Bovine Surgery and Lameness E-Book

A. David Weaver

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 507

Veröffentlichungsjahr: 2018

Beschreibung

The revised and updated Third Edition of Bovine Surgery and Lameness offers veterinarians a concise text ideal for use in the field. 

• Offers a fully revised edition of the popular and well-respected book on bovine surgery and lameness
• Presents a practical quick-reference guide ideal for the field veterinarian
• Covers both common surgical procedures and the latest information on combating lameness
• Written by an expert team of international authors
• Includes access to a companion website offering video clips

Leseprobe

CONTENTS

Cover

Title Page

Copyright

Preface

Acknowledgements

About the Companion Website

Chapter 1: General considerations and anaesthesia

1.1 Pre-operative Assessment

1.2 Instrumentation

1.3 Asepsis

1.4 Sutures and Suturing

1.5 Restraint

1.6 Pre-medication and Sedation

1.7 General Anaesthesia

1.8 Local Analgesics

1.9 Regional Analgesia

Chapter 2: Fluid and supportive therapy

2.1 General Principles of Fluid Therapy

2.2 Shock

2.3 Hydration Status

2.4 Acid–base Status

2.5 Other Electrolytes

2.6 Oral Fluid Therapy

2.7 Intravenous Fluid Therapy

2.8 Blood Transfusions

2.9 Transfaunation

2.10 Antimicrobial Therapy

2.11 Peri-operative Analgesia

Chapter 3: Diagnostic Techniques and Procedures

3.1 Abdominocentesis

3.2 Rumenocentesis

3.3 Liver Biopsy

3.4 Bronchoalveolar Lavage (BAL)

3.5 Trans-Tracheal Aspiration

3.6 Pleurocentesis

3.7 Pericardiocentesis

3.8 Bladder Catheterisation

3.9 Coccygeal Venepuncture

Chapter 4: Head and Neck Surgery

4.1 Disbudding and Dehorning

4.2 Trephination of Frontal Sinus (for Empyema)

4.3 Entropion

4.4 Third Eyelid Flap

4.5 Eyelid Lacerations

4.6 Ocular Foreign Body

4.7 Neoplasia of Eyelids

4.8 Enucleation (Ocular Exenteration)

4.9 Insertion of a Nose Ring in a Bull

4.10 Tracheotomy

4.11 Oesophageal Obstruction (‘choke’)

Chapter 5: Abdominal Surgery

5.1 Topography

5.2 Exploratory Laparotomy (Celiotomy), Left Flank

5.3 Exploratory Laparotomy, Right Flank

5.4 Rumenotomy

Traumatic Reticulitis/Reticuloperitonits

Vagal Indigestion (Hoflund Syndrome)

5.5 Temporary Rumen Fistulation

Chronic Recurrent Rumen Tympany in Calves

Chronic Ruminal Tympany in Adult Cattle

5.6 Left Displacement of Abomasum (LDA)

5.7 Right Dilatation, Displacement and Volvulus of Abomasum (RDA)

5.8 Other Abomasal Conditions

Abomasal Impaction

Abomasal Tympany and Volvulus in Calves

Abomasal Ulceration

5.9 Caecal Dilatation and Dislocation

5.10 Intestinal Intussusception

5.11 Other forms of Intestinal Obstruction

5.12 Peritonitis

5.13 Umbilical Hernia and Abscess

5.14 Alimentary Conditions Involving Neoplasia

5.15 Anal and Rectal Atresia

5.16 Rectal Prolapse

Chapter 6: Female urinogenital surgery

6.1 Caesarean Section (Hysterotomy)

6.2 Vaginal and Cervical Prolapse

6.3 Uterine Prolapse

6.4 Perineal Laceration

6.5 Episiotomy

6.6 Ovariectomy

6.7 Bladder Eversion

Chapter 7: Teat surgery

7.1 Introduction

7.2 Obstruction of Teat Orifice, Streak Canal or Furstenberg's Rosette

7.3 Milk Stones and Teat Lumen Granuloma

7.4 Teat Base Membrane Obstruction

7.5 Traumatic Lacerations of Teat

7.6 Imperforate Teat

7.7 Incompetent Teat Sphincter

7.8 Teat Amputation

Chapter 8: Male Urinogenital Surgery

8.1 Preputial Prolapse or Eversion

8.2 Penile Haematoma

8.3 Urolithiasis

8.4 Ruptured Bladder

8.5 Prevention of Intromission

8.6 Vasectomy

8.7 Epididymectomy

8.8 Congenital Penile Abnormalities

Corkscrew Penis or Spiral Penis

Persistent Frenulum

Other Congenital Anomalies of Bovine Penis

8.9 Penile Neoplasia

Papillomatosis

Malignant Squamous Cell Carcinoma

8.10 Castration

8.11 Cryptorchidism and Ectopic Testicle

Chapter 9: Musculoskeletal Conditions and Lameness

9.1 Introduction and Welfare

9.2 Mobility (Lameness) Scoring

9.3 Functional Foot Anatomy

9.4 Main Foot Lesions: Terminology and Summary

9.5 Hoof Trimming Technique: Corrective (Therapeutic) and Preventive Trims

9.6 Therapeutic Trimming of Claw Horn Lesions

9.7 Interdigital Phlegmon (Foul of the Foot)

9.8 Digital Dermatitis

9.9 Interdigital Hyperplasia

9.10 Sole Ulcer

9.11 White Line Disease

9.12 Toe Necrosis

9.13 Vertical (Longitudinal) or Horizontal (Transverse) Wall Fissures

9.14 Fractured Pedal Bone

9.15 Punctured Sole

9.16 Heel Bulb Haematoma/Abscess

9.17 Deep Digital Sepsis

9.18 Digit Amputation

9.19 Resection of Flexor Tendon

9.20 Digit-Sparing Techniques: Curettage and Arthrodesis of Distal Interphalangeal Joint

9.21 Osteomyelitis

9.22 Infectious Arthritis (‘Joint Ill’) of Calves

9.23 Antibiotic Therapy of Bone and Joint Infections

9.24 Contracted Flexor Tendons

9.25 Tarsal and Carpal Hygroma

9.26 Patellar Luxation

Dorsal Patellar Luxation or Fixation

Lateral Patellar Luxation

Medial Patellar Luxation

9.27 Spastic Paresis

9.28 Hip Luxation

9.29 Stifle Lameness

9.30 Nerve Paralysis of Limbs

9.31 Tail Amputation

9.32 Limb Fractures

Long Bone Fractures

Physeal Separation (Salter-Harris Fracture)

