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Victoria worms, flies and lice update - March 2021

VIC WormBoss Worm Control Programs

VIC WormBoss Drench Decision Guides

Sheep

Goats

Sheep

Goats

Hamilton: Lexie Leonard, Livestock Logic (l.leonard@livestocklogic.com.au)

Since the last report there hasn’t been much of a change in worm outlook for the south-west. South of Hamilton, persistence of green pick and small rain showers will keep worms cycling in the pasture. North of Hamilton has been marginally drier, and there have been areas that have managed to get an effective second summer drench. For most areas however, drenching from clinical signs and worm egg count (WEC) results is the most effective way to keep pasture burdens low. It is important not to stop monitoring WECs, especially for young sheep as there will still be spiking of worm burdens post rain throughout autumn.

Preparation to keep in mind over the next three months:

  • Lambing paddocks for late Autumn/Winter will be even more critical this year as we generally anticipate poorer worm control over summer and autumn.
  • Pre-lamb drenching timing and drench choice will be critical and needs to be matched to mob and paddock risk level.
  • Winter paddocks for last year’s lambs need to be planned ahead to minimize risk of winter dysentery and parasite burdens.

Barber’s pole worms are still popping up around the district in isolated cases, if you have sheep on green pick following rain keep a close eye for clinical signs of barber’s pole — bottle jaw and weak sheep are the most common signs, followed by apparently sudden death*. Scours do not occur with barber pole infections so is not a reliable sign of a barber pole worm burden.

Flies have been mostly kept in check with cooler temperatures, and we don’t anticipate another fly wave with lower temperatures expect for the next few weeks, but isolated cases are to be expected. As usual, lambs and weaners are the most susceptible so it may be worth considering a fly prevention if previous doses have worn off.

*Editor’s note: Death from barber’s pole worm is not a sudden occurrence (unlike diseases such as pulpy kidney). It takes some weeks for a severe cumulative blood loss from Haemonchus to become terminal and the sheep show no signs of illness while they are left undisturbed until they almost run out of red blood cells to carry oxygen, then bottle jaw may become evident and they separate from the mob and death may occur after a few more days. However, if they are mustered, the stress of extra activity may require a lot more oxygen than their blood can carry; in these cases collapse and death may appear sudden, but worm egg counts a couple of weeks earlier would likely have indicated an already high burden.

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