For simplicity, animals can be fed by purchasing standard rations in settlements. Iron rations can be used for longer journeys. Typically, the monthly cost in standard rations can be calculated and added to the character's upkeep. Of course, on a long journey through the wilderness, provisions (probably iron rations) will need to be properly listed out, weighed, and paid for.
The daily cost of a standard ration is 0.43 gp, or 8 sp 6 cp.
These are listed at WSG 90-91.TODO: Add table here.
If somehow a character acquires a sabertooth tiger, it will consume 8 rations and 5 skins of water per day.