NSW WormBoss Worm Control Programs
NSW WormBoss Drench Decision Guides
Again this month sheep worm counts in the Coonamble area remain low due to the ongoing dry conditions.
It is anticipated that when the cold weather kicks in, cattle lice will become an issue. Producers who routinely treat on the first frost for lice are urged to consider that some lice products will treat worms as well. So choose something that is effective, use the correct dose for the body weight, and apply it correctly to get the best internal and external parasite control result. An internal parasite treatment will really help nutritionally stressed cattle under the current seasonal conditions.
It has been very quiet on the worm side of things for sheep at the moment.
I did see moderately high worm burdens in young calves that had missed their weaning drench. So a reminder - just because it's dry, it doesn't necessarily mean that calves are not wormy.
Dry conditions are continuing, and most worm egg counts that have been conducted are reflecting this. However, undrenched young sheep or pre-lambing ewes may have worm burdens that could be affecting production. Sheep producers are advised to use Worm Tests to determine whether a drench is required.
In the north-eastern part of the Riverina Local Land Services district (e.g. the West Wyalong—Young—Harden area), autumn lambing is underway on many properties. These mobs will need to be monitored prior to lamb marking to determine if any worm burdens have crept up during the lambing period. A bit of forward planning by producers to collect faecal samples from ewes for a worm egg count at least 10 days before bringing the mob in for lamb marking will go a long way to determining if the ewes need a drench at that time. Lambs generally don't require drenching through the cradle and can wait until weaning time.
Counts in mobs around the area have varied from farm to farm, and also with each property's drench history, so each farm really needs to do an assessment of their own stock. A WormTest is a simple process of collecting 10 fresh poo samples from the mob and submitting them to either your local reseller if they provide the service, or to the NSW State Veterinary Diagnostic Laboratory. The best place to find fresh samples is from the sheep camp early in the morning, or you can muster the mob into a corner of the paddock and just let them stand there for a few minutes. This is usually enough to make them nervous and happily supply the samples you need! Then you let them move off and go and collect the 'treasure'.
Your Local Land Services office typically carries worm testing kits from the State Veterinary Diagnostic Laboratory that can be posted as a complete package. Give them a call or drop in and see them. They can then assist you with the interpretation and advice, once the results are in.
Many producers in the Wagga Wagga area have finished pregnancy-scanning ewes and are preparing for lambing. The peri-parturient period (the few weeks before and after an animal births) presents the highest level of metabolic stress the animal is likely to experience in its entire life. As most producers will know, the energy and mineral demands associated with the final stages of foetal development, the physical process of birthing, and then lactation, are compounded by a reduced feed-intake capacity. Generally, maiden ewe mobs are more susceptible, however, older ewes will also suffer if not well managed.
This considered, farmers need to ensure internal parasites are one less thing stressing ewes at this dangerous period in their life. In my opinion, strategic pre-lambing worm egg counts are critical. Many producers will blindly administer a pre-lambing drench without any knowledge of the worm burden they are treating or whether the drench will actually be effective. This is an expensive and inaccurate method of drench management on-farm. I encourage sheep producers to test their ewes pre-lambing (via WormTest), to determine the importance of a drench treatment. Technical support through the process of collection, submission and interpretation of results is available—call your local District Veterinarian.
Around Wagga recently, we have been seeing moderate worm egg count results in pregnant ewes, indicating a pre-lambing drench in necessary in those mobs tested. In the event of a poor response to drenching a pre-drench worm egg count result becomes invaluable as it can help to identify drench resistance. If you suspect you have drench resistance seek professional technical advice— again, your local District Veterinarian is there to help.
Even with dry conditions prevailing, a number of producers around the central Riverina area have returned moderate worm egg count (WEC) results from both sheep and cattle over the previous month. A herd of cows with calves at foot returned a WEC of 200 strongyle type eggs per gram (epg) of faeces. This burden was likely predominately brown stomach worm (Ostertagia ostertagi). A mob of Merino ewes with lambs at foot returned a WEC of 400 strongyle epg and 40 nematodirus (thin necked intestinal worm) epg. Strongyle eggs in this case were also likely to be brown stomach worm (Teladorsagia circumcincta) and/or black scour worm (Trichostrongylus spp.).
Producers are urged not to forget barber's pole worm (Haemonchus contortus) at this time of year. A barber's pole infestation in Dorper ewes with lambs at foot was found on post mortem during a sudden death investigation.
It is recommended to feed supplementary feed off the ground, thereby limiting the intake of worm larvae. This will be especially important if we get some autumn rain—as feeding sheep and cattle off wet ground presents a number of problems, not just increasing worm burdens.
Conditions are remaining very dry and not many worm counts have been conducted. I suspect there are a lot of underweight weaner sheep in the district.
All the cattle at our weaner sale today went north.
Liver fluke: My comment would be to suggest people hold off on the autumn fluke drench a little longer until it gets cold enough to break the fluke cycle.
No official worm egg count results have come through in our district. I think sheep numbers are declining, and the dry weather has brought a sense of worm security. I had one clinical case of haemonchosis (barber’s pole worm disease), but it was at the local school so it was not exactly normal pasture conditions. The grass was short, a little overstocked, and also set-stocked to some degree.
