Interesting article entitled
Dog Out Bag – What You Need In A Dog Survival Kit
https://thepreppingguide.com/dog-survival-kit/There are "where to get" links for for the DOB and a collapsible food/water bowls.
Two bag brands are listed Mountainsmith and Tigris Tactical.
The Tigris is 10x1.8x7 which is 126 per side -- 256 cu in for both sides
Mountainsmith
Small dog - 860 both sides
Medium dog - 1460 both sides
Large dog - 1860 cu in both sides
Not a bad idea if you have a dog that goes with you. Both of you can take walks to get in shape and used to the weight.
The only other thing I'd think about with a dog would be a light weight cart for them to pull instead of a pack.