I put them on the compost pile turn them under and let er rip... The dogs find them a couple days later and it is granola poop city for the next few days. Never been any issue.
actually i haven't heard that grains are bad for dogs. hops on the other hand i have heard can make your dog sick. so keep them away if you use any mash hops.
that being said, mash hops will totally screw up your compost. the antibacterial qualities of the hops will literally make a stripe in your compost that won't decompose. i've never tossed the hop sludge from my kettle on there, but i assume they would do the same thing.