But Mosbacher said the U.S. Labor Department was misguided in its attempts to protect children from farm accidents and he's relieved the agency dropped its plans this spring and has promised not to take up the matter again.
"You can't make a rule to stop every accident," Mosbacher said after his son Jacob hopped off the 40-year-old, 60-horsepower tractor at their farm near the tiny southern Illinois town of Fults. "There's always a risk in life, no matter what you do."
Labour Department officials don't deny that, but they note that children performing farm work are four times more likely to be killed than those employed in all other industries combined.
Under the Labor Department's failed proposal, paid farm workers would have to be 16 to use power equipment, such as tractors. They would have to be 18 to work at grain elevators, silos and feedlots. The rules would not have applied to children working at farms owned by their parents, but they would have limited the paid jobs youngsters could do on their neighbours' and relatives' farms.
John Myers, chief of the National Institute for Occupational Safety and Health Administration's surveillance and field investigations branch, said it's unfortunate the agency dropped its proposal in the face of intense opposition from agricultural groups. Agency officials have said they will not take up the matter again as long as Barack Obama is president.
"I have not seen any youth working in other industries that are at higher risk," Myers said. "(Farming) may be an accepted risk for the parent, but the question is to put that risk on the child. That's the question that's not being adequately addressed.
"If society says you have to be 16 to operate a car, I don't see how you can say it's any less sound advice that you have to be 16 to operate farm equipment," he added. "I suspect this will not be addressed again, and I suspect we will continue to have youths dying on farms each year in situations that were perfectly preventable."
The lack of action also troubles Cheryl Monen, who lives in the small northwestern Iowa community of Lester.
Had such child labour rules been in place a year ago, her 17-year-old son might still be alive.
Jordan Monen was into his second summer working on a cattle farm in July 2011 when he climbed into the bucket of a payloader and was hoisted up to fix the top railing on a cattle shed's sliding door. The machine lunged forward and smashed the teen's face between the railing and the back of the bucket. He then hit a cement feed trough as he tumbled to the ground.
The boy was taken to a hospital, where he was declared dead of severe head trauma.
A year later, his mother remains haunted about her decision to let her son take the job.
"I feel so guilty about it now. I just had not put it together how terribly dangerous it was and the risks he was in," Monen said. "I really struggle with that. Now, I really wish I never suggested he get a job."
Monen now thinks anyone younger than 18 should be barred from working on a farm "because they don't recognize the dangers." She also said children shouldn't be allowed to work on farms and ranches not owned by their parents.
"If they wanna have their own kids in there, go for it," she said.
The push for tougher restrictions came at a time when fewer children are being injured on farms.
For every 1,000 U.S. farms, agriculture-related injuries to workers younger than 20 dropped by nearly half from 2001 to 2009, from 13.5 injuries to 7.2 injuries, according U.S. government figures. Injuries were most common among children ages 10 to 15, but they also dropped by nearly half during that period.
Farming groups attribute such declines to farmers' and ranchers' greater awareness of risks, but they add that it's vital children begin farm work at an early age so safety requirements become engrained in them. Agriculture groups also note that rural children looking for summer jobs often have no option other than farm work and enhancing regulations could dampen kids' enthusiasm for becoming farmers.
"We're the first to recognize that farming can be dangerous, but broad, sweeping intervention is not the best way to go about addressing it," said Kristi Boswell, the congressional relations chief for the American Farm Bureau Federation, which opposed the Labor Department's push.
Debbie Mosbacher said the proposed federal rules didn't reflect the reality on farms, where children grow up understanding the dangers and are eased into risky chores.
She noted that for Jacob, that meant riding on the tractor in his father's lap when he was 4 and feeding livestock when the cattle still towered over him. Last year, he started driving the riding lawnmower.
When it comes to farm kids pitching in, "a lot of times, yes, it's a necessity," she said. "A 10-year-old may not be able to load a 70-pound bale. But everyone's got a job to do, and if you wait until they're 18 to teach them it won't be something that's instinctive in them."