Bruce Watt, Senior District Veterinarian, Tablelands LHPA, Bathurst NSW 2010-11-17
The late wet spring most of us are experiencing has been great for stock and great for worms (and blowflies). We have seen some very high egg counts and even deaths from winter worms in sheep and even some losses from barber’s pole worms.
We know that worms also affect the growth rate of young cattle but this may not be obvious. Young cattle should therefore be drenched now unless they have been treated in the last two months. Unfortunately, worm egg counts are of limited value in helping to determine the need to drench cattle.
On the other hand, worm egg counts are very useful in sheep. If you haven’t drenched your sheep recently you should prepare either to drench them shortly or to submit manure samples to a laboratory to check the egg count.
A neat piece of research conducted over forty years ago in western Victoria show why drenching now is important. Norman Anderson, a CSIRO scientist ran young previously worm free sheep on pastures for about a month, then removed them and replaced them with the next group of young sheep.
He then killed the lambs and counted the number of worms they picked up from the pasture throughout the year. He found that sheep picked up loads of worms each month from April until mid October. He then found that after mid October these ‘tracer’ lambs picked up very few worms.
Of course, western Victoria is not the tablelands of NSW. In many years, more worms are available on pastures over the summer here. However, some of the principles still apply.
This and other research has contributed to our recommendation to summer drench, once about now and once in 2-3 months time. However, we modify this recommendation depending on circumstances. If you treated your sheep with a highly effective pre-lambing drench, they may not require this first summer drench. Worms egg counts help here. If the worm egg count is lower than about 100 you can delay drenching but in a season like this will need to keep monitoring closely.
I often talk to producers about worm egg counts and when they should drench based on these counts. This is not yet an exact science. However, in general we can tolerate a higher worm egg count (say 400-500 epg) in ewes in top order on very good early spring feed. Conversely, a count of even 100 may be too much in struggling merino weaners on poor pastures.
The other factor to consider is the time of the year. In late spring/early summer, we tolerate a much lower egg count because we need to keep in mind that worms deposited on pastures now and over the next few months into the autumn will contribute to parasite problems next winter and spring. We also need to nip a potential summer barber’s pole worm problem in the bud with a drench now.
Some producers also achieve good worm control with rotational grazing or by alternating pastures with cattle. However, in general, at this time of the year I would recommend that sheep owners drench if egg counts are over 100 epg.
If you are one of the many producers who has never utilised worm egg counts let me explain how it is done. First, pick up a worm testing kit. LHPA and I&I offices have the containers that you can post. However, some private laboratories and veterinary practices also provide this service.
Muster the mob you wish to test and hold it in the corner of the paddock (but not the sheep camp) for about 10 minutes. Then pick up fresh manure samples from the area and place them in the bottle contained in the kit. Mail off the kit and expect results in 2-3 days.
A reminder that we are hosting a discussion on grass tetany or hypomagnesaemia. Mac Elliot who is a livestock officer with I&I has developed some insights into using soil testing and weather data to help predict the likelihood of hypomagnesaemia. Mac will speak at a meeting at the Hampton Halfway House at 2:00 on Wednesday 24th November. If you would like further information please call Jeff Eppleston or me on 63 31 1377 or Matt Ryan on 6359 3242.
Interesting case of lungworm in sheepWe recently had a case near Scone with about 40 deaths out of 500 lactating ewes. The sheep in the mob were in just fair condition. Death usually occurred 2 to 3 days following symptoms of heavy breathing and the occasional cough. Condition deteriorated slightly but was not a feature. Sheep had been drenched with ‘Cydectin’ (moxidectin) in May (some may have got Combat (naphthalophos)) and then in July they were drenched with Combat ( not registered for lung worm).
Lambs( on the ewes) and wethers in other paddocks have not shown symptoms.
Since diagnosis, ewes and lambs were drenched with Triton (ivermectin/BZ/LEV) and injected with oxyterramycin. Initially there were a few deaths from pneumonia but all is looking well now.
Unfortunately ewes with their lambs( 2-3 mth) need to go back into the problem paddock and will need further drenching. By the size of these worms (up to 10cm) see attached photo it must take some time for the worm to grow and block air ways.
This certainly was an interesting case with lung worms well of the radar.
Cheers Ross District Veterinarian
Mid Coast Livestock Health and Pest Authority
Singleton NSW Photo: Ross Kemp. Used here with permission. Comment SL): Lungworm is usually not a big issue in sheep in Australia. Usually they are individual cases in a mob and usually associated with intercurrent disease, eg other causes of illthrift (other nematodes etc). The case / mortality rate cited above (~8%) is unusually high for lungworm under our conditions. There were no other obvious problems in this mob eg foot abscess, metabolic diseases etc. The necropsied sheep did have a high worm egg count (larval culture not done), but faecal samples taken from other animals in the mob did not reveal high worm egg counts.
Open Day on livestock research at CSIRO Armidale For the first time in nearly a decade, CSIRO’s FD McMaster Laboratory in Armidale, NSW, will hold an Open Day to showcase its significant recent achievements – including its progress in breeding sheep that are resistant to blowfly strike. To be held from 10am on Friday, 10 December 2010, the event is an opportunity for livestock producers and interested members of the general
public to learn about CSIRO’s research. Read more at: http://www.csiro.au/news/CSIRO-Armidale-open-day.html Extras
Productivity in 11 Words http://www.skelliewag.org/productivity-in-11-words-1040.htm One thing at a time.
Most important thing first.
Two Reasons Why It’s So Hard To Solve A Redneck Murder:
Wally on how to conduct yourself in meetings http://dilbert.com/strips/comic/2010-11-16/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+DilbertDailyStrip+%28Dilbert+Daily+Strip%29 For those who hate Arial ;-), this is in Calibri. Are sans serif fonts all they are cracked up to be ?? Regards, SL