Latest news on horse wormers is that Equest Pramox a tapeworm and redworm treatment for horses made by Zoetis is now licensed for breeding, pregnant and lactating mares. Equest Pramox can also be used in foals from 6.5 months of age and stallions and mares. This is good news for some horse owners who have had to put some horses on a differing worming regime if any horses have been pregnant.