We all want our hounds to be healthy and parasite free, but do we really know what is in those little foil packets that we routinely force into our hound's blood stream - with nothing but the best of intentions. If we learned for example that we were dosing our dogs with pesticides containing (amongst other things) neonicotinoids, known to profoundly affect the nervous system of bees when they visit plants for nectar on fields or crops which have been sprayed. Knowing this might make us stop and consider alternatives.
This video sheds a little light on the subject of alternatives which you may like to consider.