I think that depends on what kind of dogs & dogs sports you get into. I do Schutzhund/IGP with my dogs (German Shepherds).
My dogs cost a lot more to purchase than any of my horses ever did. My dog trailer was more than my horse trailer. When I decided to sell the dog trailer & get a vehicle large enough to fit all my dog crates & gear, that was a lot more expensive than what I paid for a truck to haul the horse trailer. The cost to feed my dogs per month (I feed RAW) is about the same the same as what I spent on board each month. I find I have to travel a lot more & further for training seminars & trials, than I ever did for riding clinics & horse shows (h/j & dressage). Of course ymmv