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Victoria worm update - October 2013

Andrew Whale, Livestock Logic, Hamilton (a.whale@livestocklogic.com.au )

A very timely rain event in South Western Victoria has ensured continued quality pasture growth well into November and more over the next 1-2 weeks will guarantee bulk feed being available in early Summer with the opportunity for many to conserve feed and refill haysheds and silage pits.

Livestock Logic worm egg count averages have increased in October. This is likely to be a reflection of increased egg counts from new season lambs as well as large numbers of Spring lambing ewes getting WEC’s pre lamb marking where there have been some elevated counts in these ewes despite pre lambing drenches. A warning for anyone still to lamb mark – do a WEC on the ewes. While egg counts have risen we have had less cases of mortality and significant clinical signs of worms in October compared with September. This is a reflection of better feed availability and improved environmental conditions for sheep.

Table 1: Livestock logic’s average worm egg counts >200 epg for all mobs for the months from June until September.


Month

% counts >200 epg

June

12%

July

21%

August

28%

September

34%

October

41%


Egg counts in November are an important tool as they can be used to fine tune your Summer drenching program. It is impossible to visually judge high, medium or low egg counts at this time of year, yet they have quite different strategic requirements. High counts require prompt drenching for production purposes, medium can be delayed until December to reduce likelihood of second Summer drench and low count sheep can be re-monitored 4-6 weeks later to see if a 1st Summer drench is required.

The following is a guide only that may require modification for individual districts.

Nov adult sheep drenching trigger levels (guide only)

               < 150              Repeat WEC in Dec

                150 < 300     Delay 1st summer drench til Dec

                300+              Drench promptly  

Now is the ideal time to perform a drench resistance test on your weaners. Get a Worm Egg Count done – if it is over 300 epg, seek advice before you drench on how to find out your property’s drench resistance status.


Tricia Veale, Benalla (triciav7@bigpond.com):

We have had a moderate amount of rain here in North Eastern Victoria with 52 mm for September but only 19 mm so far for October. Dams are still full but the local area is superficially very dry. Farmers are concerned about crop survival as there is often a frost in the early morning.

Worm numbers are still at moderate to high levels in most areas. It’s a good idea to check this by getting worm egg counts done before drenching. Many farmers are routinely testing their sheep which helps to avoid unnecessary drenching.

If you are on a property where there is a history of Liver Fluke being present, suggest that you get this tested as they are still active in many places.

Tapeworms have been noted to be active in sheep. Bladder Worm (Cysticercus tenuicollis) is also evident, the fluid filled cysts have been found in some sheep carcasses. Dogs can acquire this tapeworm by eating sheep offal that contains the cysts. These do not infect the dogs, they are only the carriers. Dogs pass tapeworm segments containing thousands of eggs onto the paddock, where the sheep consume them with the grass.  So ensure that your dogs are not fed fresh sheep meat.

Barber's Pole worm (Haemonchus contortus) is now active, and it is one of those worms that is not being identified early enough. The mature worms lay many thousands of eggs that allow numbers to build up very quickly. This worm lives in a sheep's stomach and sucks blood, causing anaemia and weight loss.

Problems have arisen on some local properties where sheep from dry areas have been introduced onto damp paddocks. They very soon pick up worms and the immature stages cannot easily be recognised by faecal egg counts.

A total worm count from the intestines of a dead animal will give an indication of the worm burden and the types present.