[Anthelmintic control of multiresistant nematodes in the gastrointestinal tract of imported goats]

Multiple resistant strains of Ostertagia and Trichostrongylus were detected in a flock of cashmere and angora goats imported from New Zealand. The ED50 values detected by in vitro EHA test were from 0.27 to 0.36 micrograms/ml (while the reference value of sensitivity is 0.10 microgram/ml TBZ). Multiple resistance to all the types of currently used anthelmintics was confirmed by in vivo FECRT, when the efficacy of recommended doses was lower than 90% (albendazole 74%, levamisole 86%, ivermectin 83%). Two control schemes were investigated. In the simultaneous application of anthelmintics in the double or triple of recommended doses (0.4 mg/kg ivermectin s.c., 30 mg/kg levamisole and 20 mg/kg albendazole p.o.) was effective. Examination of goats 7 and 8 months after treatment revealed the repeated presence of multiple resistant gastrointestinal nematodes. It is the first published case of intercontinental transfer of resistant strains of nematodes when importing small ruminants.