RESEARCH has shown that yearling steers either not treated for worms, or treated with an ineffective product, were 10 kilograms lighter after 28 days, and 15kg lighter after 90 days.
The trial, conducted jointly by NSW Department of Primary Industries and Local Land Services, and supported by Virbac, involved around 40 steers in each of six treatment groups. They were weighed seven times over the course of the trial, while faecal samples were collected on five occasions from a subset of steers in each treatment for worm egg counts and larval identification.
The data showed that the doramectin pour on product was ineffective at controlling worms and so weight gain and WECs were similar to untreated animals. The effective treatments included oxfendazole, levamisole, moxidectin and the dual active moxidectin + levamisole products.
Farm Manager at the NSWDPI Duck Creek Research Station, between Ballina and Grafton, Michael Beaumont, believed that the results would have major implications for worm control along coastal NSW.
"We initiated the trial because we wanted to provide relevant information for local producers and for those providing advice around worm management programs," he said.
"The results clearly show that worm resistance is becoming an important issue for coastal producers and that product selection can have a big impact on economic outcomes. At nearly $4.50 per kilogram liveweight the wormy steers were worth $65 less at the end of the trial."
According to NSW Local Land Services District Vet at Casino, Liz Bolin, the options available to producers are clear: "Firstly, producers should have a worm control plan, because if they don't it is costing them money. Chemical control is an important part of that plan and includes using a combination of active ingredients to control worms.
"This might include one of the dual action pour on products, but could also include a combination of an ML product plus an oral product containing a clear eg levamisole or white eg oxfendazole drench. But it is also important for producers to reduce the selection pressure and prolong the life of the ML active ingredients by using alternative products where possible, when controlling other pests such as ticks, lice and buffalo flies."
NSW DPI Beef Development Officer Todd Andrews said the project revealed a couple of surprising results.
"The crossbred steers were on good ryegrass and were averaging around 1.3kg/hd/day in the two weeks prior to treatment. However, after treatments were applied, the steers included in the trial were separated from a larger mob and then treatment groups were also separated for three days," he said.
"The stress of the social dislocation combined with the worm burdens meant that weight gain in the control and doramectin treatments dropped to 0.5kg/hd/day, around half of the other steers, in the two weeks after treatment. This suggests that worm control at stressful times such as weaning but also when buying new animals, is likely to have the biggest impact."
The other really good outcome for beef producers from this trial was that the older products such as levamisole and oxfendazole were still effective and so may provide back-up options for worm control in cattle, Mr Andrews said.
"We have seen in the sheep industry where worms resistant to multiple active ingredients greatly reduce control options and animal performance and so increase direct and indirect costs to producers," he said.
The major worms identified in the project were Haemonchus (barbers pole worm), and Cooperia.
Unlike the blood sucking Haemonchus, drench resistant Cooperia did not affect steer weight gain in this trial.
Senior Technical Services Manager with Virbac Australia, Matt Ball said: "The beauty of this research trial is that it included both weight gain and WECs and included young commercial cattle from a range of properties under documented conditions."
He suggests that although the economically important worms in other regions might be slightly different, the result is a warning to cattle producers across Australia: that using ineffective drenches costs money.
"This trial is consistent with other research showing that resistant worms reduce cattle productivity," he said.
"All cattle producers should seek advice to identify their key parasite threats and then choose the most effective drench to protect productivity. In this trial a dual active product containing moxidectin and levamisole was highly effective against all key worms. Cattle producers should include a combination of chemicals in their drench program, eliminate unnecessary chemical use and utilise a Faecal Egg Count Reduction Test (FECRT) every 2-3 years."
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