Preg Checking: Blood test allows producers to pinpoint open cowsWritten by Gayle Smith
Laramie – Producers can use a simple blood test to detect pregnancy in their cows, which allows them to pinpoint open cows and make management decisions for those cows earlier than conventional preg checking. In fact, the test is so simple that producers can draw blood themselves and send the samples to a laboratory for testing.
“The test is 99 percent accurate in determining open cows,” says Tanya Madden of Eagle Talon Enterprises, LLC. Madden operates a laboratory in Laramie, where she analyzes the blood to determine if the cows are pregnant. The blood test, known as BioPRYN, was developed in 1992.
Madden grew up on a ranch in the Black Hills of South Dakota. She holds a bachelor’s degree in molecular biology, and a masters degree in animal and veterinary science. She started Eagle Talon Enterprises a few years ago, after becoming interested in performing ultrasounds on cattle. Her business expanded to BioPRYN after visiting with ranchers about ways to improve the profitability and efficiency of their operations.
“It was probably a year after I started looking into BioPRYN before I added it to my business,” she explains. “It has worked out well for me, because I work with ranchers from all over.”
“Producers like to use BioPRYN to cull their cattle more accurately, and bred cows aren’t sent to the salebarn accidentally,” explains Madden. “The test is also easy to do, and less physically demanding than palpation or ultrasound. It is also easier on the fetus because the uterus is not manipulated, so there is less fetal loss.”
Madden recommends producers wait until at least 28 days post-breeding to test both cows and heifers. The test also shouldn’t be given before 90 days post-calving, because residual PSPB (Pregnancy Specific Protein B) may still be in the maternal system, causing false-positive tests.
The test can also be used for recipients of an embryo transplant, however, blood is collected at 32 days of embryo age rather than 30 days. The additional time gives the embryo more time to attach, explains the lab technician.
Typically, a retest is only required when the original test needs to be rechecked, Madden continues. This could happen if a cow wasn’t a full 30 days into pregnancy when the original test was given, or if a producer suspects the cow has lost her calf.
Since the test is so accurate, producers can make key management decisions sooner. They can determine whether to cull an open cow, and they have an opportunity to market her at a higher price earlier in the year before the cattle market declines in late October. They can also choose to rebreed her.
“Cows diagnosed open can also be re-bred more quickly, resulting in tighter calving intervals, more calves born per year and higher lifetime milk production because cows achieve peak milk more often,” explains Madden.
Producers can easily learn how to give the test themselves, Madden explains.
“It is very easy to learn to draw blood. There are videos that are available on my website, or producers can call for instructions,” she notes.
Producers can also choose a convenient time to give the test, such as during fall processing, rather than working around a veterinarian or ultrasound technician’s schedule.
However, Madden said it is important for producers to properly restrain the animal before taking blood.
“Blood can be drawn from the neck, but restraining the head can be very difficult. I recommend collecting blood from under the tail, because it is easier for the cattle and personnel,” she says.
The cow should be restrained in a squeeze chute to make drawing blood easier, with less movement from the cow.
To collect blood from under the tail, Madden says the tail should be cleaned, if fecal matter is present, to prevent contamination.
“Contamination is best avoided by always using a new needle for each cow to reduce any false positives,” she says. “Using blood collection needles and tubes eliminates using any syringes, and the need to transfer blood from syringe to tube.”
Madden says the test is very cost-effective compared to palpation and ultrasound.
“Palpation is running about $2.50 to five dollars per head, and ultrasound five to 18 dollars. However, that all depends on the area and number of cattle being tested,” says Madden.
The BioPRYN test costs $2.50 from Eagle Talon Enterprises, plus the additional cost of the sample tube and needle and shipping the tests.
“The test requires 27 hours from laboratory set-up to reporting,” says Madden. “A report can be made for the next working day for samples arriving in the lab before noon. The test uses enzyme-linked immunosorbent assay (ELISA) technology for processing, which contributes to its low cost and fast turn-around. If the samples are mailed by overnight carrier, add an extra day to this schedule. Results can be faxed or e-mailed back to the producer. Emailed results can be downloaded directly into most management software programs.”
BioPRYN evaluates the blood, or more specifically, the serum or plasma of cows for a protein called PSPB, says Madden.
“PSPB is produced by the placenta, and therefore pregnant animals will have the protein in their blood. This makes the test more accurate than earlier attempts at pregnancy diagnosis that evaluated blood or milk for progesterone or other hormones that can occur in normally cycling animals,” she explains.