Picture this: Your favorite running back is headed toward the end zone. This touchdown will seal the game. Then, thinking he’s far ahead of the pack, he slows down, allowing the defensive back to cause a fumble. Argh!

Just when you think things are going well and you can ease up on cow herd management, things go awry.

Each pregnancy represents a significant investment of resources and future income, meaning protecting pregnancies is essential to herd productivity. We need to make sure we don’t fumble as we approach the goal line. Calving and monitoring the herd, practicing sound biosecurity and responding appropriately to unexpected abortions are key to protecting the pregnant cow.

After halftime

Pregnancy loss may occur soon (within 45-60 days) after conception, but many of these losses are not identified as the cow is rebred prior to the end of the breeding season.

After pregnancy testing (usually at 90-150 days of gestation), most pregnancies will progress to result in a live calf. The rate of mid- to late-term pregnancy loss is relatively low (usually less than 2%), but losses can still occur. Regular herd monitoring during this stage is important for identifying potential problems.

A multitude of factors can lead to abortions in cattle, including exposure to disease-causing pathogens and ingestion of toxic plants/forages. Many, but not all, of the processes that lead to abortion will cause cows to show clinical signs of illness. Observing appetite and attitude patterns can help identify when individual animals are behaving abnormally.

Another potential sign of abortion includes cattle exhibiting signs of estrous behavior when they should be pregnant. The occasional cow or heifer may still display some estrus-like behavior while pregnant due to hormone fluctuations, but this is rare and typically does not affect very many individuals. If you detect several animals showing heat, it may be worth pregnancy testing some of the animals to confirm.

Cattle body condition should be monitored during this period, as poor nutrition can increase environmental stress during the colder months, resulting in decreased ability to respond to disease challenges. Changes in body condition are gradual and difficult to observe when cows are monitored daily. In such cases, each day cow condition appears similar to yesterday.

However, over a period of a few months, the body score may have significantly changed. One method to monitor body condition is to take pictures of the cows every few weeks and flip through the images to help identify changes over time.

Build a defense

Biosecurity is a critical part of protecting pregnancies. Any pathogen that causes significant systemic illness in cows has the potential to cause abortion. In addition, there are specific pathogens — such as bovine viral diarrhea (BVD), infectious bovine rhinotracheitis (IBR), leptospirosis and Tritrichomonas foetus — that directly contribute to pregnancy loss.

Each of these pathogens causes different outcomes depending on the stage of gestation when the cattle were exposed. For example, T. foetus causes early embryonic loss (typically within 100 days of conception). After exposure at the time of conception, IBR may cause abortions later in the gestation period.

Vaccines are available for some of these pathogens, and working with your veterinarian to design a vaccine program for your herd is beneficial.

While a strategic immunization program is a helpful tool to prevent pregnancy loss, another tenet of protecting the pregnant cow is limiting exposure to outside cattle. Cattle are the reservoir of almost all key pathogens causing cattle abortions.

Stocker operations, commingled cattle or recently purchased animals can be sources of pathogens that threaten the pregnant herd. Maintaining separation of the pregnant cows, isolating new arrivals, avoiding unnecessary commingling and maintaining strong fences between herds reduce the chance of disease transmission.

Calling an audible

Despite our best efforts, abortions can still occur. If this happens and you identify a fetus and/or placenta in the pregnant cow pasture, contact your veterinarian. Determining whether an abortion is an isolated case or the start of a broader herd problem is rarely possible on the first case. However, saving and banking samples is cost-effective and could provide valuable information if further abortions occur.

Your veterinarian may do a necropsy on the aborted fetus and save specific samples for potential diagnostic testing. Depending on the situation, you may want to submit these samples to the laboratory for analysis. Prompt communication with the veterinary team allows for timely investigation and helps determine whether intervention is needed for the rest of the herd. Where abortions are part of a larger outbreak, early response can prevent further losses.

Postgame recap

Protecting the pregnant cow is about vigilance and preparation. Mid- to late gestation monitoring helps identify abnormal loss patterns; biosecurity limits the risk of introducing abortion-causing pathogens; and rapid response to individual abortion cases provides the best chance of identifying underlying causes. While most pregnancies result in healthy calves, careful attention to these areas ensures herd productivity and profitability are protected year after year.

Editor’s note: Author Brad White is on faculty at Kansas State University College of Veterinary Medicine and serves as director of the Beef Cattle Institute. To learn more on this and other beef herd health topics, tune in to the weekly Beef Cattle Institute Cattle Chat and Bovine Science with BCI podcasts available on iTunes, GooglePlay or directly from https://ksubci.org/.