Despite receiving some much needed rain in mid-October, graziers in the New England/North West region continue to battle with drought conditions. The scarcity of meaningful rainfall events will have limited the spring development of worm larvae on pasture, the only likely benefit from such a scenario. Worm monitoring submissions in October continue to show variable worm burdens in all classes of sheep; from zero to sub-200 epg mean in lactating ewes prior to lamb marking, through to sheep with mean worm egg counts in excess of 1500 epg within 6 weeks of their last drench. Once again this highlights the variation that occurs between properties and the need to be aware of the worm status of sheep at all times of the year.
A vaccine for Haemonchus (Barber’s Pole Worm) has very recently been released for use in the New England region. Available on a restricted basis for the 2014/15 Haemonchus “season” and for use in lambs only, it is hoped that by next spring the registration will cover all ages of sheep and dose availability will be non-limited. Named “Barbervax”, the vaccine has the potential to become a key component in the management of Haemonchus. By stimulating the production of antibodies to the parasite’s gut enzymes (leading to starvation and death), Barber’s Pole worm burdens in sheep will be significantly reduced, leading to direct productivity benefits and reduced reliance on anthelmintic treatments. Vaccinated sheep also have greatly lowered worm egg counts (Haemonchus only), leading to a significant reduction in pasture contamination. The cumulative effects of this over time on properties conducting entire flock vaccination has the potential to be “game changing” in respect to the management of the parasite and its future impact on flock health.
In Young and its surrounds we have had no clinical investigations for worms this past month. The few worm egg counts we have received have been good barring a few mobs in one property that were having high counts, but were likely attributed to scour worm over anything else. An appropriate drench was recommended and the problem appears to have resolved with that.
On a disease investigation at another property the incidental finding there was large amounts of barber’s pole worm that were not causing any production issues. This producer had not drenched in over a year and was advised to go with an appropriate drench to avoid any issues that may arise down the track.
For the Narrandera and Hay regions the worm egg counts that have been done are generally low to very low.
Producers are reminded that now would be an excellent time for their first summer drench.
Any worm-related disease is being masked by the tremendous bulk of quality green feed at present. Sheep are in good condition, with fewer scouring than normal for this time of year. But there is a potential problem. Worm egg counts are starting to rise, with about half the properties tested showing substantial proportions of Haemonchus (barber's pole worms). Almost weekly rainfall will ensure many of these eggs will hatch, so keep watch for tell-tale signs of weakness and anaemia.
Just to make life interesting though, young sheep have collapsed and died on a number of properties with symptoms typical of barber’s pole worm infection. They were in good body condition, with very pale skin (anaemia). Post mortem examinations showed they died not from barber’s pole worms, but from infectious anaemia.
This condition occurs within a couple of months of any husbandry procedure that may damage skin. Recent cases occurred in hoggets following shearing, and in lambs following marking and mulesing.
â€‹Infectious anaemia of sheep involves a microscopic organism that destroys red blood cells, leading to profound anaemia.
When finding dead sheep with anaemia, our first reaction is to drench them for barber’s pole worm. This handling only leads to more deaths if infectious anaemia is the cause. Affected mobs are best left alone on good pasture to recover.
â€‹With plenty of barber's pole â€‹around in sheep at present, an autopsy is essential to an accurate diagnosis and effective treatment.
With so much green feed about, don't be tempted to leave lambs on ewes ‘just a bit longer’. Worm levels in un-weaned lambs rise significantly and growth rates suffer if you do.
We are having a brilliant spring here around Braidwood/Bungendore. Only a few worm tests have been done, with some high barber’s pole worm counts together with medium black scour worm counts. The barber’s pole situation is the most worrying but many producers may be able to control it when they give their flocks their November drench.
The season in the Murray region has closed with a bang. The good subsoil moisture from the wet autumn and winter has allowed crops and pastures to continue growing despite the dry surface.
With the drier weather there have been few parasite problems: no clinical problems have been investigated, and only a few worm egg counts and those few mostly low counts.
Please note the new DVs for the Murray region: Linda Searle, Mark Corrigan and Scott Ison.
Some worm counts have been done in the area, with totals up to 800 epg, and mainly Haemonchus (95–98%) but one differential showed 55% Haemonchus and 15% each of Trichs, Ostertagia, and Oesophagostomum.
We have had a reasonable drop of rain so this should help both the pastures and the worms.
Northern Tablelands LLS
Our season on the Northern Tablelands is tough for survival of sheep and worms.
We saw clinical cases of barber’s pole worm on a few properties very early in the spring, which highlighted either how tough larvae are or how mild the winter was. This was an exception rather than the normal.
Currently survival of worm eggs on the ground should be poor, so hopefully one benefit of the dry spring is a reduction in larval contamination on pasture. With a 40% chance of average rainfall between now and Christmas it looks like tough times for worms and sheep and cattle and goats and farmers and .........
Only three worm tests submitted this month, but one result with an average of 1572 epg (91% Haemonchus) was unexpectedly high considering the dry conditions. In saying this, the result was 4 times higher than on the other end of this property where there have been no showers at all.
Of concern is the drench that this producer intends to use—a new combination drench that he received free through a promotion when purchasing several drums of a fly and lice treatment. This drench is certainly overkill for us in the west but is the obvious choice when it's free!