Pregnancy Diagnosis: Fall is the time for cattle producers to consider options for pregnancy diagnosis

Chilly morning temperatures and an array of golden hues mark the beginning of fall and the end of summer grazing. Around this time, producers start to gather their cows off of summer range or mountain forests and trail them to meadows at lower elevations. 

As they enter this next phase of the production cycle, beef cattle experts remind producers of the benefits of pregnancy diagnosis, as well as available options. 

Benefits of pregnancy diagnosis

University of Nebraska-Lincoln (UNL) Beef Cattle Reproductive Physiologist Rick Funston notes, although research has shown diagnosing pregnancies in cattle herds ultimately adds to a producer’s bottom line, it is “grossly underutilized” with only 20 percent of producers employing some kind of pregnancy diagnosis at the time his article was published in 2020.

The most prominent benefit of pregnancy diagnosis is identifying non-pregnant cows before winter months when producers have to feed hay. 

With high input costs driving up the price of feed and drought leaving some producers in a shortage, getting rid of open cows may be necessary to save on labor, money and resources.

In an August 2024 North Dakota State University (NDSU) Extension and Ag Research News article, NDSU Extension Livestock Management Specialist Lacey Quail reiterates this sentiment, stating, “Cattle producers have or will soon be removing bulls from their spring-calving herds, bookending another breeding season, and will need to identify which cows will calve next year before winter feed resources are allocated.”

Additionally, UNL Extension Educator Aaron Berger notes open heifers, cows and bred cull cows can provide as much as 20 percent of the gross income to a cow/calf operation annually.

“Taking advantage of opportunities to effectively add value to and market these heifers and cows using timely pregnancy diagnosis and an understanding of market seasonality can allow producers to capture more profit from this segment of the cow/calf operation,” he explains in an Aug. 20 UNL press release.

Pregnancy detection methods 

Producers who choose to employ pregnancy diagnosis in their herds this fall have three strong options – palpation, ultrasound and blood testing.

Rectal palpation is the most widely used, “tried-and-true” method for detecting pregnancy in cattle.

According to Berger, an experienced technician can identify a pregnancy as early as 35 to 50 days after breeding and can give an accurate estimate of age of the pregnancy out to 120 days after breeding using palpation.

“Ultrasound has been utilized for decades and is the most informative of the methods available,” Berger says. “Ultrasound can identify a pregnancy as early as 28 days post breeding.”

He notes experienced technicians who use his method are able to accurately age pregnancies in the first trimester and identify the sex of calves 55 to 110 days after breeding. 

Last but not least, blood tests are able to detect pregnancies through the presence of associated glycoproteins. Berger points out this method must be used at least 25 days post breeding in heifers and 28 days in mature cows.  

“There are two different testing methods available,” Berger shares. “One requires the submission of a blood sample to a lab for analysis. The other allows for rapid results onsite within about 20 minutes of the blood sample being placed in the testing kit. Cows which have calved need at least 75 days post calving to use the blood test method, or false positives may result.”  

Factors to consider

Experts across the board agree producers should compare these pregnancy detection options to determine the best fit for their herd management program.

More specifically, Quail encourages producers to consider four factors – cost, timing, required training and completeness – when weighing the pros and cons of each method.

Quail notes cost is the first consideration for many producers when deciding the best way to diagnose pregnancy in their herds, and she recommends analyzing the cost of the method alongside its accuracy, result timeline and completeness. 

“For example, monitoring estrus behavior in the herd after breeding is very affordable. However, this method carries considerable opportunity cost,” she states. “Observing cattle for estrus behavior is time consuming and potentially inaccurate due to the individuality of estrous cycles and the impacts of nutrition, lactation and environment on cyclicity in cattle.”

“Additionally, with estrus detection, the result is simple – pregnant or open. This method provides no other valuable information regarding fetal age or sex,” continues Quail. “On the other hand, techniques such as transrectal palpation or ultrasound are more comprehensive, but more expensive.”

Timing is another important consideration. Quail explains specific methods may align better with certain production timelines. 

“If feed resources or cattle handling facilities are limiting factors, it is important to know when each pregnancy detection method can be performed,” Quail says. “Retaining and feeding cows is costly, and opting for earlier detection is often beneficial so open cows can be marketed earlier.”

It is also important to note stress caused by handing cattle too early in the pregnancy may result in loss.

Additionally, each method requires various levels of training and expertise.

Quail explains, “The detection of estrus and blood antigen tests both require very minimal, if any, training. They are accomplished by visual observation or simply drawing a blood sample. Both methods can be very convenient options for operations which may not have access to trained professionals.”

“As a trade-off, these methods are not as comprehensive as those requiring more extensive training,” she adds. “Ranchers should consider how the timeline and expense of these methods may fit into their management plan.”

Lastly, producers should consider the completeness of the detection method. Some operations may be able to get by simply knowing which cows are pregnant and which are not, while others may need a more complete list of information, including age and sex of the calf. 

“Every operation raising beef cattle can benefit from pregnancy diagnosis. However, the method used can vary from herd to herd,” Quail concludes. “To find the most cost-effective method for an operation, consider how soon after breeding one needs to detect pregnancy, the labor required, the availability of trained professionals and the information needed for the management system.”

Hannah Bugas is the managing editor of the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.