The isolation of non pregnant cows in a commercial dairy herd represents a substantial cost to the farmer. The majority of cattle pregnancy diagnoses (PD)'s in the U.K. are made from rectal palpation or by the use of (a) milk progesterone (b) milk oestrone sulphate or ( c) blood progesterone tests. A D.I.Y. pregnancy test has obvious advantages, namely:-

1. 1. Tests can be performed by farm stockmen at their own convenience.

2. 2. Diagnosis is made immediately.

3. 3. Tests can be made through complete pregnancy term.

4. 4. After initial capital outlay for equipment, the cost of tests is negligible.

Such an alternative is the doppler ultrasound (DOP) system (per rectum) which utilises audible changes in frequency of ultrasound between the transmitted signals and their echoes when moving surfaces are contacted.