NSW WormBoss Worm Control Programs
NSW WormBoss Drench Decision Guides
You are invited to the WormBoss Workshop, Thursday 14 June, near Guyra.
June in the New England has been remarkable because we have had way more than average rain for the month! This is noteworthy because this is our fourth year in a row with below average rain. The only other month recently in which we scored much more than average, was January, and that had flow on effects, mainly with barber's pole worm into February and March, even though we went back to the all too familiar dry pattern in late summer and autumn.
So, there is a lesson here: if viable worm eggs on pasture 'hit a purple patch', i.e. it is warm enough and wet enough for egg development and hatching, then the resulting larvae, generally much more resilient than the eggs, can survive for weeks and even months come hell or high water. OK, maybe that's an exaggeration, but below average rainfall, or cool to cold conditions, don't bother infective (3rd stage) larvae too much. What really cuts their life short is very hot days, e.g. 35 degrees plus, which we don't seem to be experiencing lately.
Problem 1: eggs are only viable on pasture for 5 days or so.
Problem 2: eggs are delicate little princesses and need plenty of warmth and moisture in order to produce larvae (night and daytime temperatures over 10°C and 18°C respectively, and 10 mm of rain or more every several days).
Solution: fecundity! Adult female worms pump out bucket loads of eggs so that when conditions are right, there are plenty of viable eggs ready to go.
This is helped if sheep are set-stocked rather than rotationally grazed, the latter involving spelling of pastures, alternate grazing with cattle and perhaps cropping as well.
The end result of good grazing management: fewer paddocks carrying bucket loads of viable barber’s pole worm eggs.
So, what does this mean for now? Well, although it’s too cold for barber’s pole to complete its cycle, larvae produced in autumn will survive through to spring, albeit in decreasing numbers. So, sheep can still get infected with barber’s pole in winter. And indeed, we are seeing this. The occasional mob in this region is still scoring high worm egg counts (WECs), usually mostly barber’s pole. The biggest count I saw recently was from Gundagai—OK, not the New England—but the average WEC was 11,000 eggs per gram (epg) and one sheep had a count of 20,000 epg.
I am guessing the Gundagai farm has a drench resistance problem as well, but they are in good company as almost all producers do, and maybe 90% of producers don't have a good handle on what drenches work on their farm. The answer: at the very least, do regular DrenchChecks. It's easy-peasy and as cheap as chips, especially if you factor in the bucket loads of extra money you will make by using effective drenches.
Other worms in winter? Well, the scour worms produce eggs that are more cold- and desiccation-tolerant than barber’s pole. Even so, the dead of winter is too much in most areas for black scour worm eggs, but the eggs of brown stomach worm might still manage to produce larvae except in the much colder areas. And worm problems in winter can be made worse by sheep being nutritionally 'stretched'.
Bottom line: expect that your sheep will be picking up new worm infections over winter—and that includes liver fluke as well—especially if your grazing management wasn't so good in the autumn months, and more so if you are unwittingly using ineffective drenches as well.
The answer: keep up regular WormTests, even in winter. This is all too much information? Here is another answer: 'Your Program' is one of your best friends. Unlike faux friends, it's always there and ready and able to help. 'Your Program' is on WormBoss and it's printer friendly, well laid out, easy to follow and practical. ‘You can't do better."
Very wet in the Bourke region with 53 mm of rain falling over the last 5 days and more is predicted. Low numbers of scour worms were identified in a WormTest from a mob of weaner merino sheep. Drenching was not warranted.
The Coonamble district has experienced 100 mm+ of rain in the last ten days after a prolonged dry period, and temperatures remain unseasonably warm. There have been very few WormTests submitted from the Coonamble region lately, so gauging worm burdens accurately is difficult. Those that have been done in sheep show mainly low burdens of Trichostrongylus spp. and Teladorsagia (Ostertagia) spp.
Buffalo fly are still present in cattle herds around the Quambone district.
The Nyngan area has seen 150 mm+ rainfall over the last month. Only a few worm egg counts have been performed by EMAI, local Ag stores, LLS, and private veterinarians. While worm egg counts have been low, it is difficult to gauge general worm burdens based on only a few tests.