(Editor’s note: No doubt a good first-hand lesson for the students about barber’s pole worm!)
In the Eastern region due to the continuing dry season there have only been a few worm egg counts undertaken. Two properties were diagnosed with Haemonchus contortus (barber’s pole worm). One property had drenched prior to the good rainfall in early December and now has high levels of haemonchus throughout the flock. A program has been implemented.
Properties that have a known liver fluke issue should consider an appropriate treatment. April/May drenching will eliminate any fluke that has been picked up during summer and early autumn. If you are not sure if liver fluke is on your property, contact your local veterinarian or district veterinarian to discuss the situation.
Only two worm test results were submitted from the Western part of the region in the last month. The first result was from a mob of dorper lambs that had been drenched with a moxidectin drench in February. These lambs had a faecal egg count of 0 eggs per gram (epg). The other result was from a mob that was last treated with an ivermectin drench in October last year. This mob had an average faecal egg count of 60 epg strongyle type. Both samples contained low amounts of coccidia.
A recent investigation on a mob of scouring sheep showed a worm egg count of 0 epg. While the diagnosis could not be confirmed, coccidia could not be ruled out as a cause of the scour, and the problem seemed to stop after the sheep were moved to a new paddock. A large tapeworm was also incidentally found at the time of post mortem, but was no cause for concern.
A number of WormTests have been received across the region during April. Results have been highly variable, with average eggs per gram ranging anywhere from 40 to in excess of 2500. Where a larval culture has been carried out, barber’s pole worm has been the dominant species.
With drought now upon the region, how is it that the dreaded barber’s pole worm has seemingly been able to keep ticking over on some properties? It is likely a reflection of larvae developing during the very few short heavy rain periods (mid and late January and late February around Braidwood) and that in many parts of the region we didn’t get high enough daily maximum temperatures to kill a large percentage of larvae. It may also be that stock are grazing closer to the ground due to lack of feed availability and are therefore picking up more larvae with every mouthful. However, in some parts of the region it may be because the barber’s pole lifecycle has managed to continue this autumn, even in the face of the current dry season. How can this be you might ask given we have had very little rain? Well remember, very little rain is enough for the barber’s pole – it only takes 10-15 mm of rain over a few days with temperatures over 18°C for these eggs to hatch into larvae. Given that females are prolific egg layers, laying up to 10,000 eggs per day, even a single rainfall event can lead to significant pasture contamination with newly-hatched barber’s pole larvae.
But why only on some properties and some mobs? Just luck that those mobs were carrying a heavy enough burden of barber’s pole when rain fell and conditions favoured those eggs laid in the last few days to hatch to larvae, and that those affected paddocks were then grazed at the right time for sheep to pick up this burden.
Next question—would you be prepared to not drench a mob of ewes with an egg count in the 500–1000 epg range with close to 100% of these eggs being from barber’s pole? Maybe this year you should be. On the one hand sheep could be picking up barber’s pole larvae already on pasture. However, further pasture contamination is of little concern because any barber’s pole eggs passed by sheep are now doomed – temperatures are still over 18°C but in the vast majority of the region there hasn’t been enough rainfall at any point during the last month to lead eggs to develop into larvae. If you’re going to wait keep a close watch on sheep, including with monthly worm egg counts and cultures (or a little sooner if counts are nearing 1000 epg). Be prepared to respond if counts rise rapidly or if we get some much needed rain while daytime temperatures continue to exceed 18°C. You will need to remove these barber’s pole prior to spring, before warmth and rain again leads to the hatching of eggs. For some of these mobs this will coincide with a drench pre-lambing or at lamb marking.
Don’t forget that WormTests from a single mob do not necessarily reflect the worm burden in different mobs on the same property. As an example, one farm submitted samples from multiple mobs with average worm egg counts ranging from 100 to 2620 epg. Avoiding drenching mobs with low worm egg counts can save you heaps of money and help you to avoid future issues with drench resistance (refer to my contribution from July 2017 on the cost savings delivered by WormTests).
A final note on liver fluke—remember that after the first frosts is the time to drench mobs that have grazed fluke-prone paddocks over summer. For most parts of the region, conditions last spring would have been sufficient to keep the lifecycle going so don’t assume that you can get away with skipping a liver fluke drench this autumn because things have turned dry. Ensure the drench you use at this time of year is effective against all stages of fluke (i.e. it must contain triclabendazole). And don’t forget about alpacas, which are particularly susceptible to the clinical consequences of liver fluke infection.
It is incredibly dry. Producers are offloading and/or hand feeding stock. Not only is it dry, but we are still experiencing very high temperatures, with daily temperatures this week expected to be up to 38 degrees centigrade—this will shorten the life of any worm larvae that have survived so far. Thankfully it has been a little cooler through the nights.
There was only one WormTest submitted in March/April. It was for a mob of 500 managed goats. The worm egg count was negligible.
Some producers have commenced, or are considering, lot feeding. They have been advised to keep feed off the ground where possible, and monitor for worms. An induction drench and vaccination is common practice on entry to the lot.