I just Googled Potassium Iodide in regard to pets. My pup is a big part of my preparedness planning.

http://www.aaoobfoods.com/nbcinfo.htm#pets?

Can I give it to my pets?

There have been no studies concerning animals and the administration of Potassium Iodide for radiation emergencies. Like humans, animals do not normally have any allergic reaction to limited doses of Potassium Iodide. For animals with no known iodine allergies (ask your vet) it is a relatively safe drug. If you wish to administer potassium iodide to your pet, follow the Iosat dosing chart amounts listed above in the "What is the dosage?" info and give the appropriate dosage based upon weight. For instance, the dosage for a 2-year-old child would be 32mg (1/4 tablet). If an average 2-year-old weighs 25 -30 lbs., a dog weighing the same would take the same dosage, 32mg (1/4 tablet). If a 2-week-old infant weighs on average 9 lbs., then you would give a 9 pound cat/dog 16mg (1/8 tablet). Crush it up and put it in their food. Please consult with a vet in advance to make sure your pet can safely take Potassium Iodide.

Note: Iodine is found in table salt, fish oil, kelp, daily vitamins, etc.)