Large Animal Parasitology Procedures for Veterinary Technicians

Preface xv 1 Introduction to Large Animal Parasitology Procedures for Veterinary Technicians 1 Gastrointestinal Parasitism Can be Categorized into Four Distinct Periods of Development 22 Early Larvae Development and Translation Period 22 The Ingestion and Infective Prepatent Period 30 The Inhibition or Arrested Development Phase 31 The Patent Period 35 References 57 2 The Modified Wisconsin Sugar Flotation Method 59 Standard Operating Procedure for the “Modified Wisconsin Sugar Flotation Technique” 82 Interpretation of Fecal Worm Egg Counts in Sheep, Goats, and Camelids Using the Modified Wisconsin Sugar Flotation Technique 88 Quick Assessment for Sheep, Goats, and Camelids Based on Fecal Worm Egg Counts 97 References 106 3 Parasites in Beef Cattle 107 Strategic Deworming Entails More than Simply Applying a Dewormer 115 The Economics of an Aggressive Deworming Program 115 Interpretation of Fecal Worm Egg Counts in Cattle Using “The Modified Wisconsin Sugar Flotation Technique” 133 Fecal Egg Count Reduction Test (FECRT) 137 Product Profile of Fenbendazole (Safe-Guard®/Panacur® – Merck Animal Health) 137 Treatment Timing 142 Gastrointestinal and Lungworm Parasites Found in Beef Cattle 142 Stomach (Abomasal) Worms 142 Intestinal Nematode Parasites 142 Intestinal Cestode Parasites (Cattle Tapeworms) 158 Cattle Lungworm (Dictyocaulus viviparous) 158 Trematodes Parasites (Liver Flukes) 161 Protozoan Parasites of Cattle 162 References 167 4 Parasites in Dairy Cattle 171 Detection is Foremost in the Economic Analysis 171 Gastrointestinal and Lung Parasite Infections Found in Dairy Cattle (See Figure 4.8) 175 Stomach Worms 175 Intestinal Nematode Parasites 177 Intestinal Cestode Parasites (Cattle Tapeworms) 183 Cattle Lungworm (Dictyocaulus Viviparous) 185 Trematodes Parasites (Liver Flukes) 185 Protozoan Parasites of Cattle 185 Risk Factors and Production Losses Caused by Gastrointestinal Parasitism 188 How Many Parasites are Needed to Cause Clinical Disease? 188 Level of Efficiency Can Affect Production Losses 189 Variation in Parasites Numbers and Levels of Contamination Rates Exists 190 Age and Management Variations Affect Parasite Buildup in Animals 191 Understanding How Gastrointestinal Parasites Affect Lactating Dairy Cows 191 Monitoring Dairy Herds for Gastrointestinal Parasite Infections 192 Every Herd is Different when it Comes to Internal Parasitic Infections 192 The Following are Guidelines to Determine Parasite Exposure of a Dairy Herd Based on Animal Management 192 Obtaining a Comprehensive “Parasite Fecal Check” of the Herd Can be Important 193 Production Losses Due to Gastrointestinal Parasites 193 Seasonal Control of Gastrointestinal Parasitic Infections in Dairy Operations 193 Conclusion 197 References 198 5 Parasites in Equine 199 Gastrointestinal Nematode Parasites Affect Horses in Many Ways 200 Parasites Develop Differently in Horses than in Cattle 202 Parasite Resistance to Dewormers has Become a Major Problem 206 The Seasonal Transmission of Parasites in the Horse 208 Seasonal Control of Parasites in Horses Can be Achieved by Reducing Parasite Contamination from the Environment 211 General Recommendations for Strategic Timed Deworming for the Season Control of Gastrointestinal Parasites in Horses 212 A Two-Year Study Demonstrating the Value of Strategic Deworming to Reduce Environment Contamination was Conducted in Nevada 213 Equine Dewormers 217 Fecal Monitoring is the Best Way to Determine Whether Treatment is Effective 218 The Major Gastrointestinal Nematode Parasites of Horses are 219 Other Notable Internal Parasites of the Horse 219 Review of Internal Nematode Parasite of Horses 219 Other Parasites 228 Guide for Interpretation of Fecal Worm Egg Counts in Horses Using “The Modified Wisconsin Sugar Flotation Technique” 231 Quick Assessment for Equine Based on Fecal Worm Egg Counts 231 Inhibited Small Strongyles Cause Problems with Worm Egg Count Interpretations 231 References 232 6 Parasites of Swine 235 Large Roundworms (Ascaris suum) 241 Background 241 Diagnosis in Lungs 243 Diagnosis in Liver 245 Diagnosis in the Feces 245 Whipworms (Trichuris suis) 247 Background 247 Diagnosis in the Cecum 247 Diagnosis in the Feces 250 Threadworms (Strongyloides ramsoni) 252 Background 252 Diagnosis in the Feces 252 Treatment Guidelines 253 Nodular Worms (Oesophagostomum dentatum) 253 Background 253 Diagnosis in the Large Intestine 254 Diagnosis in the Feces 255 Treatment Guidelines 257 The Development and Buildup of Parasitism within a Swine Operation Depends on Many Factors 257 Materials and Methods for Fecal Sampling 258 Specific Sample Instructions 258 Fecal Worm Egg Count Interpretation and Whole Herd Deworming Guidelines 259 Treatment to Control Parasitism and Reduce Parasite Future Contamination in a Facility 260 Developing Parasite Data for Swine Clients 261 References 261 7 Parasites in Small Ruminants 263 Strategic Deworming for Small Ruminants 278 Phase I: “0–3–6–9” Spring Dewormings 278 Phase II – Fall Cleanup Deworming 280 Summary 280 Fecal Monitoring is the Best Way to Determine Whether Treatment is Effective 280 Interpretation of Fecal Worm Egg Counts in Small Ruminants Using the Modified Wisconsin Sugar Flotation Technique 284 Quick Assessment for Sheep, Goats, and Camelids Based on Fecal Worm Egg Counts 284 Gastrointestinal and Lung Parasite Infections Found in Small Ruminants 285 Stomach Worms 286 Intestinal Nematode Parasites 288 Intestinal Cestode (Tapeworm) Parasites (Moniezia expansa and Moniezia benedeni) 300 Trematodes Parasites (Liver Flukes) 300 Protozoan Parasites of Small Ruminants 304 References 307 8 Parasites of Hoofed Wildlife 309 Gastrointestinal Nematode Parasites are Important to Wildlife 313 Parasite Life Cycles 313 Transmission of Parasites 313 Control of Parasites in the Wild 314 Dewormer for Hoofed Wildlife 314 Description and Dosage Rate 317 Estimating Herd Size and Required Dose 317 Strategic Wildlife Deworming Program 317 The Modified Wisconsin Sugar Fecal Exam (see Figure 8.11) Plus a Submission Form (See Figure 8.12) and a Picture of the Most Common Eggs Found with Hoofed Wildlife Fecal Samples (See Figure 8.13) 318 Interpretation of Fecal Worm Egg Counts in Hoofed Wildlife Using the Modified Wisconsin Sugar Flotation Technique 318 Quick Assessment for Hoofed Wildlife Based on Fecal Worm Egg Counts 320 Gastrointestinal and Lung Parasite Infections Found in Small Ruminants and Hoofed Wildlife 321 Stomach Worms 321 Intestinal Parasites 324 References 333 Index 335