ANIMAL HEALTH
A deep dive into drenching Beef finishers should ease up on the drenching to avoid the likelihood of drench resistant parasites, writes Ben Allott.
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eef finishing or dairy heifer grazing systems present a number of challenges around parasite control. The high stocking rate of a single stock class under rotational grazing leads to a rapid rise in parasite challenge if drench intervals are not kept tight and regular. Meeting high liveweight gain targets is usually necessary to meet dairy heifer target weights or to maintain a profitable finishing model. Because of these factors it has become common practice to drench young cattle monthly through large parts of the year. My blunt, honest assessment of an intensive cattle system that finds itself needing to drench all young cattle
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once monthly is that your system is unsustainable. This high level of chemical input is creating drench resistant parasites in a big way. If you want to be able to continue finishing young cattle or rearing dairy heifers, you need to find a way to reduce the amount of drench you use. You need to develop a plan to incorporate refugia into your parasite management plan. Refugia involves keeping a population of susceptible worms on the farm which can slow the build-up of parasites resistant to drenches. In the same breath, you need to do this while maintaining a high level of performance. Simply drenching less frequently will usually not help you achieve this and the production cost can be large.
One idea you should explore with a trusted animal health advisor is developing a targeted selective treatment (TST) programme. An example TST programme could run like the outline below. However, it is important to get good farm specific advice prior to implementing a programme on your farm: • The decision on whether to drench an animal or not is made based on the individual average daily gain (ADG) since the last weigh event. Animals that have achieved a high ADG are left undrenched. Animals with a low ADG are drenched. • You continue to bring all young cattle into the yards at set, regular intervals for a weigh event. At each weigh event some
Country-Wide Beef
May 2021