HOW TO USE THIS ONLINE MAGAZINE
by clicking the arrows at the side of the page.
by clicking anywhere on the page. A slider will appear, allowing you to adjust your zoom level.
and move the page around when zoomed in by dragging the page.
and return to the original size by clicking on the page again.
by entering text in the search field and click on "In This Issue" or "All Issues" to search the current issue or the archive of back issues
a PDF of this magazine.
by clicking on thumbnails to select pages, and then press the print button.
a page via email, Facebook, Twitter and more.
TO VIEW PREVIOUS EDITIONS
, click the
button at the bottom of the screen.
Beyond the Bale : September 2014
48 ON FARM MORE INFORMATION For help with drenching decisions and regional worm control programs, woolgrowers can refer to WormBoss at www.wormboss.com.au The recently-released results of a 2011 national survey of practices used by Australian sheep producers to control worms, flies and lice, highlight that many producers have not fully embraced an effective and sustainable approach to worm control. The survey, completed by over 1000 sheep producers across Australia, was conducted by Professor Steve Walkden-Brown and Dr Ian Reeve from the University of New England. AWI and MLA have supported the study, which provides a good national perspective and comparison to an initial survey of nearly 2300 producers in 2003. The number of worm treatments given to adult ewes across the nation averaged 2.1 in 2003 and 2.7 in 2011 with most treatments given in the New England region of NSW (see Figure 1). This is a region endemic for barber’s pole worm and it received 1000mm in 2011, which was 200mm more than the annual average. Pleasingly, the number of combination treatments used in 2011 was 43%, which is an important means of controlling drench resistance. A combination contains two or more active ingredients (eg albendazole + levamisole) that each target the same worms. The chance of a worm being resistant to all active ingredients in the combination is much lower than for each individual active on its own. Of concern was that the remaining 57% were single active treatments, with moxidectin and ivermectin most likely to have been given alone. Monepantel (Zolvix) was also mostly given alone, but it is not available as a combination treatment. The best time to use combination treatments is before drench resistance emerges. The factors most commonly nominated as very important for deciding if worm treatment was required were worm egg counts, time of year, and, in barber’s pole regions, exercise intolerance. Worm egg counts were used by only 21% of producers in 2011, despite being seen as very important, which was lower than the 44% of producers who used worm egg counts in 2003. This was disappointing as worm egg counts can give an early warning of production loss before signs are obvious. Drench resistance testing has been conducted in the last five years (2007–2011) by 29% of sheep producers, unchanged from 2003. Drench resistance is said to be present when a drench causes the egg count to be reduced by less than 98%. Only 55% of producers thought they had resistance to benzimidazole and levamisole drenches, 12% thought they had resistance to ivermectin, 28% to abamectin and 21% to moxidectin. On average, 48% of sheep producers said they didn’t know the drench resistance status of drench groups on their farms. When compared to actual resistance test results, this suggests that many sheep producers either underestimate or don’t know the extent of drench resistance on their farms. A recent compilation of the results of 390 resistance tests on Australian farms was carried out by Playford et al (accepted for publication in Australian Veterinary Journal). This reports that resistance against benzimidazole and levamisole was present on 96% of farms, and against ivermectin, abamectin and moxidectin on 87%, 77% and 54% of farms respectively. These conflicting estimates of drench resistance highlight the need to test for drench resistance and to schedule these tests every 2–3 years. Drenching remains the main technique to control worms, used by 87% of sheep producers, but paddock spelling, cropping and cattle/sheep alternations are all well used with importance varying among regions (see Figure 2). Integration of a range of worm control techniques is an important component of a good worm control program. There was a low use by sheep producers of worm-resistant rams, selected using Australian Sheep Breeding Values (ASBV) for low worm egg count (see Figure 2). On average, 13% of producers used rams selected for resistance to worms but only 62% of these rams were selected on the basis of ASBV for worm egg count, which is the gold standard. Introductions of sheep occurred on 57% of properties and some form of quarantine worm treatment was given by 67% of producers. Ideally a quarantine treatment should include a combination of no less than four unrelated drench actives, with one of these being monepantel (Zolvix). In contrast, most producers used a single active drench for sheep introductions, which leaves the risk of importing drench resistant worms onto the farm. NATIONAL SURVEY HIGHLIGHTS Figure 1 Number of treatments given to adult ewes in 2003 and 2011 within each region. Figure 2 Percentage of producers using various worm control techniques within each region. Note that rams with ASBV relates to selecting rams that have ASBVs for low worm egg count. WORM CONTROL PRACTICES An AWI and MLA supported national survey has reported the practices used by Australian sheep producers to control worms, flies and lice. • The percentage of producers using worm egg counts has dropped from 44% in 2003 to only 21% of producers in 2011, despite the practice being seen as very important. • The number of combination treatments used in 2011 was 43%, which is an important means of controlling drench resistance. Numbertimestreatedperyear 0 SthQLDNewEnglandNSWCentral&SthTablelandsNSWSthNSW&NthVICWestVIC&SESASthSAKangarooIsWA 2003 2011 1 2 3 4 5 6 Producersusingwormcontroltechniques(%) 0 SthQLDNewEnglandNSWCentral&SthTablelandsNSWSthNSW&NthVICWestVIC&SESASthSAKangarooIsWA Spelling Crop Cattle Rams with ASBV 20 40 60 80 100