Writing doesn't do as much as you'd think for long-term fixed preservation of knowledge. It sure helps, but 1) oral teachings exist and useful practices are passed down whether or not they're written, and 2) at the end of the day books need to be constantly rewritten as they wear out, and ancient libraries burned down all the time.

In terms of building a civilisation in the first place, animal husbandry is vastly more useful than writing because writing is something scribes do (i.e. your non-farming elite - in medieval times, more than 9/10 of the population were farmers, and prehistorical farming was likely far less efficient than medieval farming what with the lack of iron etc), and animal husbandry improves your agriculture dramatically and are a major factor in providing the food-surplus for those scribes to exist in the first place.

In fact, particularly food-poor empires tend to be conquered by more food-rich empires that can field larger armies, so if your hypothetical has-writing empire fought my hypothetical has-animals empire then I expect mine would win. Especially since your army wouldn't have cavalry or charioteers.