Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2017 Hazard identification, diagnostic investigations, and risk communication on the subject of pine needle abortion Douglas Byron Snider Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Pathology Commons, Toxicology Commons, and the Veterinary Medicine Commons Recommended Citation Snider, Douglas Byron, "Hazard identification, diagnostic investigations, and risk communication on the subject of pine needle abortion" (2017). Graduate Theses and Dissertations. 15619. https://lib.dr.iastate.edu/etd/15619 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Hazard identification, diagnostic investigations, and risk communication on the subject of pine needle abortion by Douglas Byron Snider A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Toxicology Program of Study Committee: Steve M. Ensley, Co-major Professor Aileen F. Keating, Co-major Professor Michael J. Yaeger Jacek A. Koziel Iowa State University Ames, Iowa 2017 Copyright © Douglas Byron Snider, 2017. All rights reserved. ii DEDICATION To my loving wife, Chrissy, you gave up your access to the coast of California when returning to the Midwest. You moved in loving support of my academic pursuits so I am deeply indebted to your sacrifice. Your losses have not gone without notice. It is my hope that you will find satisfaction in the journey rather than the destination. Our sojourn in Iowa was brief. I hope our journey together will have many more sunrises and sunsets to enjoy. With luck, we will enjoy many of them overlooking the ocean once again. I am so thankful to you for such joy in my life and I hope to repay the favor. To my beautiful children, Douglas Asher and Maeven Sparrow, you two have endured my absence in 85 preparation of this thesis and preparation for board examination. Your smiles truly light up any room! A tear fills my eye every morning as I drive away while you waive good- bye. Your hugs are missed throughout the day. When I return in the evening, your embraces are so strong. Then you beg me to play. How can I resist? The sound of your laughter and pitter-patter of little feet reminds me that I have returned to a happy home. To my parents, you have continually challenged me. You gave me progressive steps of responsibility to strengthen me throughout childhood. I am indebted to you as well for providing loving guidance. You have always answered when I call. You have always listened when I speak. Though we may not have the answers, you have been patient with me. To my siblings Tracy, Scott, and Debra, your loving support, protection, and enjoyable contests of sibling competition have been enjoyed throughout the years though a distant memory now. Now that we have grown, I miss you more and more. We will always have our shared memories. I always enjoy looking at old pictures and reminiscing of our childhood. May you always be young and adventurous at heart. iii TABLE OF CONTENTS DEDICATION .......................................................................................................................... ii PRELUDE............................................................................................................................... vii NOMENCLATURE ................................................................................................................ ix ACKNOWLEDGEMENTS .......................................................................................................x ABSTRACT ............................................................................................................................ xii CHAPTER 1. INTRODUCTION: PINE NEEDLE ABORTION IN CATTLE .......................1 General introduction ..................................................................................................................1 Dissertation organization ...........................................................................................................4 CHAPTER 2. LITERATURE REVIEW: OVER ONE HUNDRED YEARS OF SCIENTIFIC ADVANCES ON THE TOPIC OF PINE NEEDLE ABORTION .....................7 Executive summary ....................................................................................................................8 Background ................................................................................................................................9 Economics ................................................................................................................................11 85 Principles of PNA ....................................................................................................................12 Species affected .......................................................................................................................13 Cattle ........................................................................................................................................13 Other species ............................................................................................................................14 Trees involved ..........................................................................................................................17 Etiology ....................................................................................................................................19 Determination of causative agent.............................................................................................19 Chemical analysis ....................................................................................................................19 Toxic principle .........................................................................................................................20 Assays ......................................................................................................................................22 Toxicokinetics ..........................................................................................................................23 Tripartate biotransformation ....................................................................................................23 Absorption................................................................................................................................23 Metabolism ..............................................................................................................................24 Ruminal metabolism and depot effect .....................................................................................24 Systemic metabolism ...............................................................................................................26 Adaptation of rumen and systemic metabolism .......................................................................28 Summary of rumen and systemic metabolism .........................................................................30 Distribution ..............................................................................................................................30 Excretion ..................................................................................................................................31 Toxicodynamics .......................................................................................................................31 Mechanism of action ................................................................................................................32 Hormonal changes ...................................................................................................................41 Dose response ..........................................................................................................................48 Orally administered pine needle, dose response ......................................................................48 Orally administered Extracts, dose response ...........................................................................51 Intravenously administered isocupressic acid, dose response .................................................53 Pathophysiology .......................................................................................................................54 Prior to abortion .......................................................................................................................55 Post-abortion ............................................................................................................................55 iv Other effects .............................................................................................................................57 Renal effects.............................................................................................................................57 Nutritional effects ....................................................................................................................58 Debunked theories ...................................................................................................................59