Well looing at it biologically you should avoid certain types of animal like bears. Zombies are dead creatures, a bear would have to be stimulated differently to attack as they do not eat dead meat. No I think I'd go for something tropical, a rino. those you can enrage simply by plopping the zombie in their territory.
It's about what animal you would want to see fight a zed, and if I remember correctly an animal would die if infected. A bear does not eat dead flesh but a rhino would charge at virtually anything that enters it's terrotory.