Removing feces from paddocks dramatically reduces parasite burdens, as it constantly removes the source of infection. | Photo: Alexandra Beckstett/The Horse

Q.Many articles are about deworming horses and how worms are getting immune to the dewormers we’re giving them. But how about an old dewormer: diatomaceous earth? Worms will never get “used” to this dewormer because it slices the worms into small pieces. Every morning for about two months in spring and fall I add one heaped spoon of it to my horses’ feed.

The larvae-counting manure test does not tell the whole story, as the test cannot count what is left behind in the intestines. In concert with my vet, I had one of my horse’s blood tested before the diatomaceous earth and after. Before he tested high on worms. After two months his blood count was back to normal. Mind that I remove the manure from the paddocks every day.

—Irene Louw, The