Cats/dogs & poison ivy: allergic/poisoning possible from grooming contaminated fur?

People are almost the only animals that are allergic to the urushiol (the active moiety in poison ivy/oak) in the plants. Moose, elks, deer, and birds seem to be immune to urushiol and in many areas, poison ivy is a good source of nutrition for plant-eating animals.

However, caution is needed when it comes to dogs and cats because exposure to urushiol infrequently can still result in skin irritation, although not as much as humans.

For a more scientific explanation :-

Chemically, urushiol is a mixture of eight 3-substituted pyrocatechols. The compound shown is the C17 diene, an important part of poison-oak’s arsenal.

Urushiol is a strong reducing agent. Oxygen in the epidermal layer of the skin transforms the urushiol to an orthobenzylquinone.

The immune systems of animals in the last 60 million years have ignored small metabolically-common molecules, like the six carbon ring of pyrocatechol. Animal immune systems have concentrated on foreign molecules larger than 18 carbons, and respond most briskly to compounds in the 21 to 23 carbon size range. Septadecylorthobenzylquinone is such a compound; it never originates in animals, and has 23 carbons. A few molecules of it can cause a rash

I don't KNOW if animals are DIRECTLY affected by poison ivy, but I DO KNOW that humans, who are sensitive to it, can get a rash from the fur of animals who've come in contact with it!

I speak from experience on this!!

Maybe you should ask a vet about animals being affected by poison ivy.

Good luck............