I've been making this stuff for over 20 yrs. I'd say the best stuff smells more like some sort of fruit juice. I just can't narrow it down to a specific type, but a sugary sweet smell, potent at times. But people smell things differently, so what may smell bad to some, smells sweet to others. Ask 5 people to smell the same bale, and they'll all describe it differently.
As for the stuff you are feeding, it wasn't sealed properly, nor was it the right moisture going in to begin with. I'd be taking it up with whoever you bought it from. Cows will eat some pretty rank bales, but you shouldn't be paying to feed that to them. Some white mold is fine, as even a well wrapped bale, where you use a bale squeeze, will sometimes leave a small pocket of air at the squeeze point, and mold there.
So yes, cows will eat some pretty poor stuff, and even act like they like it. But if you want to be serious about feed like a dairy farm is, you can get pretty particular about how its made and how to do it right. Mine is far from all perfect, but I do try my best rather than use the old phrase "well a beef cow will eat it"
Whether its a dairy cow, an athlete, or even an old beef cow > good food in = equals good results out.
And we know ourselves, a lot of the best tasting food isn't too great for us.