I have used them for the last 3 years with excellent results. It's great for me becaues we have limiited vet service and I work during the week. I can run my animals through the chute on Sunday and mail the tests on Monday. I usually have results by Wednesday I think. It depends how you ship it, they give you the results the day after they recieve them. I choose to recieve the results by email. There are now many more labs all over the country that run their kit. I think their site says they are coming out with an on-farm test.
The downside would be for those who palpate and divert those that are open to the meat wagon immediately.
You take a blood sample, red top vacutainer, mail it, they run an ELISA on the serum. It detects a protein associated with pregnancy. Animals have to be at least 30 days pregnent.
We tried it last year on the heifers with really great success. I just compared the results with my calving record book. The higher the number, the further along in their pregnancy they were. The calving records sure bear this out. We'll be using them again this year.
We have used this program for 3 years and have had good results. I use it to check conception of AI on heifers. There have been a few that were called open by the blood test but ended up calving to the AI date. The test is said to be 95% accurate and that corresponds with our results. Cost is about 2 to 3 dollars depending on shipping and your source of tubes and needles.