Feeding the World Through Dairy: Genetics, Mentorship and Purpose at JER-Z-BOYZ Ranch
How genetics, trust and mentorship helped transform a California Jersey herd and influence the breed
Tim Baumgartner, genetics manager at JER-Z-BOYZ Ranch in Pixley, California, has spent his career focused on building better cows and supporting the people behind them. In a conversation with Uplevel Dairy host Peggy Coffeen, Baumgartner shared how a series of pivotal moments led him to JER-Z-BOYZ Ranch and how the herd’s genetic direction evolved into one of the most influential Jersey programs in the country.
A Jersey Herd Built on Longevity and Components
JER-Z-BOYZ Ranch was founded in 1995 by Gary and Donna de Graaf and their sons, Dustin and Daniel. Gary de Graaf’s decision to transition the dairy from Holsteins to Jerseys was unconventional at the time, but it became foundational to the herd’s success.
Today, the dairy milks nearly 5,000 Jerseys, with a focus on fertility, components and longevity. The ability of cows to last through multiple lactations has supported expansion and the sale of fresh Jersey replacements across the western United States.
Discovering Untapped Genetic Potential
Baumgartner’s relationship with JER-Z-BOYZ Ranch began while he was analyzing cows for multiple herds. During a routine visit, he discovered that several unregistered JER-Z-BOYZ cows ranked among the highest for butterfat production.
After identifying two cows with more than 100 pounds of PTA fat, Baumgartner encouraged the de Graaf family to register and score them. Once registered, those cows quickly drew attention from AI companies. “You wanted me to find you your next herd bull,” Baumgartner told Gary de Graaf. “That cow and that cow will do that.”
Rapid Industry Recognition Followed
Once the cows appeared on national index lists, interest surged. Within a short period, dozens of bulls entered AI programs, and contracts multiplied. Baumgartner described it as a snowball effect that accelerated quickly as genomics emerged and reshaped selection strategies. The herd’s genetics became known for combining flow, components and durability, helping balance the Jersey breed during a period of rapid genetic change.
Trust and Autonomy Enabled Long-Term Progress
When Baumgartner joined JER-Z-BOYZ Ranch full time in 2017, the de Graaf family gave him wide latitude to manage genetic decisions. Gary de Graaf stepped back from daily oversight, while Daniel de Graaf focused on the broader business strategy.
“That trust allowed the program to keep moving forward,” Baumgartner said, noting that freedom to experiment and adapt was essential to long-term success.
Mentorship and Feeding the World Drive His Purpose
Beyond genetics, Baumgartner emphasized mentorship as a core part of his legacy. He described guiding young people through showing, breeding and career decisions, often drawing on his own experiences growing up in Wisconsin.
“We are responsible for feeding the world,” he said, explaining how exporting embryos and genetics can improve food security globally. Helping the next generation carry that responsibility forward remains one of his greatest priorities.
Baumgartner’s work at JER-Z-BOYZ Ranch reflects how genetics, trust and mentorship can extend far beyond one herd to shape a breed and influence the future of dairy worldwide.
Hear the full conversation with Tim Baumgartner on Apple Podcasts or Spotify and watch the complete episode below.
