New dairy pregnancy tests
Paul M. Fricke, UW-Extension Specialist in Dairy Cattle Reproduction
Department of Dairy Science
UW-Madison College of Agricultural and Life Science
3:04 – Total Time
0:15 – Importance of pregnant cows
0:52 – Current methods of pregnancy detection
1:29 – New pregnancy test now available
2:05 – How the new test works
2:28 – Better, on-farm tests likely
2:56 – Lead out
The importance of a pregnant cow, we are visiting today with Paul Fricke, Department of Dairy Science University of Wisconsin-Extension in the College of Agricultural and Life Sciences, now celebrating 125 years, and I’m Sevie Kenyon.
Sevie Kenyon: Paul, why is it important for farmers to have pregnant cows?
Paul Fricke: The big concept here is that in order for a cow to give milk she has to get pregnant and have a calf. But I think that what a lot of people don’t think about is that after that cow calves, she’s going to start to lactate and then within about 60 days we’re going to try to get that cow pregnant again. The first two months of her lactation she’s not pregnant and then after that we’re going to try to get her pregnant again and not every attempt at breeding that cow or inseminating that cow is going to result in a pregnancy. So we have to have ways that we can go in to these cows and determine whether or not they’re pregnant.
Sevie Kenyon: Paul how do farmers even know the cow is pregnant?
Paul Fricke: The most common form of pregnancy diagnosis would be trans-rectal palpation and so people that don’t live on farms probably would find this surprising, but a veterinarian is going to reach his arm into the rectum of the cow and then with his hand he’s going to palpate the contents of the uterus and determine whether or not the cow’s pregnant. Another really common thing that’s done with a newer technology is with trans-rectal ultrasound. Again you just take an ultrasound probe, put it into the rectum of the cow and you can visualize the contents of the uterus and determine whether or not that cow’s pregnant, whether she needs to be inseminated again.
Sevie Kenyon: Paul, is there anything new happening in this regard?
Paul Fricke: Yeah in fact there is. In humans they do a test for a certain chemical, it is called human chorionic gonadotropin (hCG). And you can buy that test, like say at Walgreens or at your pharmacy; they are very accurate tests in human’s very early, say as early as day 7. In cattle there’s not a similar hormone. What there are, are these things called Pregnancy Associate Glycoproteins, we call them PAGs, they’re present in circulating blood and milk in a pregnant cow around day 28 to 30.
Sevie Kenyon: So how does a farmer go about then, determining if his cow is pregnant?
Paul Fricke: So the first iteration of these tests were restricted to blood. So you had to take a blood sample for the cow. Now that’s a kind of a tedious process on a farm. So the newest iteration of these tests comes by testing milk. So a pregnant cow is going to have a certain amount of these PAGs in the milk that you can detect.
Sevie Kenyon: Paul, what might the future hold for these methods?
Paul Fricke: I think as these technologies continue to develop we’re going to see, perhaps, earlier testing. We’re going to see the ability to do on farm testing. And the pattern of PAGs secretion is interesting; the tests are most accurate early, around day 32, they get inaccurate kind of in between from day 46 to about day 70, and after about day 74 they get very accurate again. And that’s a reflection of this circulating PAGs in the milk and in the blood.
Sevie Kenyon: We’ve been visiting with Paul Fricke, University of Wisconsin-Extension in the College of Agricultural and Life Sciences, and I’m Sieve Kenyon.