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Comparison of the efficacy of macrocyclic lactone anthelmintics,either singly or in combination with other anthelmintic(s), in nine beef herds in southern NSW |
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| Authors: | MB Allworth B Goonan JE Nelson G Kelly SR McGrath RG Woodgate |
| Institution: | 1. Fred Morley Centre, Charles Sturt University, Wagga Wagga, New South Wales, 2678 Australia;2. School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, 2678 Australia;3. Boehringer Ingelheim Animal Health Australia Pty. Ltd., Macquarie Park, New South Wales, Australia;4. Fred Morley Centre, Charles Sturt University, Wagga Wagga, New South Wales, 2678 Australia
School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, 2678 Australia Gulbali institute, Charles Sturt University, Wagga Wagga, New South Wales, 2678 Australia;5. School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, 2678 Australia Gulbali institute, Charles Sturt University, Wagga Wagga, New South Wales, 2678 Australia |
| Abstract: | Anthelmintic resistance (AR) is a well-recognized challenge in farmed ruminants. The use of anthelmintics in combination is one of the strategies recommended to slow the rate of AR development. Two studies were undertaken in 2017 and 2019 to assess the efficacy of single-dose macrocyclic lactone (ML) anthelmintic and ML combination drenches. In total, 11 Faecal Egg Count Reduction Trials (FECRTs) were set up in 10 different beef herds, with results available from 10 of those FECRTs (9 herds). AR to a single ML anthelmintic was detected in all 9 herds, with resistance to Cooperia and Haemonchus spp on 9 farms, and resistance to Ostertagia and Trichostrongylus spp on 2 farms. In contrast, for the ML combination anthelmintics, all FECRTs resulted in efficacies of 99%–100%. The results suggest that cattle producers should strongly consider using combination drenches in their herds in preference to single actives. |
| Keywords: | animal welfare cattle parasitology ruminant physiology |