The genetics of feed efficiency was the central focus of the 2020 Council on Dairy Cattle Breeding (CDCB) industry meeting held via Zoom on Nov. 2. One of the latest Holstein genetic traits to be released with Dec. 1 evaluations is Feed Saved, which will aid in breeding more feed-efficient cows.
This new addition to the genomic roster is the result of collaborative data collection, methodology and research involving efforts of the University of Wisconsin – Madison, Michigan State University, Florida State University, USDA’s Animal Genomics and Improvement Laboratory (AGIL), Iowa State University and CDCB, with funding from USDA’s National Institute of Food and Agriculture and CDCB.
Several experts involved the genomic work and dairy sustainability spoke at the meeting, giving additional insight and expectations as to how this trait will perform and help reach industry goals.
Behind the trait
According to Kent Weigel of UW – Madison, selection for feed-efficient cows means those having high milk yield, low maintenance costs and a high proportion of captured energy per unit of feed consumed.
“It tells us how much energy the cow actually wasted due to being biologically inefficient by taking gross feed intake [compared] to secreted milk energy,” Weigel explained in his presentation. “There’s also energy waste due to excessive body size. If you combine those two pieces together, reliabilities tend to be higher than for residual feed intake.”
Weigel was one of the lead geneticists in the creation of Feed Saved. While the trait was designed to be relatively simple to interpret, the research and data collection is difficult to get precise, making it important to grow the reference population.
Part of the project entailed a 42-day recording period of animals between 50 to 200 days. Residual feed intake (RFI) was computed within the research station, in the experiment and from the diet of contemporary groups. The subsequent data was then passed to CDCB to be used in genomic evaluations.
In the future, the goal is to publish Feed Saved predicted transmitting abilities (PTAs) and put the trait into Lifetime Net Merit in the April 2021 revision. Reliability will be improved as time goes on, with data collection from international partners and adding approximately 750 cows into the U.S. reference population each year.
Paul VanRaden of USDA-AGIL notes Feed Saved is on a per-lactation basis. However, for the Net Merit dollar value, they are taking Productive Life into consideration.
“What we’ve been doing is multiplying by 2.8 lactation basis as an average to convert it into lifetime basis,” he says.
A sustainability solution
Sustainability, an ongoing theme in the U.S. dairy industry, is an important aspect of genetic feed efficiency. With feed being one of the largest expenses on a farm, feed efficiency has long been recognized as financially significant. However, it also has lesser-known benefits, including lessened environmental impact and helping the farm better utilize land for crop production and manure application.
Frank Mitloehner, an air quality specialist from the University of California – Davis, provided his expertise on the significance of efficiency progress in dairy cattle. While ruminants release methane into the atmosphere, a 10-year process called hydroxyl oxidation converts the gas into carbon dioxide. As part of the biogenic carbon cycle, photosynthesis occurring in the process of growing forages and other crops actually pulls carbon back out of the atmosphere.
“Genetics is the key to further improvements of our carbon footprint,” he said. “If we continue to reduce methane in the way we have been, then we will not only be viewed as less of a liability around climate change, I think we will be viewed as a solution because we can actually pull carbon out of the atmosphere by reducing methane.”
Feed efficiency is closely linked to manure output as well as methane emissions. Since 2015, California dairies alone reduced 2.2 million metric tons of greenhouse gases in their system, equating to a 25% reduction in manure methane emissions. Part of that being due to breeding more feed-efficient animals.
Lloyd Holterman, chair of the CDCB Producer Advisory Committee, explained how genetics have played an important role in sustainability at his dairy, Rosy-Lane Holsteins. Earlier this year, Rosy-Lane was a recipient of the Dairy Sustainability Award from the Innovation Center for U.S. Dairy.
“Our journey to sustainability was by improving our air and water every day and really conserving our resources to make use of them,” he said. “Our goal is to produce 1.7 pounds of energy-corrected milk for every pound of dry matter our milking herd produces. This has led us to a much healthier cow.”
Real-world applications
Creating a more feed-efficient cow can also help with the industry’s public relations effort. Many consumers have a difficult time understanding dairy cattle genetics and management. However, better practices for feeding animals can be used to make things more explainable, while building bridges based on shared values.
Juan Tricarico, vice president of sustainability research at Dairy Management Inc., believes using things like Feed Saved will be more beneficial when talking outside the industry than terms like “efficiency” or “genetic improvement.”
“For the industry to be able to talk and say, ‘I am able to save $100 per cow because I can be more efficient in use of feed’ is a great way to show sustainability from a profitability standpoint,” he said during a panel discussion. “Things such as savings have universal meanings. Consumers can understand that, and they can follow the emotion.”
There is no single silver bullet to the dairy industry’s environmental impact, Tricarico noted. While there are some tradeoffs when it comes to breeding a “greener” cow, Feed Saved is certainly a part of the solution, alongside other genetic and management tools available to dairy farmers.
