Pretty sure that Taktic is a spray/wash on but if using it outdoors, once you have sprayed it on your pigs they may well go role in the dirt/mud/wallow, which means it won't be very effective after that.

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All these products have different withdrawal dates ie Ivermectin which is 21(maybe 28?) days, Panacur which is only for worms, 10 days, etc., so you will need to bare this in mind when choosing a product. Just all depends at what date they are going for sausages, if atall!