The overall goal of this project is to provide a one-step cow-side test kit for detecting pregnancy in cattle by a serum test. The test is based upon detection of pregnancy-specific protein B (PSPB), a product of the placenta of cows. During the Phase I project, we identified a test-strip of nitrocellulose that would wick serum and readily move colored latex beads to form a color band as an indication of pregnancy. The test takes 3 to 5 minutes. Coating of beads, and the nitrocellulose strips with anti-PSPB immunoglobulin G was accomplished. The formatted test-strip was tested with serum from cattle in various stages of gestation. It was found highly accurate in testing non-pregnant animals. It was effective in detection of pregnant animals in various months throughout gestation. The test detected some pregnant animals as early as 24 days of gestation; however, efficiency between 24 and 44 days increased as time progressed and ranged from 40 to 86% detection. Goals for the Phase II project are to increase sensitivity of the test, identify a test-strip support device, and conduct field trails with a prototype. It is anticipated that the cow-side test will be as accuratet > 95 % correct) and sensitive (28-30 days) as the radioimmunoassay for PSPB in detecting pregnancy.Applications:A radioimmunoassay for pregnancy-specific protein B. the protein upon which this test is based, has proven to be the most reliable chemical test for pregnancy. Conversion of the assay to a user friendly. one-step color reaction will make it feasible for producers to use. It will be more reliable and materials are much cheaper than the ultrasound test which may be as accurate. We estimate that if this test shortens the postpartum interval from calving to conception by just five days it will save the dairy industry 5120 to $160 million annually. We also estimate that the return on investment will be 300 to 667%.
