Swine geneticist and pig genome map facilitator.
Max Rothschild, widely recognized as an international leader in pig genetics, has vivid childhood memories of two favorite things — fishing and pigs. He distinctly remembers going with his father and twin brother to visit a farm in Indiana where they would walk among the sows, kicking around the corn cobs to reveal nice fat worms for fishing. With an ample supply of bait, he and his brother would grab their cane poles and head to a nearby creek. He was just 4 years old.
“That was my first experience with fishing and my first experience with pigs. I loved it,” Rothschild remembers fondly. Well over 50 years later, his passion for both remains.
Shortly after that early childhood experience, the Rothschild family moved to Los Angeles. To cultivate the twins’ interest in animals, his father bought them a pair of guinea pigs. “Ostensibly, I think he bought them to teach us about sex, because there was a male and a female,” he says. “But I was more interested in the coat color patterns that we got from the matings.”
As he entered his teen years, Rothschild was soon distracted by the opportunities for surfing and body surfing on the southern California beaches. Those summers were also spent working with a local veterinarian, stirring his first thoughts about pursuing the profession.
Like many families who trace their roots to family members who immigrated, Rothschild’s parents — his father a chemist, his mother a librarian — were strong advocates of education. They assured their twin sons and a daughter that tuition and room and board would be covered, but if they wanted spending money, they were expected to get a job.
Interest in Pigs Returns
“I didn’t see another pig until I went to college (University of California –Davis), but there was that little seed in the back of my head about pigs,” Rothschild explains. “Every day I would walk from my dormitory to classes, passing the university’s pig farm. One day, I literally jumped the fence and ran into the farm manager, Jim Moore. ‘Got any jobs?’ I asked. He said, ‘Sure, you can start by shoveling pig manure, then I will teach you something about pigs.’”
Through the next 3½ years, Rothschild says he learned a lot about himself and about pigs from Moore and the small herd of purebred Durocs. “I’m a type A personality, and I know I need to slow down at times,” he admits. “Working with animals, I think you can learn a lot about how to observe things. The best livestock people are those who take the time to try to see what the animals are telling them.
“I think the biggest thing I learned from pigs is to be careful about making judgments based on just a few numbers. There is a lot of variation out there, and you have to be a good observer of it. In everyday pig production, much attention is given to establishing good mean performance — and that requires fairly large samples.
“And there’s got to be some balance. Even though a project may be focused on reproduction, we also need to think about how it affects other traits and total production,” he continues.
“Nature created animals that are relatively plastic; that’s especially true about pigs. It is pretty easy to change the phenotype of pigs, but we really need to ask ourselves: ‘Are we changing the overall good of the pig or just one trait?’ That is something I have been more interested in as we’ve gotten more involved with thinking about the new techniques of identifying single genes, as well as understanding the multiple effects,” he concludes.
Rothschild continued to weigh his interest in genetics against the goal of becoming a veterinarian. During his junior and senior years, he took several animal breeding courses. “I liked animals, but I always liked genetics more,” he explains.
As his undergraduate career drew to a close in 1974, his student advisor, Eric Bradford, challenged his pending decision to accept a job offer from Foster Farms, a large broiler producer in California. Bradford knew a graduate student slot was open at the University of Wisconsin-Madison and he encouraged Rothschild to apply. “You can study genetics, which you are obviously good at and you like, and they want you,” Bradford encouraged.
Just a few days prior to the deadline for accepting the Foster Farms’ position, Rothschild and his soon-to-be wife, Denise, agreed the move to Wisconsin was a better fit. Under the guidance of A.B. Chapman, he worked with pig genetics and attained his master’s degree in 1975.
His next move took him to Cornell University. “I took a hiatus from pigs and pretty much focused on dairy cattle for 6-7 years,” he notes. A Ph.D. degree was earned in 1978, and Rothschild applied for dairy cattle breeding positions at the University of Maryland and a statistics position at North Carolina State University. The Maryland position got the nod, but an unexpected call from Gene Freeman about an animal breeding position at Iowa State University gave him reason for pause.
The dairy department was small and Rothschild soon felt bored. “I was bored in the sense that a cow has just one calf each year and she doesn’t have her first calf until she’s 3 years old. Generation intervals are long, offspring numbers are short. You can’t do much genetic work with that,” he explains.
“Pigs, on the other hand, have at least two litters per year and they have lots of piglets — perfect for genetic experiments,” he adds.
As luck would have it, the ISU position opened up again, and Rothschild was ready for the new challenge. He increasingly found more opportunities working with individual swine genes. This position paired him with swine geneticist Lauren Christian, who would become “pivotal” in Rothschild’s career.
The move also set in motion an unintentional trend in which he would devote seven-year blocks of time and effort in a specific swine genetics discipline.
“The first 7-8 years were spent on a selection experiment for leg soundness in pigs,” he notes. “It became a classic experiment and was incredibly successful. The correlated responses on backfat and growth were irrefutable.”
The next seven-year stretch surfaced in 1985, when Rothschild met Carol Warner, who was working with disease resistance in mice. “She convinced me that I should look at the same complex in pigs — which was a brand-new area,” he explains. “I gave a talk to a group of long-time animal breeders, and they told me I was crazy. ‘You don’t know a damn thing about what you are doing,’ they chastised. I said, ‘You’re right, I don’t have a clue about what I’m doing, but I’m going to get started anyway.”
