NSW WormBoss Worm Control Programs
NSW WormBoss Drench Decision Guides
Wormtests in far western NSW have been few and far between in pastoral areas, and indicate minimal worm burdens. Far western NSW has had dry conditions to good cool season rains, usually slow and over a few days, so stock aren't facing patchy abundant feed that might lead to localised super-abundant larval loads. Stock are in good condition, allowing for variation in feed availability, which may be part of animals' ability to deal with any worms present. There have been some higher burdens found on a few small irrigated runs.
The predictions of a "Godzilla" El Nino and subsequent intense La Nina will be followed with keen interest. The generalised warming of oceans around the continent appears to me to have altered the usual patterns of systems and rains in central Australia, but that is an amateur meteorologist's opinion. More particularly, as part of other work, I've found marked increases in daily maxima and minima temperatures over the last 3 to 8 years, which may have some effect on larvae on pastures.
Comment from Dr Lewis Kahn: We had a modeler work with us some years ago and part of his work related ambient (Stevenson Screens) to ground temperatures (data loggers on ground). The key issues were that ground minimum temperature was lower than ambient minimum temperature while ground maximum temperatures were higher.
An explanation of the Stevenson Screen temperatures can be found on the BOM web site: http://www.bom.gov.au/climate/cdo/about/airtemp-measure.shtml
The changes in pasture cover in western NSW since the heavy summer rains over 2010 to 2012 may be playing some part in worm dynamics as well as risk of sheep exposure to infective larvae.
Only two WECs have come through this month. One, with an average of 340 epg (96% black scour worm), was part of a mortality investigation in some Merino weaners in the Coolabah district, which turned out to be positive for M.ovis (a protozoan parasite that occurs in the blood and can cause anaemia. It is transmitted by blood-sucking insects, such as mosquitoes, or other means that transfers blood between animals).
The other was a Worm Test a producer sent in from the Balranald area, due to scouring in ewes with lambs at foot, this had 760 epg and was 94% black scour worm.
The weather has warmed up in the west and with a bit of moisture around in parts, conditions are ideal for these worms.
Earlier this month DVs from Young and myself aided producers in our area to form a lice control group. Lice has been causing issues in our neck of the woods for the last few months, so producers from our area have banded together to address the problems (reminiscent of the old footrot groups). We provided technical advice on management procedures to be mindful of, and chemical classes and methods of application we would like to see used in order to better control the problem. As lice is no longer notifiable in the state our role is purely from an advisory perspective. This will be a 2 year program with producers voluntarily entering the program.
On the worm front, a few producers have submitted wormtests, and a few have had higher counts, but have had no clinical signs leading them to be distressed about losses in production. Appropriate drenching with relevant advice provided by their local district vet has helped alleviate some of these burdens.
An interesting case did arise a few weeks back with a 12 month old wether mob that had been on the back foot ever since they hit the ground, and which was further compounded with stock losses of up to 7% in this mob due to what is now being put down to as a worm burden (possibly due to a chronic disease state? The jury is still out on this one). Strongyle counts were as high as 2200 epg for the mob with whipworm and coccidia also being present in high numbers. Drenching seems to have alleviated the problems for now, but the paddocks they were in are now heavily contaminated, but the good news is that both paddocks are due to be ripped up and stock aren't going to put on there for several years as a result.
Spring is approaching. The producers in our area and beyond have been reminded of the need to monitor stock for signs of increasing worm burdens, especially as weaned stock go on to new paddocks.
From a subjective assessment driving around the Wagga Board region and consulting with producers, there has been an obvious increase in the number of scouring sheep over the last month. Most producers that I have consulted with have been attributing this to ‘nutritional scours’ due to the current pasture moisture content and although a majority of cases probably are ‘nutritional’, visual assessment is never as accurate as a worm test [as I have heard NSW DPI Veterinary Parasitologist, Stephen Love say many times “never assume anything!”] Furthermore, we need to be mindful that this scouring could enable or advance underlying gut pathogens (such as a minor worm burden, coccidia and various bacteria). This is particularly true if the animals are also enduring harsh weather conditions at the time.
Few worm egg counts have been conducted in the last 2 months, however, from reports received, black scour worms with moderate egg counts (50–100 epg) have been the predominant species identified, which is tolerable. I expect to see an increase in the number of WEC over the next few months, particularly as the weather starts to heat up.