Appendix

1 Further Reading

2 Abbreviations

3 Conversion Factors for Old and SI Units

Index

End User License Agreement

List of Tables

Table 1.1

Tables 1.2

Table 1.3

Table 1.4

Table 1.5

Table 1.6

Table 1.7

Table 1.8

Table 2.1

Table 2.2

Table 2.3

Table 2.4

Table 2.5

Table 3.1

Table 3.2

Table 3.3

Table 3.4

Table 5.1

Table 9.1

Table 9.2

Table 9.3

Table 9.4

Table 9.5

Table 9.6

Table 9.7

Table 9.8

List of Illustrations

Figure 1.1

Figure 1.2

Figure 1.3

Figure 1.4

Figure 1.5

Figure 1.6

Figure 1.7

Figure 1.8

Figure 1.9

Figure 1.10

Figure 1.11

Figure 1.12

Figure 1.13

Figure 1.14

Figure 1.15

Figure 1.16

Figure 2.1

Figure 2.2

Figure 3.1

Figure 3.2

Figure 3.3

Figure 3.4

Figure 3.5

Figure 4.1

Figure 4.2

Figure 4.3

Figure 4.4

Figure 4.5

Figure 4.6

Figure 4.7

Figure 4.8

Figure 4.9

Figure 4.10

Figure 4.11

Figure 5.1

Figure 5.2

Figure 5.3

Figure 5.4

Figure 5.5

Figure 5.6

Figure 5.7

Figure 5.8

Figure 5.9

Figure 5.10

Figure 5.11

Figure 5.12

Figure 5.13

Figure 5.14

Figure 5.15

Figure 5.16

Figure 5.17

Figure 5.18

Figure 5.19

Figure 5.20

Figure 5.21

Figure 5.22

Figure 5.23

Figure 5.24

Figure 5.25

Figure 5.26

Figure 5.27

Figure 6.1

Figure 6.2

Figure 6.3

Figure 6.4

Figure 6.5

Figure 6.6

Figure 6.7

Figure 7.1

Figure 7.2

Figure 7.3

Figure 7.4

Figure 7.5

Figure 8.1

Figure 8.2

Figure 8.3

Figure 8.4

Figure 8.5

Figure 8.6

Figure 8.7

Figure 8.8

Figure 8.9

Figure 8.10

Figure 8.11

Figure 8.12

Figure 8.13

Figure 8.14

Figure 8.15

Figure 9.1

Figure 9.2

Figure 9.3

Figure 9.4

Figure 9.5

Figure 9.6

Figure 9.7

Figure 9.8

Figure 9.9

Figure 9.10

Figure 9.11

Figure 9.12

Figure 9.13

Figure 9.14

Figure 9.15

Figure 9.16

Figure 9.17

Figure 9.18

Figure 9.19

Figure 9.20

Figure 9.21

Figure 9.22

Figure 9.23

Figure 9.24

Figure 9.25

Figure 9.26

Figure 9.27

Figure 9.28

Figure 9.29

Figure 9.30

Figure 9.31

Figure 9.32

Figure 9.33

Figure 9.34

Figure 9.35

Guide

Cover

Table of Contents

Begin Reading

Chapter 1

Pages

iii

iv

vii

viii

ix

x

xi

xii

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

Bovine Surgery and Lameness

Third Edition

A. David Weaver

BSc, Dr med vet, PhD, FRCVS, Dr hc (Warsaw)

Professor emeritus, College of Veterinary Medicine

University of Missouri, USA and Bearsden, Glasgow, Scotland

Owen Atkinson

BVSc, DCHP, MRCVS

Royal College of Veterinary Surgeons Specialist in Cattle Health and Production

Dairy Veterinary Consultancy Ltd, Cheshire, UK

Guy St. Jean

DMV, MS, Dipl ACVS

Professor of Surgery, Former Head, Department of Veterinary

Clinical Sciences, School of Veterinary Medicine

Ross University, St Kitts, West Indies

Adrian Steiner

Dr med vet, FVH, MS, Dr habil, Dipl ECVS, Dipl ECBHM

Professor and Head, Clinic for Ruminants, Vetsuisse-Faculty of Berne Switzerland

This edition first published 2018

© 2018 John Wiley and Sons Ltd.

Edition History

Blackwell Scientific Publications (1e, 1986); Wiley-Blackwell (2e, 2005)

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions.

The right of A. David Weaver, Owen Atkinson, Guy St. Jean, and Adrian Steiner to be identified as the authors of this work has been asserted in accordance with law.

Registered Offices

John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA

John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK

Editorial Office

9600 Garsington Road, Oxford, OX4 2DQ, UK

For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com.

Wiley also publishes its books in a variety of electronic formats and by print-on-demand. Some content that appears in standard print versions of this book may not be available in other formats.

Limit of Liability/Disclaimer of Warranty

While the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials or promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where appropriate. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages.

Library of Congress Cataloging-in-Publication Data

Names: Weaver, A. David (Anthony David), author. | Atkinson, Owen, author. | St. Jean, Guy, author. | Steiner, Adrian, 1959- author.

Title: Bovine surgery and lameness [electronic resource] / by A. David Weaver, Owen Atkinson, Guy St. Jean, Adrian Steiner.

Description: Third edition. | Hoboken, NJ : Wiley, 2018. | Includes bibliographical references and index. |

Identifiers: LCCN 2017050346 (print) | LCCN 2017055592 (ebook) | ISBN 9781119040514 (pdf) | ISBN 9781119040491 (epub) | ISBN 9781119040460 (pbk.)

Subjects: LCSH: Cattle–Surgery. | Lameness in cattle. | MESH: Cattle Diseases | Cattle–surgery | Lameness, Animal

Classification: LCC SF961 (ebook) | LCC SF961 .W43 2018 (print) | NLM SF 961 | DDC 636.2/0897–dc23

LC record available at https://lccn.loc.gov/2017050346

Cover Design: Wiley

Cover Images: Courtesy of Owen Atkinson

Preface

Having discarded the prefaces of the first two editions of “Bovine Surgery and Lameness”, the third edition has some changes in its format. However, the emphasis of this paperback, designed to be available in the car for easy access (rather than gathering dust on the practice bookshelf), has the same aims as its predecessors. It should give the “nuts and bolts” or “how to…” of the previous editions. It has an additional author, Owen Atkinson, a dairy consultant veterinarian who has over twenty years experience of intensive dairy cattle practice in England. Owen has completely rewritten the lameness chapter, and has also reorganised the introductory sections to give greater emphasis to supportive therapy and certain selected diagnostic procedures.

Other changes include expansion of the surgical management of abomasal disorders to include laparoscopic techniques introduced into veterinary medicine over the last 15 years. These techniques have been clarified by greater use of line drawings, that were appreciated in the second edition. Three such line drawings illustrate the front cover.

As well as ethical considerations, the problems of the economic viability of any surgical intervention in cattle must be carefully assessed. The importance of sterile surgical packs, effective anaesthesia and asepsis cannot be overemphasised. Failures in operative procedures in cattle lead to a natural reluctance by farmers to agree to repeat such operations. The attention today (2018) on the worldwide attempts to reduce antibiotic usage is also relevant to bovine surgery, where effective asepsis often makes post-operative antibiotic cover unnecessary.

The quality of veterinarian-farmer communication is particularly relevant at a time when ethical considerations have become more important. The general public is now more conscious of animal welfare and their view, as consumers and customers, should not be ignored. The veterinary profession has an important role here. For example, the need for pain relief should be promoted in routine procedures such as disbudding/dehorning and castration, frequently performed by the unsupervised farmer following instruction by the veterinarian. The relatively recent recognition of the usefulness of NSAIDs to reduce post-operative pain is applauded and their more widespread use is encouraged in this revised edition.

Other challenges in the bovine surgical field cannot be avoided, such as surgery in a suboptimal environment e.g. a dusty dark cowshed late at night, or the ill-lit corner of a field. More hypothetical challenges such as the layperson's question: “is castration justified?” fall outside our remit in this book. However, wherever possible a practical approach has been suggested, including some handy tips often learned the hard way.

Despite this book often describing the surgical correction of conditions once they occur, the reader is encouraged to make efforts to prevent problems, such as an unacceptable incidence of displaced abomasum cases, or of digital dermatitis. Whilst other books, (see further reading section) are able to explore preventive measures in greater depth, we have included in this edition some discussion boxes to promote a preventive approach.

The authors would welcome comments and suggestions for improvements. We have often given only our personal preferred surgical technique, aware that in other hands there can be excellent alternatives.

A. David Weaver, Owen Atkinson, Guy St. Jean and Adrian Steiner

March 2018

Acknowledgements

Permission to reproduce again illustrations from the first and second editions was graciously given by several authors and publishers as below.