From 1985 to 1993, Rothschild and his colleagues began to identify the associated effects, the major histocompatibility complex (MHC), a large genomic region or gene family that encodes MHC molecules that play an important role in the immune system. “In that complex of genes, on chromosome 7 in the pig, there are a bunch of other genes for immune response, indirectly related to growth rate,” he explains.
From 1993 to 2000, Rothschild’s focus was on mapping the pig genome, with the primary goal of identifying individual gene effects. He has served as coordinator for the USDA’s Pig Genome Mapping Project since 1993.
Rothschild feels genome mapping, and now sequencing, efforts will discover more about what individual genes do and how they interact.
New gene-association work by the USDA’s research consortium targeting porcine reproductive and respiratory syndrome (PRRS), led by Joan Lunney, potentially could have a huge payoff. “When we have disease in animals, we always think about three ways to stop it — prevention, which we haven’t done very well with PRRS; vaccination, which we likewise haven’t done very well with PRRS; and disease resistance, which I actually think we are making some headway with as it pertains to PRRS,” Rothschild states.
“I don’t think we will eliminate the disease, but we hope to create a pig that can grow faster and be more immune to the negative effects of the disease. We will probably have to live with the disease until somebody comes up with an effective vaccine.
“Mother Nature is pretty good at throwing us curve balls,” he continues. “Our goal as geneticists or vaccine-makers is to try to keep up as much as possible. I think we will develop genetic solutions that pertain to animals that will withstand stresses of all kinds, which will improve animal welfare because the pigs will have higher general and specific immunity.”
Sequencing the Pig Genome
The first draft of the pig genome was completed in 2009 by a team of scientists around the world. The unraveling of DNA to understand the genetic code has helped identify specific genes associated with key performance measures in pork production, Rothschild explains. For example, the IGF2 and MC4R genes are known to affect pig performance and leanness; CAST and PRKAG3 genes affect meat quality; and ESR and PRLR genes impact swine reproduction.
“We’re still working on the annotation, which describes what each gene is. Using the human genome (announced 10 years ago) as a parallel, we are still in the early phases of genomic medicine. With the pig genome, I think we are headed toward a more advanced understanding of pigs genetically, a better understanding of feed efficiency and growth rate physiology and more welfare consciousness. The more we understand about the pig as a biological system and its genetic underpinnings, the more likely producers will be able to produce pigs as humanely, carefully and effectively as possible. That is every producer’s goal, and it is our responsibility as scientists to make that science applicable,” he says.
Mentors and Mentoring
Rothschild is quick to credit his parents for his pragmatic approach to life and his career. “My mother, because she really pushed education; my dad, a scientist/chemist, because he always stressed: ‘You’ve got to be prepared for things.’ He liked to quote Louis Pasteur’s sage advice: ‘Chance favors the prepared mind.’”
Other influential mentors include A.B. Chapman, “because he was a biologist more than he was a geneticist;” C.R. Henderson, “because he was a statistician;” and Lauren Christian, “because he encouraged me to go to the farm; he was a livestock person, as well as a geneticist, and he taught me to think beyond the statistics beyond the genetics, and to ask how those things fit with the animals. That was crucial. I learned as much from Lauren by observing him with people as I did from listening to him,” he reflects.
Rothschild’s advice to today’s students: “First, don’t be set in what career path you will take; you’ll likely change careers every 5-10 years. Second, you’ve got to read, and think through what you have read. Third, anyone interested in agriculture has to be science-based. We need people who are well-trained in math and the sciences. Finally, I tell them to dream. There’s a big world out there.”
Feeding the World
During the idealistic ’70s, Rothschild joined others in the rallying cry to feed the world. “Forty years later, we haven’t been as successful as we wanted,” he admits. While he stresses how thoroughly he has enjoyed the various phases of his work with genetics across four decades, he asks himself: “Is there something else I could do?”
The answer came through an Iowa State-led initiative called the Center for Sustainable Rural Livelihood, which helps train people in Uganda about livestock production — mostly pigs, chickens and goats — to help them be more food-secure.
“I’m having a great time,” he says enthusiastically. “I’ve been working in Africa and Uganda for the last five years. I go back once or twice a year to help train people and build facilities. I can see the people I have helped — the poor kids with the distended bellies caused by poor nutrition. When I go back, they may have fours sows instead of two; the kids look healthier, even though they may still be in tatters.”
Recently, Rothschild was accepted into the Jefferson Science Fellowship, a program sponsored by the National Academy of Sciences (NAS), where senior scientists are placed with the U.S. State Department or USAID in Washington, DC, to provide a science background for economic development programs in poor countries. He is one of 13 recipients selected from nearly 100 applicants for the year-long appointment, set to begin in August.
“I am really excited because it fits with my general interest to get more involved and help address the general food problem in the world. The goal is to bring science to policy,” he says.
Plans for after the sabbatical? “I’ve been blessed with great jobs; Iowa State is an outstanding place to work. I see me doing less molecular genetics, looking more at the global use of technologies to feed people. That’s where I want to end up in my career,” he says.
And, if you decide to drop by Kildee Hall on the ISU campus on a pleasant summer afternoon, don’t be too surprised if on his office door you see this scribbled note: “Gone fishin’.”