I know this is an old thread, but I thought it was very informative and just wanted to also add in some information I came across while I should have been getting ready for bed...
I can't find the source of the image that was linked or the story behind the udder here, besides this
photo collage website which gives absolutely no context except that the cow is in a field somewhere in the Netherlands. There's no evidence that the cow is the result of some planned breeding to produce an udder of this shape. This type of pendulous udder is most likely caused by an injury and is not purposeful, and it indicates imo bad management.
This is a more typical dairy cow's udder.
View attachment 3486194
Also note that for these dairy shows, the cows get 40% of their points based on their udder, and a capacious udder is prefered, but a pendulous one is certainly not. An udder that's high and tightly secured to the body is best, with level teats. High and tightly secured indicates a long milking life. It's better for a milking cow to stay in production as long as possible, and stay healthy throughout.
Dairy bulls are judged on the udders of their daughters, and that's why on most AI sites selling bull sperm, you typically won't see many pictures of bulls. The ones that do have bulls haven't yet produced daughters (brand new to market).
Milk letdown happens in dairy cows too, and it's an important process. Epinephrine (from stress and pain) inhibits this process, so it's extremely important to keep the dairy cows from being stressed. These are extremely valued and cared for animals, even in factory farming situations. A pendulous, painful udder not supported by the suspensory ligaments will not give much milk, if you can even get the milker set up on it.
I've only AI'd slaughter reproductive tracts and fake plastic cows so far. But I can say with borrowed experience (from my instructor) that it's much safer for the cows and humans to not have bulls on property. Bulls can hurt cows way more than an AI depositor can. AI sperm can also be sex selected so fewer male calves are born. Females become future dairy cows, they're not surplus.
So, uh, what ever happened to that poor "rescued" chicken, anyway?