Development of a Competitive Lateral Flow Immunoassay for Progesterone in Dairy Cows' Milk

The routine monitoring of progesterone, a hormone that plays important roles during pregnancy, has become increasingly important in dairy cows. In this study, 11 alpha-OH-progesterone-hemisuccinate-BSA was used to immunize Balb/c mice for the preparation of mouse anti-progesterone monoclonal antibodies (mAbs). A competitive lateral flow immunoassay for progesterone was developed with the use of purified mAbs. Standard progesterone solutions or milk samples containing different concentrations of progesterone were added to the sample pad of the test strip. A bright or weak test line represented progesterone levels < 3 ng/mL and no pregnancy; a very weak test line was indicative of 3-5 ng/mL progesterone and the need for further pregnancy diagnosis; no test line was indicative of pregnancy. The characteristics of the test strip make it ideal for early pregnancy diagnosis.