This is not always the case. I recall learning during my youth that in Victoria, Australia, the heat cycles and pregnancies of the entire herd were synchronised to that it lead to a period of 6 to 8 weeks where no milking occurred at all.
That's not to say that there was nothing to do on the farm, or it was time to take a holiday, just that the cows did not need milking during that time period, so perhaps it was easier to relax a little.
There are also "contract milkers" who can be brought in for short stints of time, allowing the owners to take time off. Of course there is a cost to this, but I guess that just needs to be budgeted into the overall cost of the "holiday."
The poster upstream suggested there were 6-8 months of downtime with nothing to do. We've gone down to 6-8 weeks with no milking. There's still feeding and watering and of course monitoring a herd of now-pregnant cows with all the possible health complications that come from that.
I'm also relaying my friend's experience, not just speculating. In her circumstances, there was daily maintenance and no vacations. Perhaps her family didn't budget well enough.
That's not to say that there was nothing to do on the farm, or it was time to take a holiday, just that the cows did not need milking during that time period, so perhaps it was easier to relax a little.
There are also "contract milkers" who can be brought in for short stints of time, allowing the owners to take time off. Of course there is a cost to this, but I guess that just needs to be budgeted into the overall cost of the "holiday."