At least eight different milk progesterone assay kits are not on the market.
Progesterone is high during midcycle and pregnancy.
Lower levels are detected two or three days prior to heat, during heat and for a few days after heat. Knowing the level of progesterone can be of value in determining the reproductive status of a cow. This technology can be used to verify suspicious heats, evaluate the accuracy of heat detection on a herd basis and identify cows that are not pregnant 19-23 days after insemination. There are several other uses of milk progesterone analysis which can be used in cooperation with your veterinarian to diagnose certain problems. If you are interested in trying this new technology, buy a kit that has a small number of tests per package so that you become familiar with the procedures and determine if you like it before investing too much money.