Farm Animal Anesthesia

HuiChu Lin , DVM, MS, DACVAA, is a Professor of Anesthesia at the College of Veterinary Medicine at Auburn University in Auburn, Alabama, USA.

Paul Walz , DVM, MS, PhD, DACVIM, is an Associate Professor of Food Animal Medicine at the College of Veterinary Medicine at Auburn University in Auburn, Alabama, USA.

Contributing authors xii

Preface xiii

1 Preanesthetic considerations 1
HuiChu Lin

Positioning 2

Ruminal tympany 3

Regurgitation 3

Salivation 4

Malignant hyperthermia 6

Differences in sensitivity to anesthetics 6

Preanesthetic preparation 8

References 13

2 Commonly used preanesthetics 17
HuiChu Lin

Acepromazine (phenothiazine derivatives) 18

Cattle 18

Small ruminants and camelids 19

Swine 19

Droperidol and azaperone (butyrophenone derivatives) 19

Detomidine, medetomidine, romifidine, and xylazine (α2 agonists) 20

Cattle 21

Small ruminants and camelids 24

Swine 27

Atipamezole, tolazoline, and yohimbine (α2 antagonists) 28

Diazepam and midazolam

(benzodiazepine derivatives) 29

Cattle, small ruminants, and camelids 30

Swine 30

Chloral hydrate 31

References 31

3 Standing sedation and chemical restraint 39
HuiChu Lin

Cattle 39

Small ruminants and camelids 42

Swine 48

References 57

4 Injectable anesthetics and field anesthesia 60
HuiChu Lin

Injectable anesthetics 61

Ketamine 61

Telazol 64

Propofol 66

Guaifenesin 68

Field anesthesia 68

Cattle 68

Small ruminants and camelids 72

Swine 80

References 87

5 Inhalation anesthesia 95
HuiChu Lin

Cattle 101

Small ruminants and camelids 103

Swine 104

References 106

6 Perioperative monitoring and management of complications 111
HuiChu Lin

Perioperative monitoring 111

Supportive fluid therapy 116

Positioning 121

Recovery 123

Perioperative complications 123

Regurgitation and aspiration pneumonia 123

Airway obstruction 124

Ruminal tympany/bloat 125

Salivation 126

Hypoventilation 126

Cardiac arrhythmias 127

Hypotension 128

Hypothermia 129

Malignant hyperthermia 130

Postanesthetic neuromyopathy 131

Cardiovascular collapse 131

References 132

7 Local and regional anesthetic techniques 136
Misty A. Edmondson

Local anesthetics 136

Anesthesia for dehorning 137

Nasal anesthesia 137

Anesthesia of the eye 139

Eyelid 139

Eye and orbit 139

Anesthesia for laparotomy 141

Proximal paravertebral nerve block 141

Distal paravertebral nerve block 142

Inverted-L block 142

Line block 143

Anesthesia for reproductive procedures 144

Caudal epidural anesthesia 144

Continuous caudal epidural anesthesia 146

Lumbosacral epidural anesthesia 147

Sacral paravertebral nerve block 148

Internal pudendal nerve block 149

Dorsal penile nerve block 150

Castration 151

Teat anesthesia 152

Inverted-V block 152

Ring block 152

Infusion of teat cistern 152

Anesthesia of the distal limb 153

References 154

8 Anesthetic management for specific procedures 155
Benjamin Newcomer and Paul Walz

Umbilical hernias 156

Wounds, lumps, bumps, and abscesses 157

Wound management 157

Ocular squamous cell carcinoma 158

Enucleation 158

Entropion 159

Abscess removal 159

Surgical disorders of the abdomen 159

Laparotomy 159

Disorders of the forestomachs 161

Displacements and volvulus of the abomasum 162

Small intestine disorders (intussusception, intestinal volvulus, intestinal obstruction) 162

Urolithiasis and ruptured urinary bladder 163

Urogenital surgery in the female 164

Cesarean section 164

Ovariectomy 165

Vaginal prolapse 166

Perineal laceration 166

Urogenital surgery in the male 166

Castration 166

Penile translocation 168

Persistent frenulum 169

Penile papilloma 169

Epididymectomy 169

Vasectomy 169

Musculoskeletal indications 170

Dehorning 170

Claw amputation 171

Excision of interdigital fibromas 171

Tail docking 171

Rectal prolapse 172

References 172

9 Pain management for farm animals 174
HuiChu Lin

Local anesthetics 177

Systemic pain management 178

Opioid analgesics 178

Nonsteroidal anti-inflammatory drugs 183

Alpha-2 agonists 187

Ketamine 188

Gabapentin 188

Drug combinations for pain management 189

Constant rate infusion 190

Local or regional analgesia 197

Caudal epidural analgesia 197

Lumbosacral epidural anesthesia 198

Intra-articular analgesia 200

References 204

10 Fluid therapy 215
Paul Walz

General considerations 215

Physiology of body fluids 216

Patient assessment 218

Fluid and electrolyte therapy in the perioperative period 219

Quantity and rate of fluid administration 220

Fluid type 221

Method of administration 224

Monitoring fluid administration 226

References 227

11 Regulatory and legal considerations of anesthetics and analgesics used in food-producing animals 228
Thomas Passler

Alpha-2 agonists 231

Barbiturates 233

Benzodiazepines 233

Dissociative anesthetics 234

Local anesthetics 235

Opioids 236

Nonsteroidal anti-inflammatory drugs 238

Phenothiazine derivatives 241

Propofol 241

References 243

12 Euthanasia of farm animals 248
Thomas Passler

Considerations prior to euthanasia 248

The process of euthanasia 251

Methods of euthanasia 251

Injectable euthanasia drugs 252

Physical methods 253

Adjunctive and other methods of euthanasia 257

Considerations subsequent to euthanasia 258

References 259

Index 263