Hiya
Firstly thank you for asking dairy farmers. Sadly it looks like you have had lots of replies from People who get their information from vegan websites which are incorrect.
No what you have shared isn't factual. Bull calves are not shot at birth. Yes they used to be 30 years ago. We now don't shoot calves. We don't want to, we aren't allowed to. They are reared for meat.
Yes on many dairy farms calves are removed at a young age. However this is to protect calves, ensure they get the correct amount of colostrum and look after them correctly. Many dairy cows are rubbish mums, don't feed their calves properly and would happily leave them to die in a hedge.
Cows aren't constantly pregnant and milking. They have breaks.
They are not worn out by 5 years old at all! Most herds have cows up to (and over) 10 years old. Most cows don't survive until 25 in the wild.
Artificial insemination is done because using bulls can be dangerous for both the farmer and the cows. The damage caused to cows can be horrific. We also used sexed semen to reduce the number of males born. AI is nothing like rape. Its done then the cow is bulling and receptive to being mated. They will happily stand and let you do it- they want to get in calf.
If in the wild they would be mated a lot earlier then we Ai them and would not have any break between pregnancies. Bulls crack on whenever they want.
No we no longer breed for milk volume. Most milk contracts are now about milk quality. Butterfat, protein etc are more important then extra litres.
Our cows are well looked after. They have great lives.... better then ours. Their health and welfare is monitored 24/7. Please message me if you have anymore questions as I might miss them on here.