Figs. 1.9, 4.5, 5.2, 5.12 Dr. K.M. Dyce, Edinburgh and W.B. Saunders ‘Essentials of Bovine Anatomy’, 1971 by Dyce and Wensing

Figs. 4.4, 4.9, 5.1, 5.4, 5.5 Professor Claude Pavaux, Toulouse, and Maloine s.a. editeur from ‘Colour Atlas of Bovine Anatomy: Splanchnology’ 1982

Fig. 5.17, Dr. John Cox, Liverpool, and Liverpool University Press ‘Surgery of the Reproductive Tract in Large Animals’ 1987

Fig. 3.3, Adapted from Dr. M.E. Smart, Saskatoon and Veterinary Learning Systems, Yardley, PA, USA from ‘Compendium of Continuing Education for the Practicing Veterinarian’ 7, S327, 1985

Fig. 5.20, Dr. H. Kümper, Giessen and Blackwell Science from ‘Innere Medizin und Chirurgie des Rindes’ 4e 2002 edited by G. Dirksen, H-D. Gründer and M. Stöber (fig. 6.125)

Fig. 6.6, Dr. R.S. Youngquist, Columbia, Missouri and W.B. Saunders from ‘Current Therapy in Large Animal Theriogenology’ 1997 (fig. 57.2)

Fig. 9.31, Dr. M. Steenhaut, Gent, and Blackwell Science from ‘Innere Medizin und Chirurgie des Rindes’ 4e 2002 edited by G. Dirksen, H-D. Gründer and M. Stöber (fig. 9.159)

The authors are grateful to the many practicing vets and colleagues who helped with previous editions, checking for inaccuracies, providing comment or drawing sketches. They include the American Association of Bovine Practitioners (AABP), Dominic Alexander, George Constantinescu, Keith Cutler, Jan Huckin, Lesley Johnson, David Noakes, David Pritchard, David Ramsay, Jonathan Reader, Phil Scott, John Sproat, Eva Steiner, David Taylor and Thomas Wittek. Thanks also to Dr. R.S. Youngquist and Colin D. Penny who reviewed the new Chapter 8.

David Weaver thanks Christina Mclachlan of Milngavie for both her accuracy and patience whilst typing large sections of manuscript.

Guy St. Jean thanks his mentors Bruce Hull, Michael Rings and Glen Hoffsis, not only for their earlier advice and encouragement during his residency, but also for their continuing friendship. He also thanks Kim Carey for secretarial help and his wife Kathleen Yvorchuk-St. Jean for continual support.

Adrian Steiner would like to dedicate the book to Christian.

Owen Atkinson thanks the farmers and many veterinary colleagues who have contributed to his understanding of bovine surgery and lameness. He thanks Laura for her support.

Finally thanks are given to all at Wiley Publishing for their expertise and encouragement through the writing of this third edition. They include Patricia Bateson, Catriona Cooper, Susan Engelken, Jessica Evans, Atiqah Abdul Manaf, Purvi Patel, and Justinia Wood.

A. David Weaver, Owen Atkinson, Guy St. Jean and Adrian Steiner

March 2018

The authors have made every effort to ensure that medicines and their dosage regimes are accurate at the time of publication. Nevertheless, readers should check the product information provided by the manufacturer of each medicine before its use or prescription. In particular, medicine authorisation by regulatory authorities varies from country to country. Some medicines included in the text are not authorised for use for food- producing animals in some countries. The reader should exercise individual judgement in coming to a clinical decision on medicine usage, bearing in mind professional skill and experience, and should at all times remain within the regulatory framework of the country.

Whilst all reasonable care has been taken in the book's preparation, including peer review, no warranty is given as to its accuracy, nor liability accepted for any loss or damage caused by reliance upon any statement in or omission from this publication.

About the Companion Website

This book is accompanied by a companion website:

www.wiley.com/go/weaver/bovine-surgery

The website includes:

Videos

Annotated PDF documents of videos

Chapter 1General Considerations and Anaesthesia

1.1 Pre-operative assessment

1.2 Instrumentation

1.3 Asepsis

1.4 Sutures and suturing

1.5 Restraint

1.6 Pre-medication and sedation

1.7 General anaesthesia

1.8 Local analgesics

1.9 Regional analgesia

1.1 Pre-operative Assessment

Introduction

The bovine patient is a stoical animal and modern crushes and physical restraint options allow many techniques to be carried out in the field. However, this should not excuse a thorough clinical and ethical assessment prior to any surgical procedure.

Assessment should include numerous factors apart from the physical condition of the subject:

welfare implications of the procedure

potential duration of a productive life

economic situation including insurance status and economic return on the surgery

surgical risk regarding complete recovery

future breeding prospects including heritability of the condition being corrected

pathology of other body systems directly or indirectly related to the primary condition

General physical examination is essential before emergency or elective surgery to assess risks and concurrent disorders.

Welfare and Quality of Life

Animal welfare may be judged using a number of criteria. Making these judgements is an essential part of the vet's role. Vets must also lead by example. Decisions to perform surgery, and how it is to be done, are complex. Foremost in the process must be the welfare of the cow or calf. The surgeon should ask themselves:

How necessary is this procedure: will benefits to the animal outweigh any pain or discomfort?

What will the animal's quality of life be afterwards? Is the procedure likely to lead to a ‘life worth living’ or preferably ‘a good life’ for the animal in question?

How does this procedure compare with an alternative option of humane slaughter or euthanasia?

To what extent can pain and discomfort be mitigated during and after the procedure?

To what extent can fear and distress be mitigated during and after the procedure?

What can we learn from this situation to make life better for cows and calves in the future?

The last question is vital: sometimes it is easy for the surgeon to focus on the individual animal in question (that is important too) but lose sight of the greater picture. For example: performing surgery on a cow with toe necrosis can greatly improve her quality of life, but what measures can be put in place to prevent further cases? You are asked to dehorn or castrate some yearling cattle: could it be done at a younger age next time?

Warning

Some procedures are deemed to be simply unethical and there is legislation in place preventing them, though there are regional variations. Examples in the UK of illegal procedures include:

tail docking in calves or adult cattle (except in cases of injury)

castration over one week by means of an elastrator

castration without anaesthetic for animals over two months of age

Furthermore, the Veterinary Surgeons Act means that any surgery involving entering a body cavity (e.g. joint spaces; abdomen; thoracic cavity) can only be carried out by a qualified veterinary surgeon in the UK. It is incumbent on the vet to provide suitable anaesthesia and analgesia.

Anaesthesia techniques are described in Section 1.7–1.9. Peri-operative analgesia is discussed in Section 2.11, though there is clearly overlap in these two areas of pharmacology and surgical preparation. The use of a crush/squeeze chute should never replace adequate analgesia and sedation for surgical procedures.

Tip

Learn and practice good communication techniques. Effective communication between farm vet and producer is vital to ensure that pain and suffering are reduced to a minimum among stock. Vets should be the leaders in animal welfare: this leadership requires exact personal skills, which is in addition to any technical abilities or scientific knowledge required of vets.

Laboratory Tests

Under farm practice conditions laboratory tests may not be performed, but major parameters very simply estimated with minimal apparatus are:

packed cell volume: microcentrifuge, microhaematocrit apparatus

total protein: refractometer

Normal haematological and biochemical parameters of cattle are listed in Table 1.1.

Table 1.1 Reference ranges (haematology and plasma biochemistry) in cattle.

