Introduction

Deworming is the systematic administration of anthelmintic drugs to eliminate internal parasites (helminths) from animals. Gastrointestinal and tissue parasites are a major constraint in livestock production, causing reduced growth, poor feed conversion, lowered milk and meat yield, reproductive inefficiency, and sometimes death. Regular and strategic deworming is therefore an essential component of animal health management and profitable livestock farming.

Importance of Deworming

• Improves growth rate and body weight gain
• Increases milk, meat, wool, and egg production
• Enhances feed efficiency
• Prevents anemia, diarrhoea, emaciation, and weakness
• Improves reproductive performance
• Reduces mortality in young animals
• Controls zoonotic parasites (public health importance)

Common Internal Parasites in Animals

1. Nematodes (Roundworms)

• Haemonchus, Ostertagia, Trichostrongylus, Strongyloides, Toxocara
• Cause anemia, diarrhea, bottle jaw, weight loss

2. Cestodes (Tapeworms)

• Moniezia, Taenia
• Cause digestive disturbances and poor growth

3. Trematodes (Flukes)

• Fasciola, Paramphistomum
• Cause liver damage, hypoproteinemia, bottle jaw

Principles of Deworming

• Correct diagnosis (fecal examination when possible)
• Selection of appropriate anthelmintic
• Correct dose according to body weight
• Deworming at proper intervals
• Avoid under-dosing to prevent drug resistance
• Follow withdrawal periods in food-producing animals

Common Anthelmintic Drugs Used

1. Benzimidazoles

• Albendazole, Fenbendazole, Oxfendazole
• Effective against roundworms, tapeworms, and some flukes
• Ashialben 2500 Bolus can be used.

2. Imidazothiazoles

• Levamisole
• Effective against nematodes
• Terazole 1000 bolus can be used.

3. Macrocyclic Lactones

• Ivermectin, Doramectin, Moxidectin
• Broad-spectrum, effective against internal and external parasites
• Albectin Bolus, Albection suspension can be used.

Deworming Schedule

Calves / Kids / Lambs

• First deworming: 2–3 weeks of age
• Thereafter: Every 2–3 months

Adult Cattle and Buffaloes

• 2–3 times per year
• Before monsoon
• After monsoon
• Late winter (optional)

Sheep and Goats

• Every 2–3 months
• Strategic deworming during high-risk seasons

Pregnant Animals

• Deworm in early pregnancy
• Avoid certain drugs in advanced pregnancy

Strategic Deworming

Strategic deworming involves treating animals at critical periods to break the parasite life cycle.

• Before onset of monsoon
• At the end of monsoon
• Before breeding
• Before parturition

This approach reduces pasture contamination and parasite load.

Conclusion

Deworming is a simple, economical, and highly effective health intervention in livestock management. Regular and strategic deworming not only improves animal health and productivity but also contributes to food safety, public health, and farmers’ income. Rational use of anthelmintics under veterinary guidance is essential for sustainable parasite control.