Anthelmintic resistance in sheep and goat farms on Peninsular Malaysia

The faecal egg count reduction test (FECRT) was conducted on 39 sheep farms and 9 goat farms located in Peninsular Malaysia. The anthelmintic groups u sed in these tests were the benzimidazoles, levamisole, the benzimidazole/l evamisole combination, macrocyclic lactones and closantel. Results indicate d that the prevalence of resistance to the benzimidazole group was high, wi th approximately 50% of the sheep farms and 75% of the goat farms having re sistant nematode parasite populations present. Resistance to levamisole, cl osantel and ivermectin was also detected. Differentiation of the infective larvae derived from faecal cultures indicated that by far the most predomin ant parasite species was Haemonchus contortus. (C) 1999 Elsevier Science B. V. All rights reserved.