One of the biggest environmental challenges the dairy industry faces can be traced back to mediocre reproductive performance.

If we can improve reproduction, we can lower our greenhouse-gas emissions, Frank Mitloehner, associate professor and director of the University of California-Davis Agricultural Air Quality Center, told audience members at the California Animal Nutrition conference last week.

This concept may take some time to conceive. But if fewer cows are culled due to poor reproductive performance, they will stay in the herd longer and produce more milk.  The amount of greenhouse gas produced — per pound of milk — will therefore be lower over the lifetime of these animals. Additionally, an improved reproductive efficiency would decrease the number of replacement heifers, which eat and excrete but do not produce.

“We need to intensify and improve our operational efficiencies,” says Mitloehner. “If we can improve our reproductive performance by 5 percent, we would have a bigger impact environmentally than with anything else.”

And, conventional dairying appears to be the way to go for a lower carbon footprint. Mitloehner says the carbon footprint is smaller for conventionally based systems than pasture-based systems.

“When it comes to the carbon footprint, you have to look at it on a per-unit-of-production basis,” he says. The conventional system comes out on top. A cow in a conventional system produces 450 grams of methane vs. 800 grams from two cows in a pasture-based system to reach the same production. This is mostly due to differences in roughage and efficiencies.