Units

Average (%)

Range (± 2SD)

Haematology

Erythrocytes

×10

12

/l

7.0

(5–10)

Haemoglobin

g/dl

11.0

(8–15)

PCV (haematocrit)

1/l

35.0

28–38

Fibrinogen

g/l

4.0

(2–7)

Leucocytes

×10

9

/l

7.0

(4–12)

Neutrophils (non-segmented bands)

×10

9

/l

0.02 (0.5%)

0–1.12 (0–2%)

Neutrophils (segmented mature)

×10

9

/l

2.0 (28%)

0.6–4 (25–48%)

Lymphocytes

×10

9

/l

4.5 (58%)

2.5–7.5 (45–75%)

Monocytes

×10

9

/l

0.4 (4%)

0.02–0.8 (2–7%)

Eosinophils

×10

9

/l

0.65 (9%)

0–2.4 (0–20%)

Basophils

×10

9

/l

0.05 (0.5%)

0–0.2 (0–2%)

Neutrophil: lymphocyte ratio

—

0.45 : 1

—

Plasma biochemistry

Urea

mmol/l

4.2

2.0–6.6

Creatinine

μmol/l

100

44–165

Calcium

mmol/l

2.5

2.0–3.4

Inorganic phosphate

mmol/l

1.7

1.2–2.3

Sodium

mmol/l

139

132–150

Potassium

mmol/l

4.3

3.6–5.8

Chloride

mmol/l

102

90–110

Magnesium

mmol/l

1.02

0.7–1.2

Total protein

g/l

67

51–91

Albumin

g/l

34

21–36

Globulin

g/l

43

30–55

Glucose

mmol/l

2.5

2.0–3.2

Alkaline phosphatase

iu/l

24

20–30

AST SGOT

iu/l

40

20–100

ALT SGPT

iu/l

10

4–50

Lactate dehydrogenase (LDH)

iu/l

700

600–850

Bilirubin

μmol/l

4.1

0–6.5

Cholesterol

mmol/l

2.6

1.0–3.0

Creatine phosphokinase

mmol/l

3.0

0–50

The above values refer to healthy adult (> 3 years old) cattle, and have been compiled from various sources. Interpretation of possible deviations from the above ranges should consider variations due to the laboratory technique, breed, lactational and nutritional status, and should always be related to the presenting signs and symptoms of the individual or group. Units are given as SI units

In some abdominal conditions (abomasal torsion or volvulus, intestinal obstruction) estimation of plasma electrolytes (e.g. chloride) is valuable in assessing prognosis and calculating requirements for fluid replacement. Fluid therapy is discussed in Chapter 2.

Congenital Defects

Incidence of congenital defects in cattle is 0.2–3%, with 40–50% born dead. Most defects are visible externally. Congenital defects reduce the value of affected calves and economic losses are most severe when combined with embryonic or foetal mortality, particularly if it results in an extended subsequent calving interval. Close collaboration between the vet, farmer and geneticist is essential and good breeding records are vital.

Tip

‘Congenital’ is not synonymous with ‘heritable’ or ‘genetic’. Where it is likely that the condition is inherited, steps should be taken (e.g. castration, sterilisation) to avoid breeding from such stock. As it is not always easy to know if a congenital defect is heritable, a precautionary approach is best.

A limited number of conditions can be corrected surgically.

Examples of the more common defects of each body system are:

skeletal

: single and isolated defects include spinal abnormalities such as scoliosis, kyphosis, tibial hemimelia, polydactyly, syndactyly

systemic skeletal defects

: chondrodysplasia (dwarfism), osteopetrosis

joint defects

: arthrogryposis and congenital muscle contracture (‘ankylosis’), hip dysplasia, bilateral femorotibial osteoarthritis

muscular

: arthrogryposis, congenital flexed pastern and/or fetlocks, muscular hypertrophy, spastic paresis

CNS

: internal hydrocephalus, spina bifida, Arnold Chiari malformation (herniation of cerebellar tissue through

foramen magnum

into cranial cervical spinal canal), cerebellar hypoplasia, cerebellar ataxia, spastic paresis, spastic syndrome

skin

: epitheliogenesis imperfecta, entropion

cardiovascular

: ventricular septal defect, patent

ductus arteriosus

digestive

: atresia of ileum, colon, rectum and anus

hernias

: umbilical, scrotal/inguinal, schistosomus reflexus

reproductive

: testicular hypoplasia, intersex (hermaphrodite and freemartin), ovarian hypoplasia, rectovaginal constriction (Jerseys) and prolonged gestation

Many of the above musculoskeletal defects (e.g. muscular hypertrophy or double muscling in the Belgian Blue) can give rise to dystocia.

Surgical correction of several of these defects is considered elsewhere: umbilical hernia (see Section 5.13), rectal and anal atresia (see Section 5.15) and spastic paresis (see Section 9.27).

1.2 Instrumentation

A good worker needs good tools. Maintain instruments in good condition and store in sterile surgical packs for the common procedures (caesarean section, laparotomy and teat surgery).

Sterilisation

Instrument sterilisation methods include the following (the first two are recommended) (see Tables 1.2. and 1.3):

autoclaving

by pressurised steam, 750 mm/Hg at 121 °C for 15 minutes or at 131 °C for three minutes for non-packed instruments, or for a shorter time in high vacuum or high pressure autoclaves; 30 minutes for packs at 121 °C or 18 minutes at 134 °C.

gas sterilisation

by ethylene oxide followed by air drying for several days to avoid diffusion of residual gases from the materials into animal tissues. Some acrylic plastic materials, polystyrene and certain lensed instruments may be damaged during this process.

cold (chemical) sterilisation

in commercially available solutions (e.g. containing glutaraldehyde). Prolonged immersion is necessary. Most equipment that is safe for immersion in water is safe for immersion in 2% glutaraldehyde. After the proper immersion period, instruments should be rinsed with copious amounts of sterile water.

simple boiling

of instruments: a poor, slow and tiresome means of reduction of infectious agents likely to cause damage. The minimal period of boiling is 30 minutes, longer at altitudes over 300 m. Addition of alkali to the steriliser increases bactericidal efficiency and boiling time may be safely reduced to 15 minutes. Corrosion is avoided by the addition of 0.5–1% washing soda (Na

2

CO

3

). Accumulation of lime in serrations or joints is removed by leaving instruments in 5% acetic acid overnight and then brushing off.

Warning

Ethylene oxide and glutaraldehyde are carcinogenic: environmental and safety hazards associated with these chemicals are numerous and severe.

Table 1.2 Suitability of various surgical materials for sterilisation.

Dry heat

Autoclave

Boiling water

Ethylene oxide

Liquid chemicals

PVC (e.g. endotracheal tubes)

no

yes

yes

yes

doubtful

Polypropylene (e.g. connectors)

no

yes

yes

yes

yes

Polyethylene (e.g. catheters, packing film)

no

no

yes

*

, no

†

yes

yes

Nylon (e.g. i.v. cannulae)

no

yes

yes

no

doubtful

Acrylic (e.g. perspex)

no

no

doubtful

yes

yes

Silicon rubber

yes

yes

yes

yes

doubtful

*

high density,

†

low density

Table 1.3 Efficiency of different methods of sterilisation.

Bacteria

Dry spores

Moulds

Fungi

Viruses

Autoclaving

+

+

+

+

+

Gas sterilisation

+

+

+

+

+

Chemical antiseptics

+

—

+

(+)

+

Boiling

(+)

—

(+)

(+)

(+)

Abbreviations: + = effective; (+) = limited efficacy; — = not effective

Basic Instruments for Caesarean Section or Laparotomy

The following is a suggested list of equipment to cover most eventualities (see Figure 1.1):

towel clamps (Backhaus) × 4, 8.8 cm

haemostatic forceps (Spencer Wells) × 4 straight 15.2 cm, (Criles) × 2 curved 14 cm, (Halsted) × 2 mosquito straight 12.7 cm

scalpel handle (Swann-Morton® or Bard-Parker®) × 2, P (no. 4, blades no. 22, or handle no. 3 and blade no. 10)

rat tooth dissecting forceps (Lane) 15.2 cm

plain dissecting forceps (Bendover) 15.2 cm

straight scissors (Mayo) 16 cm

needle holder (McPhail's or Gillies), right- or left-handed 16 cm

Allis tissue forceps × 4, 15 cm

sterile nylon calving ropes for caesarean section × 4

embryotomy finger knife (for incision into the uterine wall, which cannot be brought near the body wall)

Figure 1.1 Basic instruments for caesarean section or laparotomy.1. Allis tissue forceps; 2. McPhail's needle holder; 3. Gillies combined scissors and needle holder; 4. plain forceps; 5. rat tooth forceps; 6. Mayo scissors (blunt/blunt), slightly curved; 7. Mayo scissors (pointed/blunt), straight; 8. straight haemostatic forceps; 9. curved haemostatic forceps; 10. scalpel handle no. 4 and no. 22 blade; 11. scalpel handle no. 3 and no. 10 blade; 12. towel clip (Backhaus).

