Lucinda Watt Thesis
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Sheep production on second generation, hardseeded annual pasture legumes fed as grazed and conserved forages in the Mediterranean- temperate environment of southern NSW Lucinda J Watt Bachelor of Animal Science (Hons. 1) (CSU, AUS) A thesis submitted to Charles Sturt University, Wagga Wagga, for the degree of Doctor of Philosophy (PhD) August 2019 CERTIFICATE OF AUTHORSHIP I hereby declare that this submission is my own work and to the best of my knowledge and belief, understand that it contains no material previously published or written by another person, nor material which to a substantial extent has been accepted for the award of any other degree or diploma at Charles Sturt University or any other educational institution, except where due acknowledgement is made in the thesis. Any contribution made to the research by colleagues with whom I have worked at Charles Sturt University or elsewhere during my candidature is fully acknowledged. I agree that this thesis be accessible for the purpose of study and research in accordance with normal conditions established by the Executive Director, Library Services, Charles Sturt University or nominee, for the care, loan and reproduction of thesis, subject to confidentiality provisions as approved by the University. ………………………….. Date: 08/08/2019 Lucinda J Watt I ACKNOWLEDGEMENTS This thesis would not have been possible without the help of some wonderful people who assisted me (whether it was big or small) in carrying out my experiments, reading and making edits on my thesis chapters, helping me further develop my knowledge and skill set, whilst providing some much needed emotional support throughout this experience. To my parents Andrew and Rhonda, I cannot thank you enough for all your help and support throughout my PhD. You were my rock through many hard times and I would be lost without you both. I am truly blessed to have the most amazing, caring and supportive parents. You both instilled me with the strength and resilience to make it to the end of this wild ride. To my fiancé Andrew (Mack), thank you for your support, especially during the writing stages of my thesis. You have been my calm in the storm and your patience and understanding has not gone unnoticed. To Simon Flinn, you were always there to lend a helping hand. I appreciate everything you have done and your friendship over the past 3 years. You deserve many more scones than my Mum could possibly bake! To Emma Hand, you are an absolute gem. Thank you for your friendship and enduring many long hours in the field and in the animal house with me. We are now professionals at running in gumboots! To James Stephens, thank you for all your help and most of all being a friend and listening ear. To my housemates Hannah and Eloise, thank you for all your support and chipping in when I needed an extra helping hand. Thank you for also looking after me after I’d had a long day. To Sue Street, thank you for your friendship over the years and all your help in my first year, particularly with rumen sampling. To all my work placement students, you were all amazing. I enjoyed working with all of you and teaching you new skills and hope I was able to encourage you to pursue careers in agricultural research. Thank you also to Jack Woods for helping me grind hundreds of feed samples. Thank you to my supervisors for your professional support and guidance throughout my PhD. To Associate Professor Gaye Krebs, I cannot thank you enough for all your help throughout my PhD and also throughout my earlier undergraduate years. Your early support and encouragement got me to where I am today. Thank you for enduring the overnight stays at the animal house - your dedication did not go unnoticed and I appreciated it enormously. Thank you also for your friendship and your late night messages when you had an epiphany relating to my research results. To my principal II supervisor Professor Michael Friend, thank you for providing me with the opportunity to complete my PhD, for making edits on my thesis and helping me to further develop my critical thinking and writing skills. Thank you also for providing professional support throughout my PhD. To John Piltz and Dr. Belinda Hackney, thank you also for your professional advice and support throughout my PhD. To Sharon Nielsen, thank you for taking me on as your first client in your new statistical consulting business. I have appreciated your professionalism, but most of all your patience when it came to all my statistical questions. Thank you to Professor Glenn Edwards, Dr. Natalka Kohut and Leanne Barnett and all other staff involved from the VCC for doing the rumen cannulation surgery of my sheep and providing me with ongoing support. To my rumen-fistulised sheep Hayman, Terry, Monkey, Houdini, Maggie, Baart, Kechovich, Charlie, Albert, Piggy, Gerald, Neggs, Squeaky and Bondy. You all showed me just how clever sheep really are. Although looking after you all 24/7 meant that I didn’t have much time for myself (or anyone else), you were all awesome and I miss you all dearly. Thank you to Richard and the team at the DPI Feed Analyses lab for helping me with my laboratory analyses and to Scott McDonald at the CSIRO Plant Industries, Canberra for assisting me with my n-alkane analyses. Thank you to Craig Rodham who provided the hays and silages for my animal house experiments and to my fellow PhD colleagues who provided support throughout and for sharing this experience with me. Thank you also to some of my dear friends Jess and Rob (and Hamish) for willingly helping last minute, on a number of occasions. A big thank you also to Meat and Livestock Australia, the Graham Centre for Agricultural Innovation and Charles Sturt University. This PhD would not have been made possible without their financial support. III TABLE OF CONTENTS CERTIFICATE OF AUTHORSHIP ................................................................... I ACKNOWLEDGEMENTS................................................................................. II TABLE OF CONTENTS.................................................................................... IV ABSTRACT ...................................................................................................... VIII GLOSSARY OF TERMS AND ABBREVIATIONS ....................................... XI LIST OF TABLES ........................................................................................... XIII LIST OF FIGURES ......................................................................................... XIX CHAPTER 1: Introduction .................................................................................. 1 CHAPTER 2: Literature review .......................................................................... 5 2.1 Pasture feedbase resources for livestock production .................................................5 2.1.1 Pasture feedbase resources for grazing livestock in an Australian context .......6 2.2 Digestion and metabolism of forage by ruminants ...................................................7 2.3 Factors affecting animal production on pastures .....................................................10 2.3.1 Voluntary feed intake .......................................................................................10 2.3.2 Forage quality ..................................................................................................13 2.3.3 Herbage biomass production and availability ..................................................15 2.3.4 Plant secondary compounds .............................................................................17 2.4 Pastures for livestock production ............................................................................22 2.5 Pastures in the southern Australian mixed farming zone ........................................24 2.5.1 Subterranean clover .........................................................................................25 2.5.2 Lucerne ............................................................................................................29 2.6 Second generation self-regenerating, hardseeded, annual pasture legumes ............33 2.6.1 Arrowleaf clover ..............................................................................................33 2.6.2 Biserrula ...........................................................................................................39 2.6.3 Bladder clover ..................................................................................................44 2.6.4 French serradella ..............................................................................................48 2.7. Conclusion..............................................................................................................51 CHAPTER 3: Lamb growth rates on second generation, hardseeded, annual legume pastures in late winter and spring ..................................................................... 53 3.1 Introduction .............................................................................................................53 3.2 Materials and Methods ............................................................................................55 3.2.1 Experimental plots ...........................................................................................55 3.2.2 Animal management ........................................................................................58 3.2.3 Animal and pasture data ..................................................................................59