My K9 Tactical Defense Unit (TDU) has failed at just about every "mission" related job given to her... but she's kind and loveable and a family member to me.  

A search didn't really reveal preps for animals.  

Is there any wisdom out there about long-term storage of dry dog or cat foods?  

The Kirkland brand dog food from Costco has a best by date around a year out.
So I keep a good supply in sealed containers to keep the rodents away and rotate through it.

Heh..pets ARE preps. lol..there are some good recipes for dog on the net.

Your K9TDU should look into diversification.  Our TDU's also function as the Kitchen Floor Spill Clean-up Team (KFCUT) and the Alternative to Electric Blanket Squad (ATEBS).

For storage, we have 2 full-sized garbage cans (with tight-fitting lids) in the garage.  One is always filled with dry dog food, and the other is in various states of fullness as we use it to refill the dogs' food can (~ 4 gallon popcorn tin) that we keep in the kitchen.  And of course we rotate them –– the big cans, that is.  I don't rotate the dogs.  

I plan to add another garbage can-full soon.

have to be careful, as the fats in even dry dog food shorten it's shelf life...  

but yeah - we always have an extra 50 pound bag on hand...  once one gets opened and dumped into it's tupperware storage bin, a new one takes it's place in the closet.  that gives them about 2.5-3 weeks of food, depending on the weather.

buckets with gama lids

I also did a few bags of mylar and o2 just because, I will switch every year.

At my costo they had those big dog food barrels with gamma lids, normally sell for 70-100 bucks, at 25. A 6 gallon bucket with gamma lid is a ton cheaper 15 bucks tops.

ETA I buy the good stuff so its more condensed than the cheap crap at walmart, less storage

We have 3 cats and I've wondered how to store food for them.  We generally have an extra 20lbs bag on hand, which will last them ~3 weeks.  I have considered using a FoodSaver to vacuum-seal some of it.

We use the Iams original cat chow and it generally has a best by date of ~1 year out from when we buy it.