Also needed are suture needles. Two each of the following types and sizes are recommended (see Figure 1.2):

3/8 circle cutting-edged 4.7 cm and 7.0 cm

3/8 circle round-bodied (taper cut) 4.5 cm

1/2 circle cutting-edged 4.6 cm

1/2 curved cutting-edged 6.7 cm

swaged-on curved round-bodied needle 4.5 cm

intestinal straight round-bodied (Mayo) 6.2 cm

straight cutting-edged (Hagedorn) 6.3 cm

double-curved post-mortem needle 12.5 cm

Figure 1.2 Suture needles (shown full scale).1 and 2. 3/8 circle cutting-edged 4.7 and 7 cm; 3. 3/8 circle round-bodied (taper cut) 4.5 cm; 4. 1/2 circle cutting-edged 4.6 cm; 5. 1/2 curved cutting-edged 6.7 cm; 6. intestinal straight round-bodied (Mayo) 6.3 cm; 7. straight cutting-edged (Hagedorn) 6.3 cm; 8. double-curved post-mortem needle 12.5 cm.

1.3 Asepsis

Surgery involving regions where adequate skin preparation is feasible (i.e. with avoidable microbial contamination of tissues or sterile materials) should be performed under aseptic conditions. Instruments and cloths should be sterile.

Preparation of Operative Field

This example is for the flank:

close clip wide area, minimum 60 cm cranial-caudal and 90 cm vertically (preferable to shaving)

alternatively shave operative field after application of disinfectant, soap and water (Schick razor is suitable)

wash area with soap and water twice, then scrub with povidone-iodine solution or 4% chlorhexidine gluconate, dry off, wash with 70% alcohol and rescrub

repeat this procedure three times before respraying with diluted povidone-iodine solution or chlorhexidine solution

large impervious sterile towels or disposable drapes (rubber or plastic) are useful for placing on the site

place sterile towel on suitable flat surface for instruments, use sterilised gauze swabs, instruments and suture materials, and sterile gloves

Tip

Using sterile isotonic saline instead of alcohol for rinsing after scrubbing with chlorhexidine is preferable as it does not reduce the long-term effect of chlorhexidine. Never mix povidone-iodine with chlorhexidine solution.

Hand Disinfection

For ‘scrubbing up’, effective hand and forearm sterilisation procedures include (see Table 1.4):

commercial chlorhexidine ‘scrubs’

0.5% chlorhexidine concentrate in 90% ethyl alcohol with 1% glycerine as emollient (cheapest)

commercially available povidone-iodine soaps

hexachlorophane suspension (requires a full rinse-off after a 5 minute scrub)

10 ml is first applied to clean dry hands and permitted to dry, before further application and a 5 minute scrub-up. At least five minutes contact time is required for all disinfectants

sterile surgical gloves should be worn whenever practicable after scrubbing up

Table 1.4 Properties of three common antiseptic compounds.

Generic name

Povidone-iodine

Chlorhexidine gluconate or acetate

Benzalkonium chloride

Bactericidal

+

+

(+)

Fungicidal

+

+

+

Virucidal

+

—

—

Dilution for instruments

undiluted (5%, 7.5% or 10%)

10% diluted 1:500

Skin (‘scrub’)

undiluted (0.75%)

4% or 15 ml of 7.5% solution + 485 ml of 70% alcohol

10% diluted 1:100

Wound lavage

0.1%

0.05%

—

Disadvantages

brown skin when dry

incompatible with soap and anionic detergents

incompatible with soap and anionic detergents; fails to kill spore-bearing organisms

Advantages

not inactivated by organic matter

not inactivated by organic matter

—

Abbreviations: + = active; (+) = limited activity; — = no activity

1.4 Sutures and Suturing

Suture materials are constantly being improved and new products come on to the veterinary market at regular intervals (see Table 1.5). This section selects a limited number of materials and methods of usage, and attempts to justify the selection. In few cases can the cost of the material be considered an important factor in selection.

Table 1.5 Comparative qualities (graded undesirable to desirable, + to +++), of nine selected suture materials for cattle.

Generic name (trade name examples)

Origin

Tensile strength

Knot security

Handling

Tissue reaction

Resistance to infection

Absorption without inflammation after tissue repair

Cost

Absorbable

Chromic catgut

collagen

(+)

+

++

+++

+

+

low

Coated braided PGA (PGS), (Dexon Plus®)

glycolic acid polymer, coated surfactant

++(+)

++

++(+)

++

++

++

high

Polydioxanone monofilament (PDS)

polymer of paradioxanone

+++

++

++

+

+++

+

high

Coated braided Polyglactin 910 (coated Vicryl®)

glycolic-lactic acid copolymer

++(+)

++

+

++

++

++

high

Monofilament polyglyconate (Maxon)

copolymer of glycolic acid and trimethylene

+++

++

+

+++

+

high

Non-absorbable

Polypropylene monofilament (Prolene, Surgelene®, Prodek®)

polymerised polyolefin hydrocarbons

+++

(+)

+(+)

(+)

+++

NA

low

Surgical steel

alloy of iron

+++

+++

+

+

+++

NA

low

Monofilament nylon (Dermalon®, Ethilon, Surgidek®)

polyamide filament

++(+)

+

+

+

+

NA

low

Polyfilament polyamide polymer (Suprylon®, Vetafil®, Braunamid®)

polyamide polymer

++(+)

++

+++

+

++

NA

low

NA = not applicable

Suture Materials

Non-absorbable suture materials:

monofilament nylon (e.g. Ethilon®): skin

monofilament polypropylene (e.g. Prolene®): skin

pseudomonofilament polyamide polymer (e.g. Supramid®): skin

mono- or multifilament surgical steel: skin, bone; exceptionally

linea alba

Absorbable suture materials:

chromic catgut: subcutis, muscle, peritoneum, bowel, urinary bladder, uterus, penis

multifilament polyglycolic acid or PGA (e.g. Dexon®): bowel, muscle including teat intermediate layer

multifilament polyglactin 910 (Vicryl®): subcutis, muscle including teat intermediate layer, bowel, urinary bladder

monofilament polyglyconate (e.g. Maxon®): subcutis, bowel, teat intermediate layer, urinary bladder, uterus

monofilament polydioxanone (PDS): bowel, muscle,

linea alba

‘soft’ gut (Softgut®): muscle, bowel, teat intermediate layer

Tip

Suture patterns are discussed under the specific procedures. Skin under considerable or potential tension at certain sites, such as the vulval lips and peri-anal region (e.g. following replacement of prolapsed cervix or rectum), is usually sutured with sterile woven nylon tape 3–5 mm in diameter.

Discussion

Selection of suture material should be based on the known biological and physical properties of the suture, wound environment and tissue response to the suture.

Monofilament nylon

remains encapsulated in body tissues when buried, but the inflammatory reaction is minimal. It has a great size-to-strength ratio and tensile strength. It is somewhat stiff and is therefore not particularly easily handled, an important point when operating in sub-optimal conditions of poor light and awkward corners. Knot security is only fair.

