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The on-farm practicalities of grass-fed milk

Tamara Scully for Progressive Dairy Published on 11 September 2019
Cows in pasture

One hundred percent grass-fed milk is a relatively new – or at least re-emerging – focus for dairy farmers in the U.S. Unlike certified organic dairy practices, no grain is allowed to be fed, so these cows make milk from pasture alone.

With costly certified organic grain prices, more organic dairy farmers are eliminating grains and making the move to all-forage dairying, Fay Benson, New York dairy specialist, said during the 2019 Northeast Pasture Consortium.



“It’s really been a gift, this grass-fed market,” Benson said. “It’s a new market that’s developed.”

Much of that development arose from concern about milk’s impact on human health. Grass-based milk has been shown in research studies to have higher concentrations of beneficial omega-3 fatty acid and heart-healthy conjugated linoleic acid (CLA) than milk from grain-fed cows.

Bradley Heins, Ph.D., associate professor of organic dairy management at the University of Minnesota West Central Research and Outreach Center, conducted a three-year study on the fatty acid profile in milk from cows fed a 100% forage-based diet in comparison with data from certified organic and conventional herds. Over 1,000 samples from the Midwest, California and the Northeast were analyzed (Grass fed cows produce healthier milk).

Heins found that 100% grass milk provides 0.05 gram of omega-3 fatty acids per 100 grams of milk while conventional levels average 0.02 gram. The highest average CLA levels in grass milk were found to be more than double those of conventional milk and almost double the amounts in certified organic milk, which requires an average of 30% of dry matter intake (DMI) from pasture during the grazing season, allowing room for grain feeding.

“Increasing the forage – mostly alfalfa and hay – in the diets and reducing concentrates will help improve the fatty acid profiles of organic herds,” Heins said. “I think the grass milk study might help conventional (dairy) nutrition in regards to higher-forage diets. We would see a really large improvement in fatty acid profiles if conventional producers that are able to graze would graze cattle.”


With the enhanced consumer focus on animal welfare, milk from the non-confined environments of a 100% grazing dairy herd is more palatable to many consumers than milk from confinement barns. Grazing dairy herds have been found to have reduced incidents of lameness, require fewer antibiotics or treatments for illness and incur fewer veterinary expenses than confined herds, Benson said.

But grass-fed dairying isn’t without its challenges.

As the amount of pasture in the cows’ diet increases, milk production does decrease. An energy imbalance occurs when grains are removed from the diet. Pasture soil degradation is a serious concern on grazing dairy farms, and keeping pasture productivity and forage quality high is imperative when making milk exclusively from forage.

To better identify and address the issues seen when implementing 100% grass-fed dairy farming, Benson led a Cornell research survey to collect monthly data from 140 grass-only farms, with 83 responding. Data from the survey showed that cows on grass-only dairies are milked once or twice per day, calving intervals are variable, a majority of farms use molasses supplementation for energy and, on average, farms had been 100% grass-fed for just under four years. The land available per cow, including both harvested and grazed land, averaged 5.5 acres.

“The cost of raising the calves on these farms is incredible,” Benson said. Most weaned calves at 4 to 6 months, although the range was from under 3 months to 8 months on milk. A small number of farms used nurse or dam cows, while the rest bottle fed, individually or in groups.

Grass-fed Monitor data

From the original respondents, 20 farms in the Northeast are participating in the Grass-fed Monitor (GFM), a monthly monitoring program. Benson shared some of the program’s findings (Benchmarks on grass-fed dairies).


The average daily production per cow was quite variable among producers, with a high of 60 pounds per cow per day and an average of 18 pounds per cow per day. The average number of cows per farm was 47, and they were grazed for an average of 184 days.

Other parameters measured in the GFM include components per cow, fat-corrected milk per cow, income over feed cost, percentage of milk check used for forage, herd cull rate, days in milk, pounds of milk per worker and pounds of milk per pound of dry matter. Data, collected over a two-year period beginning in 2016, is still being fully analyzed.

Another study, which began in fall of 2018, is gathering data from the approximately 400 grass-fed dairy farms nationwide and will provide comprehensive monthly benchmarking of 15 farms. Goals include monitoring nutrient cycling and evaluating milk urea nitrogen as an indicator of production efficiency. Soil and forage management and impacts will also be evaluated. Benchmarking sensory qualities of the milk, and understanding the consumer demand for grass milk, are also included in the objectives for this five-year USDA-ARS grazing research study.

All-grass dairying

“Frankly, moving to an all-grass dairy will depend on the profitability of the herd. I think conventional producers will be shifting to grazing to improve profitability,” Heins said. “One hundred percent grass-fed will not be for every farm. Management would be really different, even different from a grazing dairy that feeds some TMR.”

Heins calculates that the ideal amount of acreage for a 100% grazing dairy is 2 acres per cow during the grazing season plus another 2 or 3 acres per cow for harvesting winter feed. Herd size would ultimately depend upon the characteristics of the land and how many cows – producing milk exclusively on forage – it could support.

“We have taken our organic 90-cow herd to 100% grass-fed during the summer. We have chosen to do this because of economics. We have enough land to support those 90 cows for the summer grazing season, and it saves on the feed bill for the summertime,” Heins said of UMN’s dairy herd. “We get about 40 pounds of milk on grass.”

Finding markets is another missing piece of the puzzle.

“Of course, a farmer would have to have a market for the milk as well. We don’t have market for the grass-fed milk, outside of our regular organic price,” he said.

But markets for 100% grass-fed milk have been slowly developing over the past decade. Maple Hill Creamery ( was built on 100% grass-fed dairying and has grown from one farm since its 2009 establishment to over 100 farmers today. Organic Valley introduced their 100% grass-fed Grassmilk sourced from California dairies in 2011 and has now branched out to include enough farms in the Midwest and the Northeast to allow the Grassmilk brand to go local.

Making milk from grass isn’t likely to be a passing fad. More small to mid-sized confined milking herds have been finding their way to pasture grazing as dairy farmers are embracing grazing as a viable alternative to today’s conventional dairy dilemmas.  end mark

PHOTO: Grass fed dairy herd. Photo by Lynn Jaynes.

Tamara Scully, a freelance writer based in northwestern New Jersey, specializes in agricultural and food systems topics.