Fresh cows should never enter the hospital pen with sick cows or be milked with the hospital string. Cows, which have just freshened, are very stressed. Just prior to and after calving, cows are perhaps the most susceptible to new infections of all kinds. This is particularly true for mastitis. It is too easy for the hands of the milkers or the milking machines to become highly contaminated with mastitis bacteria or mycoplasma and for these organisms to be transferred to the fresh cows.
Many mycoplasma outbreaks start in the hospital pen when fresh and sick cows are mixed.
The cows in the hospital pen are also under stress due to their illnesses and their immune systems are not functioning at maximum potential. Therefore, these cows are also highly susceptible to getting further infections from other cows in the hospital pen. The most competent and reliable milkers should be assigned to the hospital pens to insure application of excellent milking techniques. Only single use, disposable towels should be used to wash and dry udders. Teats should be dipped and not sprayed after milking to guarantee maximum teat coverage.