Worm egg count results from the New England region over the last month continue to remain in the low to moderate range in the majority of cases, however, some properties have recorded high mean counts (in excess of 1000 epg). This fact highlights the variation that typically occurs between different management systems and the need for regular worm monitoring at all times of the year.
Over the last month we have been receiving submissions from clients checking the worm status of ewes prior to lambing. A great proportion of these mobs have counts in the moderate range (200–600 epg), justifying the need for a pre-lambing drench. Interestingly, a few stood out for being quite low, despite the fact that the sheep had not been drenched for a lengthy period. These included Merino ewes in the Walcha district that had mean WECs (worm egg counts) of 28 and 76 epg (last drench given 6 months earlier) and XB ewes in the Guyra district with a mean WEC of 76 epg (last treated 4 months ago). In both these cases some form of planned grazing management is applied, incorporating rotational grazing and co-grazing with cattle. It is pleasing to see sheep producers clearly benefiting from applying such strategies. Neither property will be administering a pre-lambing drench to these sheep and the worm challenge over the lambing period will continue to remain low.
VHR (in partnership with Merial Australia) have recently released a new worm identification test, which enables faster and more accurate identification of sheep roundworms. Unlike conventional larval differentiation testing methods, the E-DNA Worm Test detects which species of worms are present in a worm burden by looking at their DNA. Combined with a normal worm egg count, the E-DNA Worm Test can detect all the major sheep roundworms. Identifying the worm species and numbers present in a mob is essential for making optimal decisions about when animals should be treated (if at all), and allows producers to design control programs, and use products, that will target the particular parasites that are present. E-DNA Worm Test Kits are available to graziers across Australia through leading rural resellers.
Need to check your drenches and get with ‘The Program’
Eye-balling the sheep WormTest results from two of the major labs in NSW (VHR and EMAI), I see there are some relatively high worm egg counts in various locales, even in areas such as north eastern NSW and southern Queensland, which have had record or near record low rainfall for the last 12 months.
So, why the high counts (e.g. >2000) in some flocks, including those in drought-affected areas?
Of course there are a number of reasons, but a common one is the unwitting use of drenches rendered ineffective by resistant worms.
Although testing drench effectiveness is cheap and easy (see info on DrenchCheck) farmers like everyone else are afflicted by busy-ness: driven by the tyranny of the urgent rather than guided by the truly important.
Still, simple things like using drenches known to be effective through on-farm testing reap huge rewards.
Another way to make great gains is to get familiar with and follow Your Program in WormBoss. It’s very easy to read, and not too hard to apply. But, like all important things, it does take some time.
Wormtest results have been sparse this past month, and of the few properties results were received from, counts were usually lower than 200 epg.
Several producers have reported scouring in their mobs, but this was likely due to the pastures being in a highly digestible state with a reasonably high water content present as well. This is a common finding around the district.
There was, however, 2 properties showing high percentages of barbers pole with an average of 96% reported on larval differentiation (av. egg count of 450–500 epg, with counts of some individual animals exceeding 1000 epg).
One property has experienced mortalities in lactating ewes, seeing roughly 30 ewes affected. This was attributed to barber’s pole worm and immediate drenching of the affected mob has stopped further losses.
Producers throughout the district have been told to be mindful as we approach springtime and to get wormtests done over the next few weeks to ensure they do not go through any issues moving forward.
Moderate to very high egg counts have been seen in sheep in the western area of the Riverina. In adult lambing ewes, counts of up to 5800 epg (predominantly Trichs and Ostertagia) were seen in clinically affected sheep. The marginal season in the western part of the Area seems to be precipitating heavier burdens than normal on some properties where routine drenching, particularly of adult sheep, is not always conducted. Producers are advised to Wormtest if in doubt and to seek veterinary advice regarding treatment.
It has been good to see a number of worm tests being done recently. As is often the case, there has been a lot of variation in results in Wagga Wagga, both between farms and between mobs on the same farm. There have been some high counts in ewes and weaned lambs, mostly consisting of scour worms. It seems pasture contamination with scour worm larvae is still significant in many places.
There were a couple of notable worm cases in our region this month. One was a case of young lambs at foot with significant worm burdens causing scours and illthrift, which is an unusual finding prior to weaning. Another was a worm test which came back with spectacular counts ranging from 4,000-18,000 epg in weaned lambs that had not been given a weaning drench. Unfortunately, worm species identification was not done, but moderate losses of lambs with anaemia symptoms suggested a diagnosis of barber's pole worm.
Lame sheep and lambing issues like prolapse have overtaken worms as our number one sheep health topic. A few owners had to scramble to give a pre-lambing drench, when worm egg counts climbed to danger levels in the weeks before lambing. Several other owners were reluctantly convinced to not give a long-acting pre-lamb worm treatment (capsule or injection) to their ewes this year, because worm egg counts and paddock contamination were at very low levels. They waited anxiously for results of follow-up worm egg counts prior to lamb marking, and have been pleasantly surprised at both the continuing low worm egg counts and the good condition of both ewes and lambs—proof that there are ways other than drenching to help control worms in sheep.
A few shitty, slab-sided hoggets have turned up on most places in the past couple of weeks. Worm egg counts on these mobs have pretty low averages, so it is easy to blame "capeweed" for the dags. Scour worm eggs are starting to hatch in big numbers, and these scouring hoggets are often those that over-react to the resulting worm larvae. There's little value in drenching the whole mob, but drafting off and treating this tail is worthwhile. The same sheep repeatedly get dags, so it is good for morale to keep them in a mob on their own, rather than leave them to spoil your view of the bigger mob each time you do your rounds.
Blame it on kangaroo damage or the popularity of sheep breeds that don't respect boundary fences if you like, but a surprising number of flocks have sheep lice for the first time in years. It is often detected in only a couple of sheep, or just one mob. With our spring shearing run about to kick in, now is a good time to detect that odd sheep with sheep lice, with the aim to eradicate at or immediately after shearing.
Some worm monitoring has occurred this month in hoggets and wethers. Larval cultures and the E-DNA worm test have been valuable during the winter to demonstrate that many of the high counts in individual sheep are due to Haemonchus. These increasing counts have shown continual larval pick up of Haemonchus though the winter in mobs that are grazing pastures contaminated with eggs in the autumn.
Of greatest concern to those producers is the management of Haemonchus this spring while concurrently managing scour worms. Some have identified a developing resistance problem in Haemonchus to moxidectin. Many producers will be using closantel early this spring as temperatures warm to stay ahead of a Haemonchus outbreak, and then rotating to a drench that they know to be fully effective against scour worms and Haemonchus for the first summer drench.
Nutrition of the animal strongly influences the magnitude to which parasitism develops and parasitism reduces production. The excellent nutrition and pasture height available this winter combined with effective summer drenches has seen very low worm numbers in many monitored wether mobs this winter.
The cold dry weather has dampened the worm activity somewhat. However the recent rain around Braidwood and Bungendore should stimulate parasite uptake next month. At least 10 young liver flukes were found in a hogget from a property south of Queanbeyan. These were most likely picked up in the rain period of May/June.
There have been no worm tests submitted in July. Conditions continue to be very dry in the Bourke district. One sheep flock was investigated due to ill-thrift, which has been attributed to both a lack of suitable nutrition combined with pregnancy and a considerable worm burden of Haemonchus and Trichostrongylus, which was almost certainly imported with the sheep, which were purchased from the Coolah district in February this year.