Multifilament polyamide polymer

, encased in an outer tubular sheath (pseudomonofilament), has good strength and provokes little tissue reaction unless the outer sheath is broken, but it loses strength when autoclaved. It is therefore usually drawn from a sterile spool as and when required. It is very easily handled.

Surgical steel

has the greatest tensile strength of all sutures and retains strength when implanted. It has the greatest knot security and creates little or no inflammatory reaction. Surgical steel, however, tends to cut tissue, has poor handling and cannot withstand repeated bending without breaking. It is sometimes used in tissues that heal slowly (e.g. infected

linea alba

or bone).

Chromic catgut

, of the six absorbable materials listed, is still most commonly used, but synthetic absorbable material does have distinct advantages. Catgut has relatively good handling characteristics, but has disadvantages of relatively rapid loss of strength in well vascularised sites (50% in the first week) and poor knot security (tendency to unwrap and loosen when wet). The potential minute risk of the transfer of infectious prion material into food-producing animals and hence into the human food chain has led to a ban on the use of chromic catgut in some countries (vCJD risk)

Multifilament polyglycolic acid

(PGA) has greater strength that is lost evenly, provoking much less tissue reaction than chromic catgut. PGA is non-antigenic, has a low coefficient of friction and therefore requires multiple throws to improve knot security, but is easily handled.

Monofilament polydioxanone

(PDS) is very strong, retaining its strength for many weeks (58% at four weeks), is characterised by its strong memory and has low knot security, but provokes minimal tissue reaction.

Linea alba

is best sutured with PDS.

‘Soft’ catgut

is undoubtedly the most easily handled absorbable material for delicate bowel anastomoses. Plain or soft catgut is absorbed quickly and maintains its strength for a short time.

PDS and PGA are slowly replacing chromic catgut, which will retain its place as a general purpose material. Vicryl® in its coated form is very easy to handle and has minimal tissue reaction and tissue drag. It is stable in contaminated wounds. Polyglyconate monofilament (Maxon™) has three times the strength of Vicryl® at day 21 of wound healing.

1.5 Restraint

Introduction

Restraint is necessary for:

administration of drugs for (a) pre-medication and sedation, (b) infiltration of local analgesic drugs and (c) induction of general anaesthesia

examination and minor procedures carried out without sedation or analgesia/anaesthesia

prevention of movement during surgery

safety of operators

Restraint may involve physical manipulation of tail, head or nostrils, or involve application of halter and ropes.

Techniques

Physical restraint by a stock person includes:

halter

nose grip (fingers or nose tongs)

tail elevation

skin grip of crural fold

calves in lateral recumbency: lifting bottom fore leg and hind leg with elbow pressure on neck

Rope restraint includes:

hind limb elevation by a rope above the hock and round an overhead bar

Reuff's method of casting (see

Figure 1.3

), employing a rope squeeze of the abdomen

Figure 1.3 Reuffs method of casting a cow with a rope and maintaining in lateral recumbency.The first operator (1) brings the cow's head round tightly to her right shoulder, using a halter. The second operator (2) pulls the rope so that it tightens around the cow's abdomen: this will force her to lie down. In this example the cow will go into lateral recumbency on her left side. Maintaining tension on the rope (2) will prevent her rising.

Many forms of cattle crush or squeeze chute are available with an excellent head restraint, which are suitable for surgery of the head and cranial neck (e.g. tracheotomy) and of the perineum. Many are unsuitable for flank laparotomy, caesarean sections or rumenotomy, though an increasing number of manufacturers offer modified crushes to improve access to the paralumbar fossa. A veterinary practice may find it advantageous to have such a crush available for surgery on the practice premises or to be transported to the farm. Some crushes have poor facilities for the elevation and restraint of hind or fore limbs for clinical examination and digital surgery. The Wopa crush is an example of an excellent crush for digital surgery.

Warning

An essential feature of crushes or chutes is the need to release the head rapidly should the animal collapse. Asphyxiation can result, or pressure on the point of the shoulder can cause irreversible radial nerve paralysis and a ‘downer cow’.

1.6 Pre-medication and Sedation

Pre-medication and sedation (see Table 1.6) have six aims:

to improve handling and restraint; improve safety

to enhance the analgesic effect produced by other anaesthetic agents

to reduce the induction and maintenance doses of general anaesthesia (GA) agents

to reduce the possible disadvantageous side-effects of anaesthesia

to promote smooth post-operative recovery

to improve the well-being of the animal

Table 1.6 Activity and dosage of selected analgesic, anti-inflammatory and sedative drugs in cattle.

Drug (example trade name)

Analgesic

NSAID

Sedative

Dosage (mg/kg)

i.m.

i.v.

Butylscopolamine bromide/metamizole (Buscopan® Boehringer)

+

+

–

5 ml/100 kg

a

Meloxicam (e.g. Metacam® Boehringer)

+

+

–

0.5

b

0.5

Carprofen (Rimadyl® LA soln, Zoetis)

+

+

–

1.4

b

1.4

Xylazine (e.g. Sedaxylan® 2%, Dechra)

+

–

+

0.05–0.3

0.03–0.1

Diazepam (Valium®)

*

+

–

+

0.5–1.0

0.2–0.5

Flunixin meglumine (e.g. Finadyne®, MSD)

+

+

–

–

2.2

Ketoprofen (e.g. Ketofen® 10%, Merial)

+

+

–

3

3

Acetylpromazine

*

(ACP®)

–

–

+

0.03–0.1

0.03–0.1

*

Not authorised for use in cattle in UK and EU, may only be given ‘off label’ under cascade prescribing

a

not authorised in lactating cattle

b

by s.c. route, not i.v.

Very few anaesthetic drugs are approved for use in farm animals. Those known to the authors include azaperone, procaine, lignocaine (lidocaine), methoxyflurane and thiamylal (USA). Xylazine is approved for use in cattle in Canada, the UK and Switzerland, and acepromazine (ACP) is also approved for use in cattle in Canada. Lignocaine is not licensed in EU countries for food-producing animals.

Although possibly not approved for use in cattle in many countries (including the USA), several non-steroidal anti-inflammatory (NSAID) analgesics (e.g. flunixin meglumine, dipyrone 50% (metamizole), ketoprofen and meloxicam) are beneficial as adjunct therapy both pre- and post-operatively in cattle with obvious somatic pain and discomfort. Pre-operative use of analgesics reduces the degree of operative discomfort and post-operative pain.

Warning

For any medication for cattle in the USA, it is the veterinarian's responsibility to consult the Animal Medical Drug Use Clarification Act for guidelines for the extra-label use of drugs and the Food Animal Residue Avoidance Databank (FARAD) for withdrawal times. Under EU legislation, the prescribing cascade can be used to prescribe ‘off licence’ under certain conditions and following guidelines, but additional withdrawal periods are required. UK practitioners should consult Veterinary Medicines Directorate (VMD) guidelines for cascade regulations. Only medicines that have pharmacologically active substances listed in a Table of Allowed Substances (European Medicines Agency) may be used in animals intended for food production, regardless of the cascade.

Xylazine (e.g. Rompun 2%® [Bayer]; Sedaxylan [Dechra Veterinary Products])

Advantages

Very useful analgesic and sedative. Licensed for use in cattle (EU). Xylazine also causes muscle relaxation.

Disadvantages

Causes ruminal stasis, increases salivation, uterine tone and effects of higher dose rate are somewhat unpredictable as animal may or may not become recumbent.

Xylazine is unsuitable as the sole agent for minor surgery when more than a single painful stimulus is anticipated (e.g. unsuitable as the method of analgesia in teat surgery; lancing and drainage of large flank abscess is a suitable indication).

