NSW WormBoss Worm Control Programs
NSW WormBoss Drench Decision Guides
There has been some good (but somewhat patchy) storm rain across the New England region in the past month. This will have triggered worm egg hatching and larval development, in turn placing sheep at risk of haemonchosis, in particular. There have been reports of ewe and lamb deaths attributable to barber’s pole worm in the Guyra and Walcha districts in the first two weeks of December, an early warning for sheep producers of the need to be vigilant over the coming months in respect to worm management and surveillance.
Some high individual mob worm egg counts have been identified at the VHR Laboratory in recent weeks. Of particular note was a mob of ewes and lambs in the Glen Innes area with a mean worm egg cCount (WEC) of 5,600 eggs per gram (epg) only one month post an effective drench. Not all results are high, however—a significant percentage of laboratory submissions have recorded low to moderate WECs (less than 500 epg mean).
Weaning is the next major sheep management activity for a lot of graziers in this region. A weaning drench is typically required for lambs (generally best to use a genuinely effective broad spectrum product), before placing on prepared “clean” paddocks. A ewe treatment may potentially not be required at weaning (depending upon prior worm treatments)—worm monitoring will enable this decision to be made.
Barbervax® (Haemonchus vaccine) is being administered in the New England region for its second summer. It has now been approved for use in adult sheep, enabling complete flock application. Good results were achieved with the vaccine in its launch season. I certainly see Barbervax® as being a key component of worm management in Haemonchus endemic areas in the future.
I wish all Paraboss News readers an enjoyable Christmas and wet 2016!
No worm tests have been submitted for sheep. However, worm tests have been conducted by two goat producers who have had stock deaths over the last two months.
An intensive goat enterprise in the southern part of the Western Division had around 10 goats die out of 90 goats, all reported as sudden death. Post mortem of three goats revealed no gross abnormalities and the goats were described as being in "pristine condition". Laboratory investigation of the abomasal wall revealed embedded nematode parasites. The worm egg count (WEC) from this goat was 30,000 eggs per gram (epg), with an average over five goats of 10,616 epg. A larval differentiation was not performed but coupled with anaemia and bottle jaw in one animal, haemonchosis was diagnosed.
A second goat enterprise in the northern part of the Bourke area saw deaths and ill-thrift in around a dozen goats out of 400 rangeland x goats in a 3,000 acre paddock. No abnormalities on post mortem, but evidence of regenerative anaemia in live goats and average WEC of 720 epg with 75% haemonchus suggests that internal parasites were an issue.
These two cases highlight the old saying that "common things occur commonly" and internal parasites should be on the top of the differential list as far as ill-thrift and deaths in managed goats are concerned.
There are only really three classes of anthelminthics registered for use in goats in NSW so strategic grazing management is essential when preventing overwhelming worm burdens in managed goats.
(Editor’s note: With regard goat drenches, consult your vet for off-label prescription of some other drenches.)
In the Coonabarabran region there have been very few worm tests performed in the last month, with those done showing average strongyle counts ranging from 160–800 eggs per gram (epg), with larval differentiation showing a mix of barber's pole worm (17–28%), black scour worm (24–58%) and brown stomach worm (12–59%). There was also evidence of nematodirus (thin necked intestinal worm) in 6-month old lambs, with egg counts from 0–351 epg.
With very hot, dry weather over the past 2 months, numbers of worm eggs on pasture should be decreasing. Producers should take advantage of this to prepare clean pastures. Spelling a pasture in this weather for 3 months will create a low-risk pasture, rather than 6 months required over winter. Producers need to remain vigilant, as a spell of wet weather could cause worm numbers to increase rapidly.
Counts for weaned lamb mobs have varied from 150 eggs per gram (epg) to over a 1000 epg.
Counts in dry mobs have varied from 0 epg to 80 epg. Production losses have been minimal, or none, in all weaned lamb mobs tested to date.
The rains that occurred from a few weeks ago seem to have stimulated a rise in infective larvae and have raised egg counts for producers that have tested their respective stock. Producers are reminded to be aware of the With Holding Period (WHP) and Export Slaughter Intervals (ESI) of drenches if they are planning on selling stock in the near future.
Producers who are having ongoing worm issues have been urged to clean up their paddocks as we move into the hotter summer months. An equally important reminder is to have a WormTest conducted in 4–6 weeks following their latest drench (which may or may not be necessary depending on climatic conditions during that period of time).
Producers who are experiencing production losses due to suspect worm burdens are urged to contact their local district veterinarian for suitable advice.
Blowfly preventative treatments are being implemented on a regular basis by producers as deemed necessary.
Across the Riverina, District Vets have been diagnosing cases of barber’s pole worm. Wagga Wagga and surrounds saw an unseasonably wet summer this year allowing barber’s pole to flourish. While so far this summer rainfall has been both limited and scattered, residual worms are proving to be a health issue. Clinical signs of haemonchosis include anaemia, oedema under the jaw, dullness and fatigue when moved.
