Whole milk progesterone analysis used for pregnancy diagnosis in beef cattle.

In Finland the routinely used method to determine milk progesterone level is based on whole milk analysis (Progesterone RIA-kit for Veterinary Diagnostic use, Farmos Group ltd.). The method is standardised for milk samples which are taken from the udder just after the cow has been milked. This kind of aftermilk sample contains a high percentage of fat and–as progesterone is lipidofil–also large, sexual-cycle correlated, variability in milk progesterone.