Xylazine is contra-indicated in the last trimester of pregnancy due to its stimulation of uterine smooth muscle (risk of abortion). It may be used if a uterine relaxant is given before xylazine.

Xylazine is contra-indicated in extreme heat, as hyperthermia may result.

Avoid accidental intra-carotid injection! Violent seizures and possibly temporary collapse are likely.

Unsuitable for placing in dorsal recumbency (e.g. certain DA surgery techniques) due to the risk of ruminal regurgitation and subsequent aspiration pneumonia.

Dosage and Antagonists

For anaesthetic pre-medication: 0.1 mg/kg xylazine i.m.

For minor procedures in combination with local analgesia: 0.2 mg/kg i.m.

A faster and more predictable effect is seen following i.v. 0.1 mg/kg (not authorised for all preparations).

Xylazine sedation, analgesia, cardiopulmonary depression and muscle relaxation are reversible. Also xylazine overdosage (e.g. by inadvertent use of the equine preparation) may be antagonised by different drugs including:

– yohimbine alone (0.2 mg/kg i.v.)

– tolazoline (4 mg/kg i.v.) – fast onset

– atipamazole (Antisedan® [Zoetis]) 0.02–0.05 mg/kg i.v.

– atropine (100 mg s.c.) to counteract bradycardia and hypotension

– doxapram HCl or doxapram 4-aminopyridine respectively 1 mg/kg and 0.3 mg/kg i.v. significantly reduces recovery period

– mixture of doxapram (1 mg/kg i.v.) and yohimbine (0.125 mg/kg i.v.)

Tip

Doxapram acts by direct action on aortic and carotid chemoreceptors and medullary respiratory centre, while yohimbine antagonises xylazine sedation by blocking central alpha 2-adrenergic receptors. Therefore an alpha 2 antagonist such as yohimbine, tolazoline or atipamazole would be preferable to reverse accidental overdosage, though there are no licensed preparations for cattle.

Atipamazole (Antisedan®) can be given 0.025 mg/kg i.v. and 0.025 mg/kg i.m. to avoid resedation. This roughly equates to using a similar volume of 2% xylazine used but splitting it 50:50 between i.v. and i.m. routes. Overdosage can cause hyperactivity and excitement.

Chloral Hydrate

Advantages

cheap

given orally or i.v.

dose-dependent narcosis

patient generally maintains a swallow reflex at usual dose rates so less risk of regurgitation/aspiration pneumonia, particularly for placing the cow in dorsal recumbency (e.g. LDA surgery or teat repair)

Disadvantages

very irritant: can cause severe necrosis if accidental perivascular injection

narcosis deepens after i.v. infusion: risk of over-dosage

hepatotoxic: avoid in neonates

not licensed

not analgesic: local anaesthesia required in addition when used prior to surgery

Dosage

Orally: 50–100 mg/kg as 5% solution produces recumbency and light hypnosis in adult cow in 10–20 minutes. Equivalent to 35–70 g for adult Holstein cow.

Adult bulls require much higher oral dose: 120–160 g. Oral solutions are unpalatable even at high dilution so drenching or stomach tube is required.

I.V. infusion: 80–90 mg/kg in 10% solution has faster effect (2–3 minutes). Give slowly i.v. (over 5 minutes) as hepatic metabolism to the active trichloroethanal causes a delay in effect.

50–60 g made up with water in a 500 ml bottle and administered slowly i.v. via a flutter valve gives suitable sedation for recumbency and positioning in dorsal recumbency for most adult Holstein cows.

Warning

Chloral hydrate is very irritant perivascularly. It is safer to administer i.v. using a catheter. If extravascular injection occurs, the area should be infiltrated with up to 1 litre saline. Anaesthesia should then not be attempted for at least 24 hours unless the procedure is vital and life saving.

Acetylpromazine (ACP)

i.m. or slow i.v. injection

variable effect in cattle but may reduce stress response;

no analgesic effect

causes hypotension: avoid in depressed or hypovolaemic patients

avoid prior to GA: increased risk of regurgitation

causes penile prolapse in bulls (variable): may be advantageous for penile examination but risk of paraphimosis if left unattended

Diazepam

produces sedation i.v.; expensive

more predictable effect/useful in calves (economically more viable), particularly prior to GA

good muscle relaxation but no analgesia

Pentobarbitone

mainly used as sedative/anticonvulsant in cases of hypomagnesaemia

1.5–2 mg/kg i.v. can provide effective standing sedation in adult cattle for 60–90 minutes

avoid in calves: hepatic recycling and re-sedation likely

do not use preparations intended for euthanasia:

the preservatives can cause massive haemolysis

Atropine Sulphate

reduces quantity and increases viscosity of saliva

pre-medicant dose in adult cow is 60 mg s.c.

1.7 General Anaesthesia

Indications

General anaesthesia (GA) is rarely indicated in cattle. It is practised if the usual techniques of regional and local analgesia either cannot be adopted or fail. Specific indications include extensive surgery of the head, neck, chest and abdomen, or body wall, as well as most long bone fractures when maximum relaxation is desired. GA has a relative surgical indication when complete asepsis is essential, such as in umbilical hernia repair in calves. For GA, food should be withheld for 6–12 hours in calves and for up to 36 hours in adult cattle. Restriction of water is not indicated in calves and should not exceed 12 hours in adults.

Disadvantages of GA

Risks of GA in cattle include regurgitation, ruminal tympany, poor oxygenation and skeletal injury.

Risk of regurgitation

and subsequent aspiration of ruminal contents and saliva into the trachea, bronchi and alveoli with potential lethal consequences (necrotic laryngotracheitis and necrotising broncho-pneumonia with pulmonary oedema). Endotracheal intubation is therefore

essential

to avoid this problem.

Factors affecting regurgitation include:

depth of anaesthesia (see

Table 1.7

): light level provokes active regurgitation, deep level passive regurgitation

degree of ruminal distension or tympany

fluidity of ruminal contents

body and head/neck position

body movement: struggling and repositioning of animal

volume of saliva

duration of anaesthesia

Risk of severe ruminal tympany

. During recumbency the cardia is submerged in ruminal fluid, preventing normal eructation. Meanwhile, fermentation continues and gas builds up. Less of a problem in calves, depending on the stage of rumen development.

Risk of severe compromise

of the effective expansion capacity of lungs as a result of:

increased abdominal size following development of ruminal tympany causing pressure on diaphragm;

relatively poor oxygenation of the dependent lower lung due to inadequate circulation and pressure (ventilation–perfusion mismatch). Poorly oxygenated blood from ventral lung mixes with better oxygenated blood from upper dorsal lung, giving lowered systemic oxygenation and hypercapnia.

Risk of skeletal injury

in induction and recovery, involving possible dislocation, myositis and nerve paralysis.

Expense and size of gaseous anaesthetic equipment and appropriate expertise in its use.

Table 1.7 Main signs for assessing anaesthetic depth.

Surgical anaesthesia

Excessive depth

*

Cardiovascular system

Heart rate and rhythm

within normal limit

bradycardia, impending arrest

Mucous membrane colour

pink

cyanotic

Capillary refill time

< 2 s

> 3 s

Respiratory system

Respiratory rate

near normal

shallow, irregular, gasping, apnoea

Tidal volume

reduced

more reduced

Character

regular

irregular

Ocular signs

Position and size of pupil

moderately constricted, possibly rotated down

very dilated, centrally fixed

Palpebral reflex

present

very slow or absent

Corneal reflex

present

slow

Musculoskeletal system

Muscle tone

(lower jaw, limbs)

moderate

poor or absent

Other signs

Swallowing reflex

absent

absent

Salivary flow

present, profuse

absent

Lacrimal secretion

present

absent

*

Actions to take in case of excessive depth:

note time

check patency of airway

stop any volatile anaesthetic administration, give oxygen and artificial respiration

check heart rate (for five seconds)

check respiratory rate and character (for five seconds)

check other vital signs (see above)

Equipment

Apparatus for GA of cattle older than three to six months is similar to that available for horses. Endotracheal intubation is essential in bovine GA. Equipment for volatile and gaseous agents is of a circle and to-and-fro pattern, incorporating a soda-lime canister and re-breathing bag with calibrated vaporiser (0–5%) to volatilise isoflurane or halothane by means of oxygen delivered by a pre-set flowmeter. The minimum internal diameter of airways in such an apparatus should be 4 cm.

