Writer: Dr. Joe Paschal, 361-265-9203, firstname.lastname@example.org
According to the National Animal Health Monitoring Survey conducted by the USDA a few years ago, only about 1/6 of U.S. beef cattle producers regularly pregnancy test their cows after breeding season ends.
That is lower than the percentage reported by ranchers in south Texas in a survey we conducted several years ago.
More U.S. producers conduct a breeding soundness examination on their bulls than pregnancy test their cows, but not by much.
I still prefer to palpate my cows for pregnancy. If I know the breeding date, I feel comfortable determining 35 days of pregnancy, if I don’t, I am more comfortable at 45-60 days.
Most veterinarians who work with beef cattle are better than I am; all it takes is to be in lots and lots of cows.
However, if it is only important to know only if they are pregnant or not, all you really need to know is what an open, or non-pregnant, reproductive tract feels like. The tract of an open cow feels meaty, like the side of your cheek, and you can pick up both horns (the cow’s uterus has two medium sized horns) in your hand. They are also about the same size.
The open cow tract may be small (as in heifers) or large (as in older cows) but the feel is the same.
A bred cow, even an early bred one, has a tract that feels thin. This is because the uterine wall has expanded to contain the embryo or fetus and the fluid filled membranes surrounding it.
Palpation can also determine if the calf is alive or dead, if the cow has twins, or why she isn’t bred if the cow is open. Sometimes a fetus dies and becomes mummified or is resorbed.
In addition, having your veterinarian there gives you an extra pair of hands and eyes for other things.
The other methods of pregnancy testing are using ultrasound and blood tests (BioPRYN and IDEXX). I have used both.
Ultrasound devices are expensive but if you are doing a lot of reproductive work, and many veterinarians are, they are worth the expense. With ultrasound, you can detect pregnancy around 35 days, and you can also detect the sex of the calf and twins.
Ultrasound can detect open cows, too, and it can be used to scan the ovaries to see if there is a physiological reason for an open cow.
Usually the reproductive tract is scanned by holding the device in the rectum but there is now an extension or wand that can be used that is inserted rectally instead of using your hand.
The blood tests are similar in that they both detect a placenta-forming hormone. Usually a minimum of 2 ml of whole blood is collected in a red-top tube and is sent unrefrigerated to a laboratory (BioPryn) or veterinarian (IDEXX) for analysis. These tests are very accurate in heifers – they will only have the hormone if they are pregnant – but slightly less so in cows. This is because cows that have had calves recently may still have a little of this hormone circulating and can give a low false positive if they are still open. It is recommended that testing be done 28 days post breeding (60 days after calving) for best results.
Both tests require new syringes, needles and tubes for each cow and then they need to be shipped or taken to the laboratory. Depending on your costs, usually less than $10 per result.
So now you know. Don’t wait to discover open cows at weaning. Get them pregnancy tested so you can either get rid of them or get them bred. At the cost of about $1.50-$2 per day to run cows, spending a few dollars to detect pregnancy is inexpensive insurance.
Joe Paschal is a livestock specialist at Texas A&M AgriLife Extension in Corpus Christi. He can be contacted at 361-265-9203 or email j-paschal@ tamu.edu.
For more information regarding news from the Department of Animal Science, College of Agriculture and Life Sciences, Texas A&M University, please contact Maggie Tucker at email@example.com or (979) 845-1542.