My dh has tanned hides for over 23 years. He mainly tanned deer, some elk and other hides. He tanned the way his grandmother/tribe taught him using brains and water. Cow hides are HARD to do, they are very thick. Commercial tanneries use terrible chemicals to tan the hide. If you can get the brains to go with it check out
www.braintan.com for pointers on how to tan. They use lye/KOH to slip the hair which my dh has never done. Cow hide would be good for moccasin/shoe soles and heavy bags. If you pare it thin enough it could then be used for baby shoes/moccasins. If you scrape it within 24-48 hours of butchering the smell isn't any worse than raw meat, longer than that, yuck! If you know of any mountain man/rendezvous enthusiasts in your area they would be able to give you some pointers as well.
Good Luck! and Best Wishes if you decide to tackle the project.
Sarah