With good rains and green paddocks scours in sheep have been on the rise. While it is often feed related, at this time of the year when the grass is green, it can also be worm related. Scours at any time of the year is the most obvious sign suggestive of a worm infection in the mob.
The best thing to do is to carry out a worm egg count with culture to determine the type of worms. Knowing the types of worms is important, especially in winter. This gives the advantage of knowing if summer worms such as Haemonchus (barber’s pole worm) are going to be a problem later in the year. This will help with drench decisions now and come summer. Just drenching without knowing the amount of worm eggs and the type of worms can increase the costs of productivity.
Worm egg testing is invaluable to your drench decisions. In the Pastoral area around Hay we have had a high count of worm eggs in a sick ewe (4200 strongyles eggs per gram) and some sick lambs (920-640 strongyles eggs per gram). Recommendations are for immediate worm egg counts with culture and then follow the drench decision guide found at WORMBOSS.com.au.
In general, frosts and dry conditions through August have dominated most of the areas in the northern tablelands. This means Haemonchus will not get an early start to the spring season. Western parts of the northern tablelands have experienced milder conditions and Haemonchus counts are on the rise.
In addition, as Rad Nielsen from VHR has previously stated, producers still need to be vigilant when it comes to the presence of scour worms, particularly Trichostrongylus (black scour worm).
Producers should be deciding in the next few weeks which paddocks they will use for weaners. Typically these prepared weaner paddocks should be spelled from sheep grazing in October, November and December for a January weaning.
Around Warialda and Bingara the season since December 2014 has been excellent for worms apart from some patches of really cold weather. Despite this we have seen only moderate worm burdens in some counts done around the area and there have not been any clinical cases. I suspect the winter has kept things at bay along with the previous 2 years of drought.
This coming spring and summer will be a test for sheep producers if the good season continues.
Black scour and brown stomach worms have quickly risen to prominence in lambing ewes and in weaners across the district. Under-nutrition plays a role in all cases investigated so far.
In one case, merino weaners grazing short, green, but previously heavily frosted native pasture began to die suddenly, with little scouring. These lambs had grazed the same paddock all year, with regular short acting drenches and some monitoring. They were pretty well grown, but had eventually succumbed to what appeared to be mass hatching of mainly black scour worms.
Another case involved purchased adult merino ewes lambing on mainly native pasture with some supplementary feed provided. These ewes had been given a drench plus vaccine injection in April, and a couple of liver fluke drenches since. These ewes were weak and had "bottle jaw", which suggested they might still have liver fluke. However, the loss of protein was due to brown stomach worms together with some black scour worms.
A third case involved merino ewes lambing on exceptional pasture, mainly clover. These ewes were in poor body condition, the result of worms and malnutrition in autumn. The owner had done a magnificent job on providing good feed for these ewes to lamb on, but forgot to check their worm levels prior to entering these paddocks. Despite the good feed now available to them, these ewes were unable to reverse the earlier weight loss, due to a massive burden of black scour and brown stomach worms.
The same worms rapidly re-infested merino weaners following a drench just five weeks previously, causing scouring and deaths. These twelve-month old lambs went onto a not-so-good paddock for a fortnight after drenching. A big mob of adult rams also rapidly became re-infested with black scour and brown stomach worms when run on short native pasture after drenching. And another mob of young ewes picked up worms when grazed for just a week on heavily contaminated sheltered paddocks after shearing and drenching.
The main observation is that sheep have picked up fatal worm burdens in a very short time, often within weeks of a drench. Don't be lulled into thinking it can't be worms, just because you've not long drenched.
Some sheep are also carrying a fair proportion of barber's pole worms at present, but with no evidence of disease. It will soon be warm enough for the worm eggs from these barber's pole worms to hatch, so now would be a good time to deal with them.
No clinical cases of worms have been examined in the region this month by district vets.
Of the few worm tests being done we are generally finding very low levels of eggs, ranging from 0 to around 20–40 epg for strongyle and around 20 for Nematodirus. In the east, one of the worm egg counts was 77% barber's pole worm.
A few properties have shown a little higher counts; 200–250 epg strongyles, which have been largely black scour worm.
Very low levels of tapeworm were found on one farm and low levels of coccidia have been fairly consistent and widespread across the region.