As automated and voluntary milking systems, more commonly referred to as robots, surge in popularity, so does the interest in using such technology in a grazing-based dairy operation.
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Dairy Farmer / Freelance Writer
Brittany Olson is a dairy farmer and freelance writer from Chetek, Wisconsin. She and her husband...

Howard Straub III, manager of the Pasture Dairy Center at Michigan State University, shared his experiences and insights on managing pastures with cows in an automated milking system in a January webinar presented by Penn State Extension’s Dairy Grazing Management Guide.

The Pasture Dairy Center (PDC) at Michigan State was established in 2007 as part of a $3.5 million donation by the Kellogg Foundation to the university’s Kellogg Biological Station to build a grazing dairy research center with robots included in the design. By 2009, the PDC was milking 79 cows with two Lely robots, and 10 years later, the robots have completed 930,700 successful milkings.

“The Kellogg Foundation sometimes takes on certain functions and goals, and one of those things was originally to help small farms,” Straub said. “This is one of the things they did to [accomplish] that.”

The PDC, aside from research projects, makes most of its money from crop, meat and milk sales, a goal Straub has had all along since taking over management in 2012.


“I am trying to be as commercial as possible within the context of our research, and I think that also makes for better research,” Straub said.

Why do people graze their cows?

One of the main questions Straub gets from dairy farmers looking to either switch to a grazing-based system or graze specifically with milking robots is why they do it. Straub said an individual farmer’s view on grazing is different depending on his or her reasons for it.

Many farmers – Straub included – enjoy grazing because they feel the cows like it and the farmers feel closer to nature. The sheer sight of cows on pasture is satisfying for many. Others graze for lower feed costs and bigger profit margins, while some graziers are organic and make more money per hundredweight selling milk from cows in a grass-based system.

On the other hand, there are some who feel obligated to graze and aren’t as excited about it because they need to comply with organic regulations requiring a certain percentage of dry matter intake come from pasture. Others in this situation may need to start grazing because their milk cooperative wants them to, or a partner in the farm such as a spouse, parent or landlord wants them to.

“Some cheese co-ops want farmers to graze for more grassy notes and flavors in their cheese,” Straub said. “But what’s important is that you need to know your goals for grazing and expectations for your automated milking systems.”

How can robot dairies graze?

Straub spoke first about a system that he had first seen in action in 2010, a method he referred to as high intensity with no sort gate.

“They split the herd into two groups. One group starts in the barn, and the other group starts in the pasture,” Straub said.

Then, as cows in the first group are milked, they are released to the paddocks. When the first group is finished milking, the other group is brought to the barn to go through the robots to begin milking.

Advantages to such an approach include the fact that a lot of cows can be milked with just one robot, as well as having precise control over grazing times and milking intervals.

“The dairy I was speaking about in 2010 milked 109 cows with one robot,” Straub said.

Another system Straub used as an example is what he referred to as a single lane with a sort gate. In this system, cattle are all in one group with one or multiple milking robots. When the paddock is changed, all of the cattle are brought back to the barn for milking, and the sort gate lets eligible cows go back out to graze when they have finished milking.

With a single lane/sort gate approach, less labor is required to manage pastures and cow groups. The sort gate keeps cows in the barn until they have been milked and allows cows to have multiple passes through the pasture on their own.

“Negatives include less control over pasture quality and quantity offered, and less incentive for the cows to leave the barn as the current paddock gets stale,” Straub said. “It also involves excess walking for some cows.”

The third approach to grazing with automated milking systems Straub detailed is known as high intensity/sort gate with multiple lanes, or A-B-C grazing. The sort gate directs cows into paddock A for a set time, say 12 hours, and then to paddock B. Paddocks are divided up to allow only enough forage to graze between moves, and it gives cows incentive to return to the robots after the grass runs out.

While such a system can be labor-intensive, it gives graziers more control over precision pasture management and the usage of the sort gate to regulate cow traffic flow.

“Rarely do they have to fetch a cow for milking, and this approach can be used in high or low stocking rate situations,” Straub said.

While milking technology itself has evolved, common pasture management principles still apply to every grazing operation no matter the method of milking. Straub recommended keeping paddocks in a vegetative state to aid in milk production and palatability, and offering enough good pasture – in addition to shade and water – to keep cows incentivized to go out and graze.

“When considering new construction, place your facility in the middle of the pasture land base. This will allow for less overall travel from the barn to the pasture. Total daily walking distance will be more consistent,” Straub said. “Shade and water are readily available at all times … in the barn. Heat is an extra driver of movement in the summer, so use it to your advantage.”  end mark

Brittany Olson is a freelance writer and dairy farmer in Chetek, Wisconsin.