UW Sourced Data Allows Dairy Producers to Breed for Feed Efficiency

By Jim MasseyFreelance writer  

The feed that goes into a dairy herd accounts for more than 50 percent of the expense on an average U.S. dairy farm, so finding a way to stretch that feed while maintaining top milk production is always a high priority for the nation’s dairy producers.  

Farmers now have another tool to help them achieve that goal, thanks to a feed efficiency study being conducted at the UW-Madison and sister institutions across the country. The 10-year study provided sufficient data to allow farmers to get feed efficiency breeding values for their cows and AI stud bulls starting in December of 2020, and eight months later, “Feed Saved” was added as a trait in the widely used Net Merit Index. Farmers can save on feed costs and reduce dairy’s environmental footprint at the same time, researchers say.   

Kent Weigel, Department of Animal and Dairy Sciences chairman and professor in dairy breeding and genetics

Kent Weigel, Department of Animal and Dairy Sciences chairman and a professor in dairy breeding and genetics, was in on the ground floor of the project along with Louis Armentano, a UW-Madison dairy sciences emeritus professor, when a partnership was created with Michigan State University, Iowa State University, the University of Florida and the USDA Animal Genomics and Improvement Laboratory in Beltsville, Md. The collaborative effort has allowed researchers to gather data from multiple locations to improve the reliability of the information. 

Weigel says the dairy-feed-efficiency study wouldn’t have gained traction without genomic testing for cattle, which became commercially available in 2009. Genomic testing predicts traits that are pertinent to dairy operations such as productive life, fertility, fat, protein, milk yield and now feed efficiency.  

“Data from this study is the only way that feed efficiency could have been added as a trait within the Net Merit Index,” Weigel says. “It’s the only data that’s available.” 

“This has been a great contribution to the dairy industry,” says Francisco Peñagaricano, an assistant professor of quantitative genomics in the Animal and Dairy Sciences Department. “Now farmers can actually select for feed-efficient animals.” 

Francisco Peñagaricano, assistant professor of quantitative genomics

Genomics allows researchers to measure data on a small number of animals and use those animals as a reference population to predict values for all animals. The feed-efficiency study aggregates data from about 750 cows per year at the various research sites to determine which cows are the most profitable based on the amount they eat and how much of what they eat turns into milk. More than 6,000 cows have been studied over the length of the project. 

At the UW, about 325 cows are evaluated per year at the Dairy Cattle Center on campus and the Arlington Research Station. A sophisticated system called the Hokofarm Roughage Intake Control System is being used on most of the cows at Arlington to precisely measure how much each cow eats. 

Heather White, associate professor of nutritional physiology

“We have these special blue barrels whereby we can keep track and measure every bite the cow takes,” says Heather White, an associate professor of nutritional physiology in the UW Department of Animal and Dairy Sciences. “We measure the difference between how much we calculated she should have eaten and how much she actually eats. If she eats less than that prediction, then she is more efficient and she has a negative residual feed intake, or RFI. The practical side is if she eats less, she saved us feed.” 

Feed represents approximately 50 percent of the cost of production on most dairy farms, so if farmers can reduce that cost by maximizing feed intake and profit per cow, profits will logically increase, Peñagaricano says.  

“If you have two cows that produce the same amount of milk but one cow eats less than the other one, at the end of the day she is more profitable,” he says. “Basically the equation is always input and output. If she’s producing a lot of milk, you have to balance how much she’s producing vs. how much she’s eating. In the long term we may be pushing cows that are smaller because of this.” 

Weigel says the study has shown that it costs about 30 percent more than researchers thought to feed bigger cows.  

“Big cows are getting penalized (by the data) more than they were before,” Weigel says. “There’s a tendency for higher production to come from the bigger cows but it’s not enough to offset their greater costs. You can be a big cow, but you’d better give a lot of milk.” 

Each research site has a geneticist and a nutritionist, White notes, with the collaborative goal being to improve genetic selection for more feed-efficient animals.  

Each feeding study lasts about 45 days, using about 60 mid-lactation cows. White says one of her roles is to try to figure out what makes one cow different than another.  

“If they’re in the same pen at the same time eating the same diet and it’s the same weather and the same management, why is one cow more efficient than the other?” she asks. “Some animals, must like people, are just more efficient at using what they eat.” 

She evaluates blood metabolites and liver function and examines cows’ eating behavior – whether they eat small meals or large meals and how many times of the day they grab a bite to eat. All of the data goes into the pool of knowledge collected by the various research sites. 

Blue barrels used to track feed consumed by each cow at Arlington Research Station.

Lloyd Holterman, co-owner of Rosy Lane Holsteins near Watertown with his wife, Daphne, has been monitoring the study in his role as chairman of the Council on Dairy Cattle Breeding’s Producer Advisory Committee. The CDCB co-sponsors the research project along with the Washington, D.C.-based Foundation for Food and Agriculture Research. 

Holterman says because logic dictates that smaller cows eat less than bigger cows, the challenge moving forward genetically will be to build smaller cows that give more milk. 

“What we want is the most profitable cow, and this feeds into this whole sustainability thing,” he says. “If we have more of a moderate-sized cow, those cows will be more sustainable and have a smaller carbon footprint. 

“For the last 20 or 25 years, people who have been analyzing body condition on herds have been saying they want a strong cow that carries body condition. Now we’re saying less body condition is better. It will take time to know if we’re right. But in the long run we’re going to make progress. We’re going to be selecting the bulls that provide the genetics that make sense.” 

A research paper summarizing the project notes that the lifetime feed efficiency of dairy cows has more than doubled in the past 70 years because of increased milk production per cow, however, the fact that cows have gotten larger at the same time is counter to the goal of increasing efficiency. 

“If cows had simply gotten larger as we bred for greater milk production, this might be acceptable,” the research summary notes. “However, it seems we have bred for larger cows simply because we like larger cows and think they should produce more milk. If we want more milk, we should breed for more milk. What matters is how much milk energy a cow produces relative to her body weight.” 

Peñagaricano says it is important for the dairy industry to show society that it is doing something to reduce its carbon footprint. 

“If you need less feed to produce the same amount of milk, that means less land, less manure, less emissions and at the end of the day, it’s a win-win for everybody,” he says. “In 2022 and beyond, we have to address those concerns.” 

“Agriculture as a whole has a challenge in front of us to feed the world’s growing population with fewer and fewer people (involved in farming),” White says. “If we can make nutritious food for human consumption using fewer resources, then we can better serve the population.” 

White says the study is likely to continue long into the future because now that the feed efficiency equation is part of the Net Merit Index, if the data collection stops, it will immediately be outdated. 

“The genetics of the cows in the national herd will have surpassed the data set unless we continue to collect the data,” she says. “I think there’s a lot of value in continuing the work.” 

Weigel says the project was started with federal grants but the transition is being made to private funding through the support of the CDCB, an industry group, and the FFAR, a research foundation. 

“The CDCB is already working on what the next step will look like,” he says. “We’ll be doing this for a while, maybe another 10 or 20 years and maybe longer.”