by Tamara Scully

Heather Darby, agronomist with the University of Vermont, and Sarah Flack, grass-based livestock consultant, have been conducting research into the challenges and successes of 100 percent grass-based organic dairy farmers. Their ongoing research began in 2016, when the total number of 100 percent grass-fed dairy farms in the U.S. was estimated to be around 150. Today, that number has substantially increased, with over 400 dairy farms opting to feed no grain, and to rely on pasture forages – legumes, forbs and grass – to provide the nutrition a milking herd requires.

With the organic dairy sector in turmoil as surplus milk is leading processors to drop certified organic farms, adding a grass-fed certification may offer organic producers a viable option. But going 100 percent grass-fed requires a willingness to change business strategies, to focus on high-quality pasture production and grazing management beyond the requirements for organic certification, and to think differently about making milk.

Grass-fed data

There is an increasing demand from consumers seeking grass-fed milk. Grass-fed dairy is “the most rapidly growing sector of the organic milk market,” Darby said.

There’s also no overall industry standard definition of “grass-fed.” There are standards that must be met for the add-on grass-fed certification which organic dairy farmers can seek from their certifying entity. For the purposes of the research project, 100 percent grass-fed is defined as “a diet without grain in the ration. The ration is, instead, a mixture of different types of forages,” Darby said. “But no grain. That’s the key. That also includes corn silage” as well as annual forages that have grain formation.

“There are established standards now that require a third party certification,” Flack said. “The farmer is applying each year for a grass-fed dairy certification and then getting an on-farm inspection and audit. For most of the grass-fed dairy farms, this is going to be an add-on to their organic certification,” although a stand-alone grass-fed standard as well.

Organic dairies can and often do feed grain, while organic dairies seeking grass-fed certification must be grain-free, including having no grain or grain by-products in their mineral supplementation. There are limits on the amount of energy supplementation, such as from molasses, that 100 percent grass-fed organic dairies are allowed to use.

There is also an animal welfare requirement, to “make sure that the animals are doing well with this all-forage system,” Flack said.

Survey data

Researchers sent surveys to all of the 144 dairies who were identified as 100 percent grass-fed in 2016, and 83 farms responded, providing information on cow numbers, acreage, milk production, herd health and reproduction and challenges they have encountered being grain-free.

The farms had a wide range of practices. Some were seasonal, drying off the herd at the same time. Some milked twice per day, some once. Milk production and components varied widely.

“It’s hard to characterize these farms under one umbrella,” Darby said. “There is a wide range of successful production management systems.”

The average number of years as a dairy farm was 22, although the farms became certified organic an average of eight years ago, and changed to 100 percent grass-fed production just under four years ago on average. The average number of cows was 46, with some farms having over 200 cows. Production ranged from 6,000 to 10,500 pounds of milk per cow annually.

Some farms raised calves on milk for more than eight months, while other fed milk for less than three months. Some calves were bottle fed in groups or individually, while other farms raised calves with a nurse cow or on their dam. The majority weaned calves from milk at four to six months.

Almost half of the farms were raising all of their own heifers on the farm and had low cull rates. The average number of acres needed per mature cow was 5.6 on farms not purchasing any forages, which is more acres per cow than organic dairies which also feed grain. The raising of heifers “may be, in some part, contributing to the need for additional acreage per cow,” Flack said.

Common challenges found on the farms were depleted soils and a decline over time in pasture productivity, herd reproductive challenges, concerns over mineral supplementation and the increased land base and high-quality forages required to support the nutritional needs of a 100 percent grass-fed herd.

A 2016 Sustainable Agriculture Research and Education (SARE) grant resulted in the establishment of a benchmarking program for 22 survey responders who opted to enroll. This program provides participants with data regarding their own herd statistics as well as those of the other grass-fed dairies, and provides researchers with data that can help determine how best to help position 100 grass-fed dairy farms for success.

“This group of farmers has further eliminated a tool that many farmers have when the weather doesn’t cooperate,” as they are not able to feed grain and must rely on forage production, Darby said. “We want to be able to support farmers in different production systems,” although the data gained from the benchmarking program “just created more questions.”

Further grants have allowed the research to be expanded and continued.

Milk from grass

The organic grass-fed add-on standards require a minimum of 150 days on grass. On average, the farmers surveyed had 184 days on grass. The standards require that 60 percent of the dry matter intake (DMI) on average comes from pasture during the grazing season. On average, the farms had about 80 percent of the cows’ DMI coming from pasture grazing. One quarter of the farms also reported raising annual forages for harvest or grazing.

Milk urea nitrogen (MUN) values averaged 12.1mg/100ml, but the range – 3.7 to 28.6mg/100ml – showed that some farms were having problems. MUN values provide some insight into the energy/protein balance, but researchers found no correlation between the amount of energy supplementation – primarily molasses – fed and MUN values. Mineral supplementation level was a common concern of the farmers.

“Mineral deficiency can be a challenge for new grass-fed dairy herds,” Flack said, as removing grains removes the minerals they contain.

Grazing systems on successful 100 percent grass-fed farms were variable, with most being rotational systems. The average maximum days for pasture regrowth before regrazing was 36.5 in 2017 and 40.1 in 2018, while the range was from 16 to 55 days. Some farmers reported moving cows up to five times per day, while a few operated a continuous grazing system.

Getting grazing cows out of the heat and humidity is a key focus, with some farmers using shady areas with edible forages so animals can continue to graze, while others remove them from pasture and feed stored forages.

One overall concern is the depleted soil fertility and subsequent decreased yield and quality of pasture forages seen on many of the grass-fed dairies surveyed. When grain is fed, it provides minerals to pasture via manure. Adding fertility back to the soil via applications of lime, poultry manure or other organic amendments may provide a good return on investment for 100 percent grass-fed dairy farms.

Without that fertility input, “the concern is that we can’t just keep taking [nutrients], and we need to be replenishing,” Darby said. “There’s a lot more work to be done.”