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New South Wales worm update - March 2014

Rad Nielsen, Veterinary Health Research, Armidale (rnielsen@vhr.com.au)

Severe drought conditions have been unfavourable for larval development and survival across the north of the state. Worm egg counts have typically been lower than in “normal” summers and many graziers have been able to significantly decrease their drench use as a result. Western area producers in particular have been able to leave sheep undrenched over the last 3-6 months. There are always exceptions to the rule, however. A recent worm kit had a mean worm egg count in excess of 5,000 epg, indicating high levels of pasture contamination (and possibly prior use of ineffective drenches). This highlights the importance of worm monitoring in order to establish the worm status of individual mobs.

Rain in some areas since mid-March has been sufficient to initiate larval development. Graziers need to be mindful of the potential for rapid rate of infection in sheep, particularly when set-stocked with low pasture availability.

Liver fluke infections in both sheep and cattle are more prevalent in the New England region this summer. Stock have been forced to graze in the normally wet areas of paddocks, ingesting liver fluke in the process. Treatment for this parasite is advised over April/May (if not already given) on those properties with known positive fluke status. If uncertain or seeking confirmation, fluke egg counts on faeces or blood antibody analysis are the common laboratory tests utilised to establish liver fluke status of livestock.

LOCAL LAND SERVICES DISTRICT REPORTS

Riverina LLS

Colin Peake, Hay; (Colin.Peake@lls.nsw.gov.au)

After some showers of rain over the last few weeks around the Western Riverina, some over 50mm, there is a green pick coming through. Hungry sheep are chasing the green pick, which, obviously is close to the ground and centred where water collected. More wormtests are coming in and some have been high with strongyle (brown stomach worm & black scour worm) counts in the thousands, which is not that usual out here. Post drench tests that have been done have been very good with one case of 0epg after a drench when the pre-drench test was over 2,000epg. 

It shows that even out in the Western Riverina pastoral areas, worms can be a problem, especially where sheep, in high numbers, graze close to the ground chasing a green pick, after a dry period, in a small area can be exposed to a worm egg burden as well. Especially as these sheep will be in lighter condition after a dry period. 

It would be wise to worm test your sheep now, especially if you have been under some of these falls. Also a lot of producers are due to start lambing over the next 2 months, so a pre-lambing wormtest and drench if required fits in very well at the present time.

Wagga Wagga office:  DVs Amy Shergold (amy.shergold@lls.nsw.gov.au) and Tony Morton (tony.morton@lls.nsw.gov.au)

Worm egg count monitoring has really slowed this month. Monitoring for barber’s pole worm was done on some weaner lambs because they were anaemic; however worm counts were negligible and consequently barber’s pole was not found to be the cause. Another property in Tarcutta had highly variable counts on routine monitoring with most high counts relating to barber’s pole. It is worth keeping barber’s pole in mind, particularly after rain. Monitoring should be scheduled 4-6 weeks after significant rain (let’s hope). Other monitoring has revealed relatively low burdens of scour worms.

One producer in our area is currently preparing weaning paddocks using the ‘Smart Grazing’ program. He has already grazed the weaning paddocks for 4 weeks at a high stocking rate using wethers and ewes that had just received a first summer drench. The paddocks were then spelled. He is now up to his second round of grazing in which the same sheep are put back on the pastures after a second summer drench. The purpose of this is to minimise pasture contamination using ‘clean’ sheep to mop up the larvae and reduce the dry matter, which makes it harder for larvae to survive.

Worm tests were run on weaner cattle on a couple of farms. Although more difficult to interpret than sheep egg counts, one farm had several animals with counts >150 epg, which indicates they need a weaning drench. Larval culture revealed a mixed burden, consisting mostly of the small intestinal worm (Cooperia) with a small percentage of the small brown stomach worm (Teladorsagia). This distribution is typical for cattle in southern regions. 

Young office:  DVs Rahul Shankar (rahul.shankar@lls.nsw.gov.au) and Eliz Braddon (eliz.braddon@lls.nsw.gov.au)

March has been a fairly quiet month on the worm front.

Most mobs being tested are from pregnant ewes due to lamb in April or May or from producers checking some of their mobs after their second summer drench. Results have ranged from 0-200 epg on average between the various mobs, the vast majority of those being well under 200epg.

