Tasmania worms, flies and lice update - June 2018

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

Greetings from the deep south.  We’ve had enough rain over a big enough area that most sheep producers are looking forward to a fair to good winter.  The exception is the middle and upper Fingal Valley, where the paddocks still look distinctly deficient. 

We are in the parasitic doldrums.  Dry sheep are fine.  Merino weaners are wormy.  Same as last month.  The World Cup is worth watching, while the rugby is problematic.  Wait until next month and we can discuss pre-lambing options.

Just a word on prime lambs:  the vast majority of lambs have been finished.  However, most producers still have the troublesome “last few hundred” that pox paddocks and consume resource that would be better saved for pregnant ewes (or shut up for lambing).  It gets worse when the fodder crops they have been on get ripped up for winter crops, thereby placing additional pressure on other paddocks.  The simple suggestion is to have a planned quitting date.  For most people this should be late June.  Think of quitting the slow ones to one of an increasing number of specialised lamb finishers who are scrambling for lambs in late autumn and winter.  Just because they have not cut their teeth does not mean they are a great asset to you.

Organic Worm Control:  This is dangerous territory for me as I am inherently of the view that organic production (sheep and goats) and high rainfall are poor bedfellows.  It’s also fair to say that the few times I’ve worked with organic producers has been to solve an existing problem.  There are some good notes on the WormBoss website, but herewith are some additional thoughts:

• None of the allowed treatments do enough to relieve heavily parasitised sheep and goats.  The one exception is magnesium flurosilicate for lice control.
• Given the above, parasitised sheep and goats should be treated with a conventional anthelmintic or sold to someone prepared to do so.  Doing nothing is not an option.
• So, it’s obvious that prevention is imperative, and this involves a deal of grazing management:
  • Reduce your stocking rate to maybe 2/3 that on conventional farms.  This should allow long periods of pasture spelling (it needs to be at least 5 months in the autumn/winter and maybe 3 months in the spring and summer).  This takes discipline.  Spreading the animals out may make nutritional sense, but will do bugger all to reduce effective contamination.
  • Have 50% of your grazing pressure as cattle and alternate grazed areas on a 6-monthly rotation.
  • Quit finished lambs as early as possible to reduce winter contamination.
  • Utilise bush blocks, particularly for goats, being mindful of nutritional adequacy.
  • Prepare winter paddocks with a modified “smart grazing” using cattle rather than sheep, provided the cattle have the body reserves to lose.