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Tasmania worms, flies and lice update - October 2015

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

Having just flown the length of this brown land, it certainly is brown. And Tasmania is not a speck of green contrast. The equinoxial gales have blown relentlessly, and October’s average temperature to date is higher than the long-term December average. If that’s not enough, there was a ball-tearing frost on Sunday morning and perhaps this morning. The southern Midlands and east coast are pretty ugly, the northern Midlands are OK, and Bothwell/Derwent Valley fair to middling.

Lamb marking is in full swing. Worm counts have remained low and unless you have cause for concern (light, dry ewes and lambs or very high egg counts) you should not need a lambing drench. Pay attention to tail length while marking lambs, and if you are mulesing, use pain relief

Now, on recent trip to Port Douglas (Did you enjoy your holiday? Yes I did: thank you for asking), I was eating seafood in a park next to the Stella Maris church. Amongst the manky chips I found cod, and became a prawn again Christian. Even on holiday, I’m excogitating on things parasitological. On this occasion, the reverie was directed towards the poxy season. With green grass running short, wean as early as you can. It’s better to have precious, green grass processed through the lamb’s gut rather than through the ewe’s. If the only green grass is on the lambing paddocks, so be it. Drench back onto those paddocks and monitor vigorously.

It’s also time to consider drench rotation. Because combinations (particularly abamectin triples) are now the norm, rotation options are limited. The price of our new actives (derquantel-Startect® and monepantel-Zolvix®) makes it unlikely that producers will rotate to them for protracted periods. However, it is very important to use them. Even infrequent use will slow resistance to other actives. Standard recommendation is to use one or the other at least once a year. As you must have a working drench for your strategic drenches, using a new compound for the first or second summer drench is a good opportunity to get them in the system. Just remember to plan ahead for lamb sales and watch the Export Slaughter Intervals.

Should also mention Haemonchus (barbers pole). A client with ewes on paddocks irrigated through the summer and autumn had some post-lambing losses (of ewes) with high egg counts and no scouring. Seventy percent of larvae were Haemonchus. In the northern Midlands, ewes that spent winter and spring on irrigated pastures should have some WECs. If you have a high count with no scouring, get a larval differentiation to identify the type of worms present, and if it comes back with Haemonchus, seek expert advice.