pickled well thinking about the cow teat thing...I mean presumably when you don't have access to clean bottle then it is best to go direct to the source? The bottle only gets a look in in terms of storage...and transportation (I am now picturing the milk round as a process by which a block leads a confused cow around the housing estate).
For humans I personally found a huge decrease in efficiency when you switch from direct to expressing....if you going to feed anyone breast milk it is certainly more efficient to get it direct from the boob.
I think not doing so is just a mechanism to mind sanitize the process...which wouldn't be necessary if we weren't all hung up on boobs and borderline boobaphobic....