Tasmania worms, flies and lice update - July 2020

Perth: Paul Nilon, Nilon Farm Health (pandonilon@bigpond.com)

The worm front is much the same as last month, so no need to repeat things endlessly.  All the planning for lambing should now be in place. Despite the wet year, we’ve not seen any large-scale breakdowns due to black scour worm. Presumably, this reflects the abundant pasture and good BCS of nearly all classes of sheep.

More on Fluke: Apropos of last month’s column, some more on the imported fluke problem: I was fairly convinced that the sheep had not been treated with triclabendazole. Turns out I was wrong:

• The vendor’s manager contacted me to discuss the problem and was able to provide all relevant info.
• My clients retreated with TBZ and had live fluke a week later.

This was a case of monumental resistance. I have suggested the vendors have a fluke reduction test done (talk to Matt Playford at Dawbutts), but as the vendors are not regular clients, I have little leverage. 

Alternatives to TBZ for fluke in sheep:

            Closantel:              ESI 60 days

            Oxyclosanide:       ESI 14 days

(Cattle are fortunate to have additional chemicals, nitroxynil and clorsulon, available for fluke, but these are not registered for sheep.)

So, this begs the question: why have I not listed albendazole? Firstly, it kills adult fluke only.  Secondly, and this is just a hunch, I would be concerned that there may be some commonality of resistance between ABZ and TBZ.  Maybe somebody can enlighten me.