We recommended WECs to determine whether worms are a current production and health limitation on farm. If drenching, repeat WECs 10 days post drenching to measure drench efficacy. Repeat WECs every 6 weeks, particularly over the current summer and autumn period. Note that if significant rainfall events occur WECs should be repeated sooner in some cases. Quarantine principles are highly important for any recently introduced sheep. A quarantine drench is recommended, this typically includes a drench with four active ingredients from different drug classes to ensure drench resistance is not introduced to your farm.
Generally, WECs have still been coming through the door. Now that harvest has predominantly wound up in our area, farmers will likely return to monitoring parasites more frequently.
Wishing everyone as Merry Christmas and a happy and safe 2016 from all the Vets at the Wagga Wagga Local Land Services.
I have just seen my first case of haemonchosis in about 3 years. This case documented death in dorper ewes with lambs at foot near Bingara. High stocking rates on a stubble paddock played some part in the causation. VHR laboratories have identified some high counts from the area, and conditions are right for an abundance of haemonchus over the summer, especially if storms continue. It has been hot for the past 4 weeks but storms are yielding good falls if you are underneath them. Predictions are for average rainfall over the rest of summer and therefore, more clinical cases to come.
Results from worm tests across the region:
Lightening Ridge—2 mobs tested, one property.
Walgett - 5 mobs tested two properties.
Burren Junction—1 mob
In the West we have had a few worm tests done this month on groups of 6-month old lambs. The average of the tests was 594 eggs per gram (epg) strongyle and 12 epg nematodirus. Speciation was done on these samples with the most prevalent type of worm being black scour worm making up 61% of the sample, then brown stomach worm making up 15–27% of the samples with relatively smaller numbers of large intestinal worm (11–13%) and barbers pole worm (1–11%). They also showed a low level of coccidia and an insignificant amount of tapeworm.
Some post-drench samples were also taken to look for any resistance to the drenches used. One group of weaners were drenched with a combination drench containing Abamectin, Albendazole, Closantel and Levamisole, which caused a complete kill of all the worms. The other group was treated with an Abamectin treatment and once again no worm eggs were detected after treatment.
(Editor’s note: drench resistance results are not regionally based, they will depend very much on you’re the drench history of your property and sheep [including where they came from]. Don’t assume a local result will apply on your property).
In the East there have been 2 cases of barber’s pole in spring lambs confirmed by post mortem. The cases followed a good rain event at the start of November. One case involved lambs that were about to be weaned and had not had any drenching. A drench resistance test on the lambs is being undertaken. The other case was in lambs that were drenched at weaning 4 weeks previously; therefore there is question mark on the effectiveness of the drench!
Results from worm egg counts performed in the East have been generally low, with no drenching required and only further monitoring depending upon summer rain.
Pastures have dried out markedly in recent weeks, putting pressure on worm larvae to survive.
Most producers have given a first summer drench without monitoring, knowing that worm counts are rarely low enough in breeding sheep around here to skip this important drench.
Recent worm egg counts show a significant proportion of Haemonchus remaining on about half our properties. While it is mostly too dry for Haemonchus eggs to hatch, summer storms can deliver substantial falls, such as the 45 mm that fell over a narrow strip to the south of us mid-December. And some paddocks have constantly green patches especially along flow lines that sheep will return to chasing a green pick, and which can become heavily contaminated with Haemonchus. So don't ignore the possibility of barber's pole worm trouble just because it's hot.
While it was only done in a small number of flocks, monitoring of worm egg counts 10 to 14 days after drenching recently showed you can't assume "triple combinations" will be effective in all flocks (see this month’s feature article). Some producers have used these products exclusively for several years, occasionally switching from one brand to another. Brown stomach worm was shown to be resistant to these convenient formulations on this occasion, demonstrating the value of a post-drenching worm egg count check. "Triple"-resistant Haemonchus are found regularly in other areas.
Hayed off pastures (which allowed any dags to dry) and hot weather also put a fairly abrupt end to any blowfly trouble for now. But remember to keep up the fly protection for rams' heads over the summer and autumn, to ensure they are right come joining time.
In the Yass region we have seen a rise in clinical cases of barber’s pole infestation with one farmer having losses across all classes of sheep. Producers are encouraged to check the drenches they are using whilst considering the known resistance to certain classes/actives. Conducting a post drench Worm Egg Count (WEC) is a good way to reassure yourselves of the effectiveness of the drench used.
In one lot of testing, results ranged from 360–7,640 eggs per gram (epg) with an average of 1604 epg (41% barber’s pole, 31% brown scour and 28% brown stomach worm).
There are reports of a few cases of illness or death from Haemonchus.
Many worm egg counts however are still relatively low. The outlook for Mudgee will mainly depend on rainfall.