Once paddocks become more accessible and lamb marking begins, producers should consider taking faecal samples for worm testing to get an idea of the worm levels in their sheep. Luckily for producers in this area, drenching has generally not been required so far this year. However, it is important to remain vigilant in identifying when worm numbers start to increase and repeated WormTests are the most practical and cost effective method.
Worm egg counts this past month have been moderate to low (average of approx. 150–200 egg per gram) and larval differentiation results showed primarily Trichostrongylus species (a larval culture needs to be requested with the WormTest).
Average temperatures for this month have ranged from 6°C (night time) to 14°C (day time), and will aid in keeping counts low. Producers are reminded to conduct worm egg counts leading up to lambing, and to monitor mobs for signs of increasing worm burdens.
As part of the lice control group in Young, a few properties have been inspected for lice and interest in the group is gaining momentum in other Riverina LLS regions. Lice is not a notifiable disease in NSW. This group was formed by producers; LLS officers act only as intermediaries to help the group by providing property inspections, bi-yearly meetings and updates, and providing maps and other pertinent information to better control and eradicate lice. The group is trialling a two-year program with the possibility of extending the program by a further year or two depending on interest at that time.
In the western part of the region, only one WormTest was submitted from some poor-doing ewe hoggets. There were no strongyle or nematodirus-type worm eggs, only very low numbers of coccidia present in the sample.
There weren’t any reports of clinical issues due to worms in the last month.
In the eastern part of the region, a property undertaking pre-lambing drenching based on worm testing, received a WormTest result of 960 eggs per gram (average) in 2-year old ewes, with the larval culture indicating a haemonchus infection. On another property, haemonchus infection was diagnosed by post mortem in 12-week old lambs. This producer had lost 20 lambs in the previous week. The property has ongoing haemonchus problems and the grazing management and drenching programs will be reviewed to reduce the impacts of haemonchosis on the property.
Overall, worm egg counts have been what you would expect at this time of year in the Eastern MLLS.
Widespread rainfall across the district and mostly mild temperatures helped improve feed quality for sheep, though quantity lags well behind demand on most properties. With it, the numbers of black scour and brown stomach worms have increased, but remain at pretty low levels. Worm egg count monitoring indicates that some flocks will not require a pre-lamb drench. Any high worm egg counts will still be due to barber's pole worms originating from autumn-hatched larvae. While it is now too cold for barber's pole worm eggs to hatch, grazing history through autumn affects selection of lambing paddocks, as those autumn-hatched larvae will survive through winter.
Be alert to the possibility of liver fluke returning. Fluke apparently disappeared from many properties during the last drought, as springs, creeks and swamps dried out. Tests recently conducted have shown liver fluke returning to some properties, despite the use of drenches effective against both fluke and barber's pole worms. Positive blood tests on sheep or cattle provide an early warning of liver fluke. Signs of fluke burdens look similar to barber's pole, with anaemia, weakness and occasionally bottle jaw. One owner reported his crossbred ewes with lambs at foot, and grazing an oat crop, were not "doing as well" as they should have been; a fluke test on dung samples showed high numbers of fluke eggs. Deaths from black disease occurred in one flock recently, due to damage from immature fluke. Black disease is one of the "six-in-one" clostridial diseases prevented by routine vaccination. Deaths occurred in yet another flock following a fluke drench, when a mass of dead fluke "clogged" the liver causing liver failure.
It is a good time to be looking for lice on spring-shorn sheep. Lice can be hard to find when wool is very short, but tell-tale chewed and rubbed patches will be showing up now in sheep with more than six months' wool growth. You may not need to treat for those lice just yet, but plan your approach to lice control next shearing. We mostly blame our neighbour when our sheep are lousy, but if lice are widespread in your flock six months after treatment at the last shearing, it is more likely that the shearing treatment failed. It is important to work out why, to avoid a costly repeat failure.
Prolonged periods of wet weather have been very welcome but could be a factor leading to an increase in winter worm issues.
Most producers around Mudgee are all too familiar with barber's pole, but may not routinely see the effects of black scour or brown stomach worm over winter. It's important to remember that because these worms lay fewer eggs than do the prodigious barber's pole, lower egg counts should be used when deciding to drench.
Another important consideration is a pre-lambing drench for ewes, which should be given about a month before lambing. Ewes should also be moved to low-risk worm paddocks prior to lambing.