When Francisco Peñagaricano MS’14, PhD’14 reflects on what first drew him to the study of genetics, he thinks of Mendel’s Laws of Inheritance. He remembers being fascinated by the ways in which the alleles of two gametes sorted neatly into genotypes in a grid, revealing the phenotypic possibilities.
As an associate professor of quantitative genomics in the Department of Animal and Dairy Sciences in the UW’s College of Agricultural and Life Sciences, Peñagaricano seems to have inherited that neat, categorized quality himself as he summarizes the questions his lab seeks to answer and the implications of those answers on the dairy industry.
In the Peñagaricano Lab, students work to understand the genetic architecture of cows’ economically relevant traits: those that prove beneficial to a profitable dairy. These traits include feed efficiency — producing the same amount of milk on a smaller amount of feed — reduced methane emissions from bovine belching, and resilience.
But what does all of this have to do with the price of milk? According to Peñagaricano, just about everything.
“Our goal is to address the concern of the society, and without [question], this society is very concerned about dairy farming,” he says, “about the impact that dairy farming has on climate change and global warming, the impact that dairy farming has on soil and water quality, the impact that dairy farming has on animal welfare, [and] the use of pharmacological interventions and impact on food safety.”
Through a study funded by the Greener Cattle Initiative, Peñagaricano and his lab are partnering with three other land-grant universities, the USDA, and the Center for Dairy Cattle Breeding to address these concerns by developing genetic and management tools for mitigating methane emissions in dairy cows. Presently, no tools exist with which dairy farmers can identify, select, and breed dairy cows for lower methane emissions, but there are certainly incentives for doing so: in addition to reducing the amount of the greenhouse gas emitted by the dairy industry, such a tool would allow for selective breeding of a more energy-efficient and cost-effective cow.
“You can think about the production of this gas [in the rumen] as a loss of energy … that could end up in more milk production or more growth,” Peñagaricano says. “That means if you reduce methane emissions, that energy probably will be captured by the animal in a different, more productive way.”
The Peñagaricano Lab collects data on feed intake and methane emissions at the Arlington and Marshfield Agricultural Research Stations using GreenFeed systems. These systems use alfalfa pellets to incentivize a cow to visit, then vacuum the air during the visit to measure methane output. They also measure body weight to track productivity and feed efficiency.
The project team also hopes to build their predictive tool for methane emissions based on an existing, routine process in dairy farming: milk testing. American farmers are required to test each cow’s milk once a month for levels of fat, protein, lactose, and somatic cell counts; Peñagaricano hopes to correlate this data to a cow’s methane production.
Another phenotypic (related to observable traits) approach the lab has taken to predicting methane production is to better understand the function and composition of the rumen, the stomach compartment in which methane is produced. To avoid the invasive sampling of the rumen itself, Peñagaricano’s lab has explored alternative methods of studying it via samples of related and more accessible microbiomes.
The team is only a year and a half into their study, but their data are already promising: they have been able to confirm the heritability of methane-emission traits — which are “at least as heritable as milk production, or even more” — indicating that methane-emission can be addressed through selective breeding.
As for using milk testing to predict methane production, the team has recorded strong correlations between their predictions and observations, suggesting the viability of this method going forward and in developing predictive tools. Finally, in the nearly 700 fecal samples they’ve analyzed, the team has recorded strong correlations between methane production and organisms present in the fecal samples, confirming the suitability of fecal samples as proxies of the rumen microbiome.
Do these early results point to a methane-free future of bovine belches? Unlikely, Peñagaricano says. But eradication was never the goal. Like everything from lightbulbs to phone batteries, the future of dairy lies in its efficiency.
“The cow today probably is more efficient than the cow of 50 years ago, because the cow today [is] eating more, but not twice as much … [and] she's producing more than twice,” Peñagaricano says. “But [there] is still room for a lot of improvement.”