Equipment for GA of calves with gaseous agents is similar to that for larger breeds of dog. The airway diameter, although theoretically inadequate, is unlikely to produce disadvantageous side-effects. Endotracheal tubes for calves should have an internal diameter of 12–16 mm, while those for adult cattle should be about 24–30 mm. Tubes of siliconised PVC are approximately one quarter the price of rubber endotracheal tubes (adult cattle).

List of equipment for GA by gaseous or volatile agents:

anaesthetic apparatus: circle or to-and-fro system

endotracheal tubes (calf–adult: 12–25 mm)

syringe for inflation and clamping-off of cuff

mouth gag (e.g. Drinkwater model)

laryngoscope (e.g. Rowson pattern): optional for adults

nasogastric tube to act as a guide, over which the endotracheal tube is passed (alternative)

halothane or isoflurane and oxygen supply

ruminal trocar and cannula

Placing the endotracheal tube in adults is best done manually using a gag to hold open the mouth. For calves, a laryngoscope with a long blade is usually necessary.

Warning

Do not use local anaesthetic lubricants on endotracheal tubes in cattle: this will anaesthetise the larynx and abate the protective laryngeal and cough reflexes. A greater risk of inhalation of regurgitated material/saliva will occur during the recovery period.

Intravenous Anaesthesia (Induction) Agents

Intravenous agents for GA of cattle include:

thiopentone sodium

(no longer available in North America). Give as 10% solution by rapid i.v. injection, dose 1 g/100 kg 10 minutes after xylazine pre-medication or 1.2 g/100 kg if unpre-medicated. Perivascular injection is irritant: infiltration of 500 ml saline with hyaluronidase is essential to prevent perivascular necrosis and skin slough. 2.5% (larger volume) is safer. Catheter is advisable. Induction within 45 seconds with usually a brief period of apnoea. Duration of GA 5–8 minutes. Recover to stand in 30–60 minutes. Unsuitable for young calves < 3 months (prolonged recovery). Unsuitable for incremental doses to prolong anaesthesia

ketamine and xylazine

. Xylazine is given i.v. (0.1 mg/kg) or i.m. (0.2 mg/kg), followed immediately by i.m. ketamine (2 mg/kg). GA lasts for 10–20 minutes. Recovery is fairly rapid (on feet within 25–45 minutes). The two drugs may be mixed in one syringe and given i.m. (for calves: GA approximately 30 minutes and recovery in a further 90 minutes). Incremental doses (quarter or half doses of each agent) may be used successfully, but do not use ketamine on its own

ketamine, xylazine and guaiphenesin

. A mixture of 500 mg of ketamine and 50 mg of xylazine is added to a 500 ml bag or bottle of a 5% guaiphenesin solution. This combination is infused at 0.55 ml/kg to induce anaesthesia followed by 2.2 ml/kg/hour (adults) or 1.65 ml/kg/hour (calves) for maintenance. This combination produces good muscle relaxation and smooth recovery

After any intravenous GA technique endotracheal intubation should be carried out as soon as possible after injection. The tube should only be removed following a demonstrable cough reflex or swallowing movement. Extubation is performed with the head lower than the trunk and with the cuff inflated until it reaches the pharynx, preventing material moving between the tube and tracheal mucosa, dribbling towards the bifurcation of the bronchi and causing a necrotic bronchotracheitis.

Immobilon™/Revivon™ is a large animal product that is a reversible neuroleptanalgesia (narcosis) with analgesia for restraint and surgical procedures with LA Immobilon, the active principle of which is etorphine, combined with acetylpromazine. It is not licensed for use in cattle, but is sometimes used in exceptional circumstances where other methods of restraint are considered too hazardous. The drug is extensively used in various species in tropical Africa, but rarely now in the UK except for restraint of dangerous animals, e.g. a bull or steer amok in public places.

Warning

Immobilon is highly toxic, causing dizziness, nausea, pinpoint pupils, rapidly followed by respiratory depression, hypotension, cyanosis, loss of consciousness and cardiac arrest.

Etorphine can be life-threatening to the operator if absorbed by any route, including through skin or mucous membranes. Extreme care should be taken. Before any use of Immobilon the appropriate dose of the antagonist Revivon (contained in the same pack) should be drawn up first into a second syringe connected to a second sterile needle, which should then be kept close at hand for immediate intravenous use in the event of an accident. A second competent person should always be instructed clearly beforehand what action should be taken with the reversing agent, which should then be injected before calling medical assistance.

Indications and Dosage

Use with a dart gun (i.e. intramuscular injection) for restraint of dangerous and uncontrollable cattle.

0.5–1 ml Immobilon per 50 kg bodyweight i.m. by dart syringe. Cattle become recumbent some minutes later and remain immobile for about 45 minutes. Generalised muscle tremors and poor muscle relaxation are usually apparent.

To reverse the drug an equal volume of Revivon (diprenorphine HC1) should be injected i.v. Recovery generally occurs with minimal disturbance and noise. A second half dose of Revivon may be given s.c. after the initial i.v. dose if required.

The reader should consult specialised textbooks for further details of bovine GA.

1.8 Local Analgesics

The four local analgesics of greatest value today are the hydrochloride salts of lignocaine, procaine, bupivacaine and cinchocaine (see Table 1.8). In the EU, only procaine is licensed for use in cattle.

Table 1.8 Properties of four local analgesic drugs (all hydrochloride salts).

Generic name (example trade name)

Lignocaine (Lidocaine®)

Procaine (Ethocaine®)

Bupivacaine (Marcain®)

Cinchocaine (Dibucaine®)

Main indications:

surface analgesia %

2–10

NS

NS

0.25

infiltration %

0.5–1

2–3

0.25

0.25–0.5

Nerve block %

2–3

3–5

0.5

0.5

Epidural block %

2–3

3–5

0.5–0.75

0.5

Rate of diffusion

fast

slow

fast

slow

Duration of action

60–90 mins

<60 min

≃8 hours

≃8 hours

Analgesic potency

+

+

+

+++

Toxicity

+

+

+

++

Tissue irritation

low

low

low

low

Stability at boiling point

?

good

?

?

Cost (low → high: + → +++)

++

+

+++

++

Other properties

good safety margin, non- vasodilator

vasodilator, used with adrenalin

—

decomposes if mixed with alkalis

NS = not suitable

Lignocaine

In North America, lignocaine has largely replaced procaine as it has the advantages of:

extreme stability

more rapid diffusion (rapid onset)

longer duration of action

useful surface analgesic activity on mucous membranes and cornea

It is, however, no longer authorised for cattle in the UK and EU states, as it has no MRL. See the discussion box.

Preparations:

injectable solutions are usually 2–3%, though 1% is adequate for most uses

often contain adrenaline at 0.002% to prolong the activity and reduce the possibility of toxic side-effects

1% or 2% gel with chlorhexidine gluconate solution 0.25%, or hydrobenzoates in a sterile lubricant water-miscible base

aerosol spray (lignocaine 10%) with cetylpyridinium chloride 0.1%

5% cream

Discussion