Results of diagnostic milk samples sent to the wallaceville animal health laboratory

The occurrence of a field strain of Haemonchus contortus resistant to thiophanate is reported for the first time in New Zealand. In a controlled anthelmintic trial with experimentally infected animals, thiophanate at 50–100 mg/kg had no appreciable effect on the Haemonchus burden. Albendazole reduced faecal strongylate egg counts by 95% in animals with naturally acquired infections.