Don Hardin

Don Hardin of Warren County, Iowa, has been involved in years of research on Maple Syrup Urine Disease, a genetic disease carried by some of his Black Hereford cattle that also affects humans.

NEW VIRGINIA, Iowa — When some of Don Hardin’s calves died nearly eight years ago, he had no idea his loss would become a child’s gain.

All Hardin knew was that he had dead calves, and he wanted to know why.

“It was frustrating,” he says. “You expected some loss, but not this.”

Hardin says he noticed a difference in the dead calves. He says the dead Black Hereford calves had minor differences in their eyes and coat than the Shorthorn calves.

After 23 to 36 hours, the affected calves could not stand, developed unfocused and cloudy eyes, and were unable to nurse. Not long after, the calf would die.

After years of testing, Hardin learned some of his cattle were carriers for Maple Syrup Urine Disease (MSUD), a disease that affects the liver. And he learned humans also contract MSUD.

A self-proclaimed “city boy” who says he was bit by the cattle production bug as he approached 40, Hardin started out with a few head of Shorthorns. In December 2009, the Warren County producer purchased six Black Hereford cows and one bull he named 8-Ball.

“I did that because my son liked the black cattle with the white faces, and I wanted to keep him interested,” Hardin says.

In the bull’s first calving season, there were death losses. The next year, in 2012, Hardin used artificial insemination, reserving the bull for clean-up work.

Exploring genetics

Hardin, who works full-time as a CPA for the Iowa Farm Bureau, eventually split the AI calves from the other calves, and realized the death rate was about 25%.

“We knew at that point that we had an issue with genetics,” he says.

He sold 8-Ball in 2014, but still did not realize he was an MSUD carrier. Semen purchased from another bull also carried MSUD, unbeknown to Hardin.

Hardin’s path eventually took him to Don Coover, a geneticist from Kansas. Coover suggested he speak with Jon Beever, a geneticist at the University of Illinois.

He sent one ear from a calf along with ear notches from the parents to Beever, who eventually diagnosed MSUD in June 2016.

“It was bad news, but it was also a relief to find out what it was,” Hardin says.

Blood samples from the Black Herefords showed 21 of 43 head were MSUD carriers, Hardin says.

“That year it was painful to send several good bull candidates to the feedlot,” he says. “Culling decisions on bulls would be more stringent than the cows.”

Expanding the diagnosis

In the meantime, Hardin had successfully managed the issue, with death losses shrinking drastically. Eighteen months later, he heard from Beever.

“He said a children’s clinic in Pennsylvania was treating children with MSUD,” Hardin says, and they were looking for cows to test a possible cure.

“Days later, Dr. Beever connected me with Dr. Kevin Strauss, the medical director for the Clinic for Special Children in Strasburg, Pennsylvania. I learned that he had been studying MSUD for almost 20 years.”

At the time, Strauss told Hardin that children with MSUD survive on a special protein-free diet. Researchers had developed a remedy that needed to be tested on cattle before possible use with humans.

A team from the clinic traveled to Iowa and tested all 143 cattle on the farm. Researchers told Hardin the effects of MSUD on cattle and humans were quite similar.

“It was a day to remember, and the hope of helping MSUD children was exciting,” he says. “The concern for MSUD cattle became secondary to thinking about the possibility of finding a cure for these kids.”

None of the Shorthorn cattle tested positive for MSUD, Hardin says. But eventually, MSUD testing would become a requirement for the certified sire programs of both the American Black Hereford Association and the American Hereford Association, Hardin says.

And, there is good news on the human side.

“On Oct. 18, Dr. Strauss reported the protocol has been approved for dosing the calves and they have enough gene replacement vector to treat four calves,” Hardin says. “The time to implant 10 homozygous MSUD embryos is close. A comprehensive MSUD historical paper is almost ready for submission and will encompass information about both bovine and human gene replacement studies. This is exciting, and the Black Herefords are part of this story.”

Hardin adds while he would not wish his journey on anyone, it has made him a better cattle producer.

“I’m glad it’s behind us, and I’m glad the pain we went through is able to help some other people,” he says.

“And I would tell people that if you do have a genetic issue, don’t panic. Develop a game plan. You don’t need to have a gene sale and start over.”

Sign up for our weekly CropWatch newsletter

* I understand and agree that registration on or use of this site constitutes agreement to its user agreement and privacy policy.

Jeff DeYoung is livestock editor for Iowa Farmer Today, Missouri Farmer Today and Illinois Farmer Today.