The survival and fecundity of buffalo flies after treatment of cattle with three anthelmintics

Two anthelmintics with known insecticidal action (ivermectin and closantel) and one with no recorded effect on insects (levamisole) were tested to evaluate their effects on buffalo fly (Haematobia irritans exigua). Blood from animals given closantel or levamisole had no significant effect on mortality of buffalo flies in an in-vitro assay. In contrast, blood from animals given ivermectin showed a dose-dependent effect on the mortality of buffalo flies. At 24 h after one injection of the recommended dose of ivermectin, 98% of the flies applied to cattle in an in-vivo assay are killed. Blood from cattle injected with ivermectin killed 95% of flies 8 d after injection and still killed 15% of flies at 18 days after injection. Surviving flies laid almost no eggs and this effect on flies was significant up to 33 d after injection. The results indicate that ivermectin may be useful to control buffalo fly populations in the field.     

Comparison of tiletamine-zolazepam-ketamine and tiletamine-zolazepam-ketamine-xylazine anaesthesia in sheep

Summary The anaesthetic effects of intravenous tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg (TK) and tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg-xylazine 0.11 mg/kg (TKX) were evaluated in six wethers. Heart rate, respiration rate, arterial blood pressure, and the electrocardiogram were monitored during anaesthesia. Analgesia was tested by electrical stimulation in the left flank. Atropine (0.03 mg/kg) was given intramuscularly before induction, but after recording of baseline heart rate and respiratory rate. The duration of analgesia was 28.7 ± 6.9 min with TK and 82.8 ± 26.6 min with TKX. Heart rate increased significantly within 5 min after TK or TKX administration. Respiratory rate remained unchanged after TK administration, but increased significantly from 5 to 45 min after TKX administration. Arterial blood pressure decreased significantly at 15 min with TK and 30 min with TKX. Sheep remained recumbent for 201 min with TK and 166 min with TKX. All recovered uneventfully. We conclude that either TK or TKX may be used for anaesthetising sheep.