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Tasmania worms, flies and lice update - February 2017

Tasmania WormBoss Worm Control Programs

Tasmania WormBoss Drench Decision Guides

Sheep

Goats

Sheep

Goats


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

Caesar was stranded on the shores of Gaul, waiting for a favourable breeze to set out for England. With him was Dooley, a feckless Celt with similar intentions for Ireland. One morning they wandered to the shores of the Channel, Caesar threw some grass into the air—like Mathew Lloyd lining up for a goal—and proclaimed: “Dooley, the wind has changed.”

“Jaysus, Caesar,” replied Dooley, “How will we recognise it if it has changed?” Sadly, Dooley did not remain feckless and Ireland is what it is today. The value of an impact sire is for another forum.

A long-winded way of saying the wind has changed in Tasmania. Firstly, the wind has gone, or at least we’ve had some calm days. The weekend when NSW sweltered and burnt, the Tasmanian Highlands had a slight sprinkle of snow. Secondly, worm egg counts (WECs) are starting to move. The last month has been dry and in the last two weeks temperatures have dropped a deal, with the mornings having a distinct autumnal feel. Paddocks are dry, but mostly still have a good cover, and the grain harvest is in full swing.

WECs in finishing lambs and Merino weaners are on the up. Several clients have had WECs greater than 1000 eggs per gram (epg) in lambs on fodder crops. Interestingly, the lambs were growing well and had little scour. Larval diffs (worm typing can be requested with a WEC) showed 85% Trichostrongylus and some Haemonchus. At this level I would have expected some scouring. There are 3 take-home messages:

1. Monitor relentlessly. There is enough ground cover for contamination to survive, and an output of 1000 epg will lead to huge contamination which will bite us in the autumn.

2. It is time for a second summer drench for all sheep on perennial pasture. All areas of the state will need it this year.

3. High egg counts in finishing lambs may include Haemonchus. Get a larval differentiation (ask your testing laboratory) if you have a high count with little scouring.

Goats: A colleague from the south of the state reported Haemonchus in a mob of meat goats. This is not unexpected, and it shows that that the notion that Haemonchus is a warm-summer worm is overrated. Goats without access to browse are worm factories.

Attached are two pics: same farm adjacent paddocks. The “bare” paddock is what we see in Victoria and South Australia every year. Without moisture and given some heat, larval survival would be relatively short. In Tasmania the weather has cooled enough that the larvae might well survive through to the autumn. Hence the need for a second summer drench. Paddocks like this will be protected well into the autumn.

The second paddock has a lot more cover, and is typical of late summer/early autumn Tasmanian paddocks, particularly in the north. On this paddock we can expect the larvae to have enough moisture at ground level to be active. Sheep, particularly weaned lambs, would recycle the worms and make a net contribution to paddock contamination, because as the weather cools, larval survival, even outside the pellet, is OK. This explains why the double summer drench does not work as well here as in other parts. Nevertheless, a second summer drench does reduce the carryover of larvae to the autumn when things really get going.


 1. Bare paddock but larvae might well survive through to the autumn
1. Bare paddock but larvae might well survive through to the autumn
2. Adjacent paddock on the same farm with long dry grass cover. Larvae could be expected to have enough moisture at ground level to be active
2. Adjacent paddock on the same farm with long dry grass cover. Larvae could be expected to have enough moisture at ground level to be active