YOU CAN COUNT ON IT: Genex launches new evaluation to help producers determine a bull’s fertility |

YOU CAN COUNT ON IT: Genex launches new evaluation to help producers determine a bull’s fertility

Carrie Stadheim, Editor
Producers will be able to count on an AI bull a little more in the future than they have up until now. New research by Genex will help determine the fertility of donor bulls. Photo by Chesna Smith


It is perhaps the most-dreaded four-letter word in the language of ranching.

Ranking right up there with bull sale day and shipping day, the day a rancher pregnancy tests can be one of the year’s most stressful.

A ranch’s entire profit potential relies on the ability of the cows to produce and raise a calf, then come back into heat and get pregnant again in a short period of time.

It seems simple but any rancher can tell of the various interferences that wreak havoc on this cycle.

When pronounced open by the vet or ultrasound technician, often the cow is blamed. “She was thin. She had trouble calving. Maybe she’s racist and she didn’t like that bull.”

When cows were bred using artificial insemination, the list of possible alibis becomes even longer. “The weather was bad that day. I think she slipped on the ice. The help was loud and spooked the cattle. I think we got a bad batch of semen. The technician was inexperienced…” The list could be endless.

But how many times do we blame the fertility of the bull?

Associate Vice President of Beef Programs with Genex Cooperative, Inc., Willie Altenburg said we might want to think about doing it a little more often.

Blaming the bull, that is. Or maybe thanking him, depending on the individual.

In fact Genex recently developed a research program to determine just how much blame or credit the bull should take.

“Genex is pleased to launch PregCheck, the first sire fertility evaluation in the beef industry,” said Brad Johnson, the company’s Beef Product Development Manager.

“Genex has put a lot of effort in the last 12 to 18 months to gather fertility data on the main bulls in the industry,” Altenburg explained.

The semen of two different bulls may look very similar under the microscope, yet perform very differently when used in cows. Rather than basing fertilty predictions on what we can see in a slide, why not let the cows tell us which bull’s semen is most fertile? That’s what PregCheck does, the Genex news release said.

Altenburg said the company has evaluated an initial group of Simmental and Angus bulls, using 500-600 straws of semen for each bull they are testing. The study can be done in a fairly short amount of time, as they can ultrasound or palpate for pregnancy within 90 days of insemination.

A fertility score is given to those bulls that pass, and 100 is considered average. “A bull with a score of 103 is six percent better than a bull that’s 97. So you can expect a 6 percent increase over a 97 bull,” he explained.

Altenburg said a customer might be worried about a bull with a score of 97 but he would remind them that up until now they have used bulls with unknown fertility. “The bull they have been using might have been an 80. A 97 would be a lot better than that,” he explained.

Aaron Strommen, a Fort Rice, North Dakota, Angus breeder, said he will be paying attention to fertility scores on AI sires. He might not base his breeding decisions on the scores, but he’ll take them into consideration.

“The data that they are collecting, I think it’s really valuable. That information really matters to the commercial guys. It is important,” he said.

Strommen expects that commercial producers who breed large numbers of heifers will be some of the most significant beneficiaries of the data. Because Strommen Angus uses natural heat detection rather than heat synchronization, they don’t see as much fluctuation in breeding success from bull to bull. But the commercial cattlemen who utilize timed breeding, inseminating a hundred or more heifers with one or two bulls, will likely want to seriously consider the fertility level of the semen on the bulls, he believes.

Like with any other breeding data, in-herd management will determine the exact statistics, or pregnancy rate in each case. Altenburg compared it to a weaning weight EPD, where one herd usually averages a weaning weight of 550 pounds, whereas another herd averages a weaning weight of 450 pounds. A bull with a weaning weight EPD of 70 won’t add the exact same number of pounds to both herds, but it will affect them on a percent basis. The same can be expected for PregCheck data. No bull can be guaranteed to breed 100 percent of cows in any scenario, he said.

Altenburg stresses the point that PregCheck is not an Expected Progeny Difference or EPD. “This is not a prediction of the fertility of his progeny; it is a prediction of the individual sire’s frozen semen fertility,” Altenburg said. He also explained that traditional semen testing may or may not jibe with PregCheck. A bull might test successfully in the traditional lab situation, and he is likely fertile for natural use. But that same bull might have semen that doesn’t result in as many pregnant cows as they would like in an AI situation.

Bulls should be two years old before being tested in this capacity, Altenburg believes.

“There seems to be a necessary maturity pattern to bulls that they should be two years old before you can measure their true fertility,” he said. Younger bulls can produce inaccurate or unpredictable results, he said.

Some of the company’s and their clients’ favorite bulls “proved up” in the test, Altenburg said. “Some of the old standbys, like ‘Thunder,’ he’s been around for ten years. Our representatives have said that he’s a good, fertile bull. And he turned out to be just that.”

The bulls that did not meet Genex’s standards were culled from their offering.

Genex plans to continue testing their bull battery, Altenburg said.

Altenburg said that Dave Patterson, University of Missouri, “planted this seed several years ago,” and that the studies are mirrored after those done in the dairy industry.

Patterson supports Genex’s efforts.

“It was really needed by the beef industry because we were seeing significant increase in interest in synchronized AI,” he said.

Patterson said in one timed breeding research project he oversaw several years ago, all other things equal, one well-known sire settled cows at 78 percent while another produced only 28 percent bred cows. Strengthening the U.S. cow herd through genetics will be important for our nation to successfully compete in the global marketplace, he said. And Patterson believes that simple, inexpensive and successful AI synchronization will be a key to achieving this goal.

“I applaud Genex for jumping into the middle of it,” Patterson said.

“We couldn’t wait to release this information. It’s been very well received by the industry,” Altenburg said.

A list of the available genetics, with PregCheck data on the Angus and Simmental bulls, is available at