Not milking a dairy cow, can cause a lot of problems. A dairy cow will produce about 8 gallons or 30 litres a day. Adding to the problem of not milking is the missing calf, as they are normally kept separately to ensure higher milk yields.

If you stop milking this cow altogether, milk production will continue until the pressure starts to build up. This process normally starts a dry up phase, which will prevent the cow from producing more milk.

Because of modern breeding practices, it’s impossible for dairy cows to dry up naturally in a high production phase before facing serious problems. As, extending this phase increase the milk output of a cow, making it more profitable to keep this state as long as possible.

For those cows, stopping to milk them will cause the udder to increase is size until it can not expand any further. This cow will be in serious pain at this point. Caused by the enormous size of the udder it will also be in the way of everyday activities, preventing the cow from properly standing, sitting or laying.

If pressure still isn’t released then the udder can rupture or get infected. Ultimately leading to the death of the cow, if she is not treated and pressure is released.

https://farmityourself.com/what-happens-if-you-dont-milk-cows/