A couple of well placed access points on the farm and this whole thing could be done with wifi. No need for big monthly bills from the telco for connecting up a couple of hundred head of cattle. Hell, RFID will tell you which cow just came through the door.
Dairy cows don't travel far. they need to return to the milker each morning and evening. That means they are within walking distance of the barn so that drastically reduces the area that you need to cover down to less than 100 acres, most likely 20 or 30 will do. Moreover, the cattle are likely to be in open field, so that make communication even easier.
This is just overkill for the need and over hyping 5G