“I always feed the dog at 5:30 pm. When DST goes into effect, I still feed the dog at 5:30 but for the first few days he doesn’t seem hungry right away. What’s with his brain?”
I’m chuckling because although I have had the privilege of having several dogs, I can't read their brains! My guess is that animals and other creatures typically continue to follow the Sun time—and don’t keep checking with the Clock time (if they have even learned to notice where the “hands” are on the clock at any one time). The dog’s brain, at least for the first few days, may wonder how come you’re putting the food out earlier than usual (remember that 5:30 pm Sun time is now 6:30 pm Clock time. My dogs typically adjusted and then all of a sudden (to them), we’re back on Sun time. It’s really quite laughable if you have a good sense of humor and your brain has figured it out. For me, the "Spring forward" into DST is always like a mild case of Jet Lag.