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New South Wales worms, flies and lice update - July 2015

NEW SOUTH WALES

Armidale: Rad Nielsen, Veterinary Health Research (rneilsen@vhr.com.au)

The trends noted in last month’s report have continued into July. Worm egg counts (WEC) have on the whole been low to moderate, interspersed with a few high counts (this week two properties in the Glen Innes district had individual mobs of sheep with mean WECs in the 2,500 epg range). The increased presence of Trich’s (Trichostrongylus or black scour worm) compared to recent years has also been an observation made, typically involving weaners. Without faecal culturing the nature of worm infections cannot be assessed, a fact which should not be overlooked by graziers when only conducting worm egg counts or more generally when drench selection is being made.

As previously noted, two-way combo drenches (Lev+BZ), even when combined with naphthalophos, typically fail to give adequate scour worm control in the New England region.

Lambing is fast approaching for sheep producers in the north of the state. I would encourage graziers to assess the worm status of their ewe flock in the 3–4 weeks prior to lambing. Even if a pre-lambing drench is routine practice, worm egg count and culture results will enable an assessment to be made as to the recent level of worm challenge (and potential threat of worms over the lambing period) and more targeted drench selection.

DPI NSW

Armidale: Stephen Love, Veterinarian/Research Officer (Parasitology) (stephen.love@dpi.nsw.gov.au)

Wormy weaners in winter

As mentioned in last month's issue of the news, high worm egg counts are being found in weaner sheep in various parts of NSW. Often but not always it is barber's pole worm (BPW). Worms don't disappear when it gets cold, even though the life cycle might stop ticking over, especially in the case of BPW. The infective larvae on pasture are relatively resilient and some of those produced in autumn will make it through to spring, despite frosts and snow.

Those who don't do regular WormTests (egg counts) might be unaware of high worm burdens that cause significant loss of production. 'Money down the drain, which makes regular WormTesting look like an investment, not a cost.

Unwittingly using ineffective drenches—very common—makes the problem worse. Another simple and cost-effective solution: do a DrenchCheck—test on the day of drenching and 10 days after.  Assume nothing, not even with the newer drenches.

Spring lambing ewes

It's too late to talk about preparing low worm risk paddocks for spring-lambing ewes because, in temperate or cold areas, this should start about the time of joining or a month earlier. The most important time to keep sheep off lambing paddocks is in autumn when it is still warm enough for worm eggs to develop and hatch.

But, back to the present and future. Keeping ewes in good nick—condition score 3.0+—in late pregnancy—day 90–150—improves ewe and lamb health and productivity, including worm control. Most ewes (see Your Program in WormBoss) will need a pre-lambing drench. Check that the drench worked with a DrenchCheck 10 days after drenching, and monitor ewes periodically after lambing to make sure worm burdens are under control, especially if you did not or could not do good lambing paddock preparation, or you don't know if the pre-lambing drench was highly effective.

Weaner paddock preparation

Start planning for weaner paddock preparation. See WormBoss Your Program; grazing management.

Liver fluke

On 'flukey' farms, the most important treatment time is when winter starts, around April/May. For those needing more than one strategic treatment, the next most important time to drench is around August. Yep, we are seeing resistance to flukicides emerging too. One way to check: get a liver fluke egg count 21–28 days after treatment. What animals can get liver fluke? More or less anything with warm blood and a heartbeat, certainly herbivores and humans. See WormBoss Your Program; liver fluke.

Weaner cattle?

A lot of spring-born weaner cattle were weaned and drenched at 6–8 months of age around the end of autumn.  Most worm impacts on weaners happen in the first 3–6 months after weaning.  Do you know the drench worked?   There is now a lot drench resistance in cattle worms too. (It's all good news here at Worm-Central J).  To do a quick check in cattle: do a WormTest on the day of drenching and again 14 days later.

 

NSW LOCAL LAND SERVICES

Riverina LLS

Young: Elizabeth Braddon, DV (eliz.braddon@lls.nsw.gov.au) and Rahul Shankar, DV (rahul.shankar@lls.nsw.gov.au)

The cold antarctic front has brought with it frigid overnight temperatures and cool day time temperatures. This has brought with it a slew of metabolic issues affecting stock, with worm issues taking a back seat for now. A few wormtests have been conducted by producers in our neck of the woods, and have averages of 20 epg–880 epg. The producer that is experiencing counts of 880 epg has had previous issues in relation to barber’s pole worm and due to the inability to spell paddocks and the previous summer not having hotter temperatures, larvae have survived, and the resultant adults are now causing issues to the lactating ewes. An appropriate drench has been instigated and this should hopefully alleviate production issues until we can look to clean up this paddock later this summer. 

Producers have been reminded of the need to be mindful of weaning paddocks, and to have weaners drenched at 12–14 weeks of age and moved onto low risk pastures. Producers have also been reminded to undertake regular WormTests, rather than arbitrarily drenching where there is no need to. 

Editor's note: many of the District vets were away at the time articles were required, so we have few contributions this month.