Oh no, she’s open!
Once in a while, you hear through the grapevine that someone’s cow herd had an unusually high number of open cows. Recently, I learned of a new producer with 100 percent open herd, which is not hard to do when they only own one cow. Hurts just the same when you have any open cows. Some clues may help you identify why your herd has a high number of open cows.
If all the open cows are from one pasture, it’s easy to blame on the bull. Perhaps there was some foot rot, pinkeye or another bull visiting. A bull could be temporarily infertile due to illness or injury and then fine again by the time open cows are identified. With your vet, review your routine vaccinations, actual products and timing. Records of when the vaccinations were given will be good information to share.
While there can be a number of infectious causes of pregnancy loss, there are a few diseases that cause loss of pregnancy early in gestation. Those would include Trichomoniasis, Camplyobacteriosis, Neosporosis and Leptospirosis. Your vet will know about the incidence of these problems in area herds, and can tap into resources of the K-State Veterinary Diagnostic lab as needed.
Various stressors such as nutritional change, predators or extreme heat can cause embryonic loss or reduced conception rate. Because animals are adaptable and vary in their tolerance to stress, it may be difficult to assign one of these stressors as the cause of pregnancy loss.
Less than adequate nutrition is the most common cause of reduced pregnancy rates in cow herds. Body condition scores at the beginning of breeding season may be a clue. If open cows have low body condition scores at pregnancy checking time, review your nutrition program pre-calving and post-calving. It is very difficult to get a thin, young cow to rebreed.
I’ve been using a computer program called Beef Ration and Nutrition Decision Software (BRANDS). With BRANDS, you can look at your rations and determine if there is a deficiency, or if there’s a more economical way of feeding to meet your cow herd’s nutritional demands.