Every cow is different that does not prevent them from being treated as a commodity. "In economics, a commodity is a marketable item produced to satisfy wants or needs. Often the item is fungible. Economic commodities comprise goods and services. https://en.wikipedia.org/wiki/Commodity

Staff ex:Nurses are generally treated as a commodity in many economic models.

Music/Books/Movies can also be treated like this. Sure, as a consumer I might pick A over B, but movie theaters don't individually price movies based on quality.

They can be treated as a commodity as they are graded on value. How would a commodity market work if each instance of the commodity had a different value? Both live steers, and their resulting leather, beef and other byproducts are sold based upon weight and/or grade.

For example, 'a cow' is not a commodity... but a grade 3 live steer is.

Movie theatres do not price films based upon quality, but the distributors certainly do (I managed a movie theatre). You cannot commoditise a movie ticket, each theatre provides different facility and presentation quality.

Sure, cattle auctions sell the animal for an individual price based on health, weight, body size etc. At the extreme end animals can sell for 150,000+ if they seem to have good DNA for breeding. http://www.syracuse.com/news/index.ssf/2013/03/bovine_beauty... Even if there just being butchered people make bids based on expected yields. This gets back to meat grades etc.

However, animals are also sold in bulk without individual prices.