33 3. MATERIALS AND METHODS 33-46 3.1 Experiment I Animal Metabolic study 33-37 3.1.1 Animals 33 3.1.2 Diet treatment and design 33-34 3.1.3 Housing and Management 34-36 3.1.4 Samples collection 36-37 3.1.5 Measurement of the Rate of passage using Cr-mordanted fibre 37 3.2 Experiment II Animal Performance study 37-38 3.3 Chemical analysis 38-42 3.3.1 Urine samples 38-40 3.3.2 Feed, feed refusal and faecal samples 40-41 3.3.3 Plasma samples 41-42 3.4 Calculation 42-44 3.4.1 Apparent digestion 42-43 3.4.2 Rate of passage 43-44 3.4.3 Determination of Microbial N yield based on Purine Derivatives method 44 3.5 Statistical analysis 44-46 4. RESULTS 46-60 4.1 Experiment I Animal Metabolic study 46-57 4.1.1 Intakes, digestibility, N-balance and rate of passage 46-49 4.1.2 Urinary PD excretion 49-57 4.1.3 Blood metabolites concentration 57 4.2 Experiment II Animal Performance study 57-60 5. DISCUSSION 60-66 5.1 Experiment I Animal Metabolic study 60-64 5.1.1 Voluntary intake, whole tract digestibility 60 5.1.2 N-balance 60-61 5.1.3 Rate of passage 61-62 5.1.4 Urinary PD excretion 62-63 5.1.5 Blood metabolite concentrations 63-64 5.2 Experiment II Animal Performance study 64-66 6. CONCLUSION 66-71 INNOVATION POINTS 71-72 ACKNOWLEDGEMENTS 72-74 REFERENCES 74-84 APPENDIX I 84-86 APPENDIX II 86-88 APPENDIX III 88-91 APPENDIX IV 91-93 APPENDIX V 93-94 APPENDIX VI 94-96 APPENDIX VII 96-98 APPENDIX VIII 98-101 APPENDIX IX 101-103 APPENDIX X 103-106 RESUME 106-107 SUPERVISOR INTRODUCTION 107-108 DECLARATION 108 |
