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Using pregnancy testing for drought management

Gilda V. Bryant for Progressive Cattle Published on 26 July 2022
Using an ultrasound

Most beef producers who routinely test cows and heifers confirm pregnancies when their calves are either weaned or preconditioned in late summer.

However, experts recommend checking for pregnancy much sooner, especially during a dry spell. Janna Block, North Dakota State University Extension livestock systems specialist, estimates that around 85% of North Dakota’s producers conduct pregnancy checks. “When you think about maintaining a cow, especially during a drought, feed costs are so astronomical that identifying open cows is worth the investment,” Block reports.

The three tests used to verify pregnancy are ultrasound, rectal palpation and blood tests. Block says early checking, 35 to 40 days after the end of the breeding season, using ultrasound with an experienced technician can detect a fetus reasonably early. “Some publications say [experts can test] as early as 28 days,” Block reveals. “That’s very challenging. If you look at the fetal development time line, a 30-day embryo is not even a half-inch long, and it only weighs one-hundredth of an ounce.”

A technician using ultrasound at around 55 days can provide the calf’s gender and a fairly accurate age estimate. “We can tell if that calf is A.I. or was bull bred,” Block explains. “This information helps producers group cows based on calving periods.”

A blood-based pregnancy test is another tool. The producer collects blood samples, then sends them to be tested. Operators can also use new kits designed for the veterinary practice without sending samples to be processed. Ranchers can see results in about a half-hour, similar to checking a human pregnancy test. “[Because of the time it takes to learn results], ranchers cannot immediately sort cows if they move open females out one way and pregnant cows another,” Block shares.

Rectal palpation by an experienced technician or veterinarian is typically the most economical exam, usually conducted 55 to 60 days post-breeding. They can typically estimate the age of the fetus and may also be able to detect uterine infections or other issues.

“It’s important for every producer to have a conversation with the veterinarian to learn which method works best for the operation,” Block says. “There are some regional differences [between the three pregnancy tests], but they are close in price. Ultrasound gives the operator an immediate response, the calf’s gender and estimated calving date before sorting cows.”

Knowledge is power

When ranchers know how many cows and heifers are pregnant, they can buy hay, lease additional pastures and purchase the correct number of vaccines and other supplies, saving money. When producers detect open cows, they can early wean calves and market cull cows during late spring and summer. This strategy helps ranchers avoid the seasonal dip cull cow prices bring in the fall. Culled cows and heifers may be up to 30% of a rancher’s annual income, making a significant difference to the operation’s bottom line.

Early pregnancy diagnosis gives operators more options. For instance, producers can move open cows and heifers to a fall-calving time line. That is another opportunity to use bulls. Ranchers could decide to market those females for a fall-calving program. Block says producers can find additional information about verifying pregnancies online and in agriculture publications. Along with a crucial conversation with a veterinarian, producers should consider how an early pregnancy check fits their management plans. Do operators have cows in multiple pastures they could combine with other management strategies?

“If we can recognize early that we have a wreck in a specific pasture or with a particular bull, it gives producers time to address those issues before the next breeding season,” Block concludes. “If we can identify the problem, we can correct it. Maybe those cows were a little thin going into the breeding season, and we need to boost our nutritional program next year or possibly our health program needs attention.”

Aaron Berger, beef extension educator at the University of Nebraska – Lincoln, says testing for pregnant cows is essential during drought. Open females can leave the operation sooner if feed supplies are tight. Non-pregnant heifers may enter the feeder cattle chain sooner, bringing income to the operation. Another strategy is placing females into different management groups. For instance, cows typically weigh more and are in better body condition during a drought than heifers.

“That’s your opportunity,” Berger explains. “Think about timing in marketing. When there’s a shortage of feed, identify non-pregnant animals sooner and figure out how to make that fit into your system for economic advantages. Consider marketing opportunities and what the market wants. Think about what you have. Can you make that fit the market?”

In a drought scenario, determine which cows to keep. Cows and heifers that are pregnant early deliver calves early. Heifers’ female calves born early in the calving season are older at their first breeding, which is advantageous later. “If I believe my genetics are valuable, I want to keep cows that will have heifer calves to perpetuate the herd. I’ll sell those cows carrying bull calves when I can sex those calves using ultrasound. That’s another piece of crucial information ultrasound can provide, especially for producers with genetics they believe have a lot of value.”

Berger cautions producers to be aware that early pregnancy diagnoses increase the risk of early embryonic loss when handling animals between 25 and 45 days post-breeding. The numbers hinge on the stress involved. Three to 5% loss is possible. Recognize it is a risk, so ranchers can balance that risk of some embryonic loss against the value of knowing sooner which animals are not pregnant. Minimize stress by practicing Beef Quality Assurance (BQA) guidelines for handling and transporting.

Marketing during drought

Troy Marshall, director of commercial industry relations for the American Angus Association, agrees that pregnancy checking is one of the great marketing tools, particularly in times of drought. “The earlier you get your pregnancy checks done, the longer you have to make management decisions,” Marshall explains. “Unfortunately, if you need to liquidate 10 percent of your cows, then you’re in a position to make those tough decisions.”

Marshall reports that selling open females is a difficult task in today’s market, especially during a drought. “Your best bet is to get cattle bred, if you can. Because so many people have shifted their calving season later to match up to their forage, there’s a market for later-calving cows.”

Another strategy Marshall recommends is moving open replacement females into a value-added market to upgrade the price ranchers receive. Plans such as the USDA Non-Hormone Treated Cattle (NHTC) program or All-Natural category gives producers more market access, flexibility and hopefully, more premiums for those animals.

“When operators have the chance to sex pregnancies, they can sort them into narrow calving groups, offering a calving date, adding value to those cattle,” Marshall advises. “Buyers like that, and animals are in better body condition when you sell them. When we talk about the female market, it’s always about demand, quality and condition. Selling early in a drought helps achieve all three goals.”  end mark

PHOTO: A technician using ultrasound at around 55 days can provide the calf’s gender and a fairly accurate age estimate. Photo by Paul Machant.

Gilda V. Bryant is a freelancer based in Amarillo, Texas.