If you have horses or cattle and dogs, be aware that ivermectin, a common ingredient found in equine and bovine deworming products, can be deadly to some dogs.

Although not all breeds are affected, corgis, border collies, Australian shepherds and other herding dogs that have a multi-drug resistance (MDR 1) mutation can die from ingesting only a small amount of ivermectin — even residual amounts found in feces.

Since this mutation makes these breeds hyper-sensitive to drugs, they can also be poisoned by several other medications that are harmless for other breeds. Consult your veterinarian for more information.