< Back to Outlooks Listing

Tasmania worms, flies and lice update - May 2018

Tasmania WormBoss Worm Control Programs

Tasmania WormBoss Drench Decision Guides

Sheep

Goats

Sheep

Goats


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

You don’t need me to tell you of the major weather that hit Hobart and the south on 11th of May. Apart from the cars floating down the capital’s main street, the lower south-east received exceptional rain, and there were good falls in the Derwent Valley and the droughted Fingal Valley. Most other areas received useful top-ups. While we’ve also had a few decent frosts, the ground is warm enough to get good prewinter pasture growth. All things considered, it’s looking good but not exceptional.

Some merino weaners are really under the pump. Many have been on short rations and bodyweights are marginal. The rain in the last month has kicked the worms into gear, and we’ve seen some very high counts. On some properties merino ewes are also starting to dag-up a bit. Whether you drench to the calendar, or use worm egg count (WEC) triggers, a few WECs are useful to gauge the amount of contamination being laid down. The warning is that this year will probably be a good one for worms on merino places, in spite of the dry summer. Be prepared. The few people who use smart-graze to prepare winter grazing are unlikely to have enough pasture growth to stock these paddocks, so hold off a few weeks even it involves an additional drench. The great unwashed who do not “smart-graze” should consider doing it.

Prime lamb ewes are happily doing their thing, even if a bit lighter than last year. Again, monitor to at least see what burden the pastures will carry into winter. Some finishing lambs are struggling. Grass dominant paddocks are mostly contaminated by now, and the legume circles have shut down. Lambs should be monitored aggressively or drenched routinely as described in the February newsletter.

As promised, time for the annual fluke sermon. At least three of the abattoirs used by Tasmanian producers (2 sheep, 1 cattle) provide timely feedback on what’s inside the animals. Surprising what you find when you look, but it’s likely that the fluke range is extending beyond where it is usually found. A lot of this is due to irrigation. Attached is a picture of an irrigation ditch known to sustain fluke. Two things are commentable: firstly, it’s really not much of a stream, is it? Fluke habitat is often just a manky drain or a hillside spring rather than the overflow of Lake Argyle. Secondly, notice the wee frost?


Habitat of the liver fluke snail in winter. Source: Paul Nilon
Habitat of the liver fluke snail in winter. Source: Paul Nilon

May/early June is the ideal time for a fluke drench as frost stops transmission. Only the most heavily contaminated areas in the highlands are likely to need therapeutic drenches between February and May. The next drench should be in late winter or early spring to kill any fluke picked up after the May drench.

Drenching sheep exposed to flukey paddocks is a no-brainer. Sheep of all classes are vulnerable to even modest fluke burdens. Cattle are more problematic, as well-nourished adult cattle are robust to fluke parasitism. They should only be drenched in three circumstances: young cattle expected to grow well should be treated; light adult cattle in chronically infected areas should also be treated (mostly the river headwaters and high country); in the unlikely event that there is little game on your property treating cattle will reduce the contamination to which sheep will be exposed.

Now for a topic that is parasitological, if not worms. The other day I hit a crow, remarkable as in 45 years of driving it had not happened before. The unfortunate Corvid will provide endless wing-cases for pot-scrubber nymphs (not a sylph-like domestic, but a trout fly - see picture). Clients also report kangaroos that you can walk up to in the paddock: kangaroos in the top paddock with kangaroos in the top paddock, so as to speak.


Pot-scrubber nymph. Source: Paul Nilon
Pot-scrubber nymph. Source: Paul Nilon