[Sex steroids and pregnancy diagnosis in cattle--tests on the farm].

The peripheral blood and milk contain two steroids, whose concentrations can be monitored and used as a tool for pregnancy diagnosis in cattle: (1) Progesterone of maternal origin, which must be assayed between days 21-24 after Al, allows very early diagnosis of non pregnancy or of gestation onset, (2) Oestrone sulfate secreted by the feto-placental unit is a good means for confirming pregnancy over 110 days after Al. Both steroids have been assayed in a very high number of samples by RIA in so-called centralized diagnosis laboratories. These have many advantages and usually are of a very high standard. Accuracy of these diagnoses has been evaluated in a large number of experimental series and is well known (93-100% for early non pregnancy diagnosis). EIA kits for progesterone have been on the market for 2-3 years. But a more simple test to be used by the farmer himself is now available. It is a so-called dipstick test (Bovitest - ND - Clonatec), including control and test pads on the stick itself plus the conjugate and a soluble substrate. Reading and interpretation ar made by single observation according to the intensity of the blue colour on the test pad compared to that on the control. There is a good agreement between the results of the RIA procedure (used as a reference) and those of this dipstick test. A field study on a quite large basis was undertaken to evaluate the accuracy of the diagnosis made according to this on the farm test. It was very similar to that found by RIA.(ABSTRACT TRUNCATED AT 250 WORDS)