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Victoria worms, flies and lice update - June 2014

Hamilton: Steve Cotton, Livestock Logic (s.cotton@livestocklogic.com.au)

A fantastic start to the season has seen excellent opening rains, and the continuation of mild weather has seen improved perennial pastures in areas around Hamilton growing at 40 kg/ha/day. This is equivalent to September–October pasture growth rates, yet surprisingly, stock growth rates, particularly in weaner calves, have been stagnant. Cooler weather and recent strong southerly winds certainly emphasises that winter in finally upon us, albeit a month late. Rainfall for Hamilton Airport to the end of May 2014 has been 186 mm, with 75 mm and 51.2 mm falling in April and May respectively. So far for June, 56 mm of rain has fallen. Comparing these amounts to 2013, with 12.6 mm, 50.6 mm and 72.8 mm for April, May and June respectively, it is clear to see the impact 60 mm of rain in April can make to the start of a season!

The following table represents sheep that have had worm egg counts >200 epg from Livestock Logic worm laboratory in June up to and including 24th June 2014.

Class of sheep

% requiring drenching June

Mature age sheep

11%

2012 drop maidens/hoggets

31%

2013 drop weaners

35%

 

Typically we see younger sheep (<12 months of age) with higher WECs and therefore, priority in WEC monitoring should be given to these animals.

The table below, shows historical data for mature age and weaner sheep for the past 6 years that have had WECs  >200 epg. Data has been collected by Dr David Rendell and Livestock Logic.

Year

Mature Age

weaners

June

June

2009

21%

30%

2010

11%

45%

2011

27%

54%

2012

20%

30%

2013

10%

13%

2014

11%

35%

 

Heading into winter it is important to continually monitor WECs not only in adult sheep pre-lambing but also spring 2013-drop weaners. It is particularly important for weaners to gain exposure to worms to gain some host immunity, however, exceeding threshold levels of around 200–250 epg will be hampering stock performance and productivity. If weaners are in good forward condition (i.e CS 3+ and live-weight targets have been met), delaying drenching until WECs reach about 300 epg will be beneficial.

At WEC levels up to 250 epg in mature age sheep, the benefit of drenching will depend on their condition score, lambing date and age, however, when levels exceed this trigger point a drench is usually warranted.

It is critically important to monitor sheep and perform regular WECs. If your WEC levels are low, yet sheep are scoury or visually looking poor, consult your veterinarian. With winter WEC monitoring, test lambs five weeks post drenching and then fortnightly thereafter and for mature age sheep, test 6–8 weeks post drench and then 4–5 weeks thereafter. For pregnant ewes, endeavour to perform a worm egg count 3–4 weeks out from lambing start date to evaluate their need for a drench. The results from this WEC and from previous WECs provide a sound basis for discussion with your consultant or veterinarian on how to best manage these ewes over the coming weeks.

Benalla: Tricia Veale (triciav7@bigpond.com)

In this area of North Eastern Victoria we have had some great rains. There was 75 mm in May and 48 mm so far for June. The paddocks are very green with plenty of feed, but the cattle are still enjoying being fed hay.

Worm egg counts are now at quite moderate to high levels generally. In this area there have been reports of sudden deaths of one to two percent of mobs of sheep. It’s essential to test the worm levels in animals, especially in paddocks where ewes have young lambs.

This is a good season for worms to multiply rapidly. The sheep consume the worm larvae and they are then present in high numbers four or five weeks later.

That said, it's also important not to drench animals unless it is needed to avoid the increasing of drench resistance. So do test first!

A large number of properties where Liver Fluke, Fasciola hepatica, have been cycling have had positive test results. Fluke now appear to be active in many localities in this area.

Coccidian oocysts of mixed Eimeria spp. are now very evident in young calves, cria, kids and lambs. If your young animals are scouring badly we suggest that you send in some samples for examination. You can then determine if large numbers of coccidia or worm eggs are present.

Also keep a check on young lambs to make sure they are not shedding Moniezia sp, tapeworms or eggs.

This way you can be sure of giving animals the correct treatment.