Compared to March 2012 and 2013 there are no cases of Haemonchus in tests that were conducted for the past month. However, with recent rainfall ranging from 8-21mm and the start of the autumn rainfall around the corner it would be good to monitor worm egg counts and larval differentiation patterns paying particularly close attention to Barber’s pole worm. High levels of mectin’ resistance in local haemonchus populations have been reported in our drench profiles, and as mentioned in a previous report, drench choice is very important here.

As a reminder ewes should be vaccinated (either a 5 in 1 or 6 in 1), 2-6 weeks prior to lambing to prevent diseases such as pulpy kidney from occurring down the track.

Alexandra Stephens [alexandra.stephens@lls.nsw.gov.au]

On properties in the Yass region many worm counts were conducted during March looking for the cause of ill-thrift and anaemia in weaners. Generally we found that if sheep had been drenched in December or January they had not picked up worms over the dry summer and parasitism was not the cause of the ill-thrift.  Some producers were caught however by doing a single bulk worm egg count on the weaners, rather than 10 individual tests.  Some individuals had a much higher worm count (780 epg) than the average worm count in the mob (20 epg).  It was thought that the tail ender weaners were not feeding as well on the supplementary feed and thus protein and energy deficiencies lowered their immunity to parasites more than the general mob.  Many properties who had given the first summer drench when the pastured had dried off in late December found that they did not need to give a second summer drench, with worm counts averaging from 0 to 40epg. On the other hand we found that some mobs that had been drenched back in November had very high worm counts and yet were not scouring or showing obvious signs of worms because of the dry feed diet.  We found that on the properties that returned higher worm counts a larval differentiation was very necessary in drench selection.  Both to identify a carry over Barbers pole population, and to select the best drench for the worm population given previous drench test results showing a large variation in drench resistance between the worm types. 

We have not seen any evidence of fluke so far, but have definitely been testing and looking for it in those mobs concentrating their grazing onto the creek edges.

South East LLS

Petrea Wait, Cooma (petrea.wait@lls.nsw.gov.au)

While the producers on the Monaro have welcomed the change to cooler conditions and some reasonable rains, so have the worms. Some areas have received up to 5 inches of rainfall and we have even had an early light frost.

Worm counts have been very variable with numbers ranging from zero to 10,000 eggs per gram in the region, and average Strongyle counts ranging from zero to 1600epg between different mobs on the same farm. Worm species have also been highly variable with some farms having almost 100% barbers pole worms while others have 100% scour worms, mainly Trichostrongylus. One farm had 65% barbers pole in one mob and 89% scour worms in a different mob. It is easy to see the value in doing larval differentials from this result. We are also seeing some mobs with moderate liver fluke counts too.

For those producers that have already had significant rainfall, a wormtest is recommended 4 to 6 weeks after, particularly if there has been follow up rain. For those still waiting for an Autumn break, continue to monitor the condition of your flocks, worm test if you think there is a problem, otherwise wait for some rain then test in 4 to 6 weeks.

Bob Templeton, Braidwood, (Bob.Templeton@lls.nsw.gov.au)

Worms very patchy.  Some Ostertagia with the dry and some counts on the way up.  However, in farm differences have surprised a few producers.

Autumn is a traditional Haemonchus time around Braidwood.  Braidwood has just had a lot of rain so the next few weeks will be interesting.

Northern Tablelands Local Land Services

Andrew Biddle, DV Inverell (andrew.biddle@lls.nsw.gov.au)

Patchy rain following our extraordinarily bad summer is not showing too many worm problems.

The only good news is the low levels of parasites and the benefits derived from worm testing and realising you do not need to drench.

For our liver fluke areas we are putting out the message not to forget their Autumn fluke treatments

North West Local Land Services

Ted Irwin, DV, Warialda, (ted.irwin@lls.nsw.gov.au)

At Warialda it has been dry for the most part but storm action has assisted barber's pole survival on pastures and there has been the odd case of anaemia from haemonchosis. Autumn is generally the time when we see the majority of cases but as yet it has been quiet on that front. Most producers are still guessing on their drench choices or relying on advice from resellers. The full extent of resistance to anthelmintics in this area is not known but there is evidence of significant resistance to most of the major drenches, including moxidectin and some triple combinations.