Milk progesterone concentrations: an accurate early pregnancy diagnostic aid in dairy cattle

The optimal day of milk sampling for pregnancy diagnosis by milk progesterone quantitation was determined as well as the diagnostic efficiency of the test for days 14 24 post insemination in dairy cattle. The results show that on days 22 and 23 after insemination diagnostic efficiencies of approximately 100% can be obtained. Enzymeimmunoassay (ELISA) has numerous advantages over the radioimmunoassay in terms of capital outlay, suitably trained staff, and radioactivity-handling facilities when establishing large-scale milk progesterone testing schemes. A positive and negative predictive value of 93,8% and 94,2% respectively was obtained for this test, both of which compared well with similar parameters for the radioimmunoassay test. With regard to correct diagnosis, prolonged exposure of samples preserved with potassium dichromate to elevated temperatures and sunlight did not affect the progesterone concentration. S. Afr. J. Anim. Sci. 1985, 15: 151 -154