Trichostrongyles
Trichostrongyles are a type of gastrointestinal nematode (roundworm) that can cause significant health issues in sheep, particularly in lambs. These parasites are commonly found in the intestines and can lead to severe weight loss, diarrhea, and even death if not managed properly. Understanding the symptoms, treatment, and prevention of Trichostrongyles is crucial for maintaining a healthy flock.
Symptoms and Diagnosis 🩺
Trichostrongylosis typically affects lambs in the autumn or winter. Here are some common symptoms to watch out for:
- Dark-colored, foul-smelling diarrhea
- Weight loss
- General weakness and lethargy
- In severe cases, death
Diagnosis is often made through a combination of clinical signs and faecal egg counts (FEC). However, it's important to note that during certain stages, such as when larvae are encysted in the gut wall, FEC may not be reliable. In such cases, a post-mortem examination may be necessary.
Treatment 💊
Treating Trichostrongylosis involves the use of effective anthelmintics (wormers). The five major anthelmintic groups include:
- 1-BZ (White): Albendazole, Fenbendazole
- 2-LV (Yellow): Levamisole
- 3-ML (Clear): Ivermectin, Moxidectin, Doramectin
- 4-AD (Orange): Monepantel
- 5-SI (Purple): Dual active (Derquantel and Abamectin)
It's essential to consult with your veterinarian to choose the right treatment and to minimize the risk of developing anthelmintic resistance. Regular FECs can help monitor the effectiveness of the treatment.
Prevention 🛡️
Preventing Trichostrongylosis involves several strategies:
Grazing Management
- Rotate pastures to avoid overgrazing and reduce the build-up of larvae on the pasture.
- Graze young lambs on clean pastures that have not been grazed by sheep in the previous year.
- Use mixed grazing with cattle to disrupt the life cycle of the worms.
Targeted Selective Treatment (TST)
TST involves treating only those animals that show signs of infection or have high FECs. This approach helps reduce the risk of developing anthelmintic resistance by leaving a portion of the worm population unexposed to treatment.
Quarantine New Arrivals
Quarantine and treat all incoming sheep to prevent introducing resistant worms into your flock. A period of at least three weeks isolation coupled with a quarantine drench is recommended.
Regular Monitoring
Regular FECs can help you monitor the worm burden in your flock and the effectiveness of your treatment program. This allows for timely interventions and adjustments to your worm control strategy.