Milk from grass
By James D. Ritchie

For pasture-based dairy, it's measure, monitor and manage

About 50 years ago, the grand march of U.S. milking cows from pasture to pavement began. Big reasons for the migration were the seasonal swings in milk production, labor involved in moving cows from pasture to milking parlor and back again. Plus, more precise nutrition formulations, improved technology and automation of feed storage and handling made economic sense.

In recent years, some dairy herds have done an about-face, leaving concrete to go back to grass for most or all of the year. Forage-based dairies still produce only a small stream of the nation’s total milk flow, but that stream is building volume as producers adopt better forage species and more management-intensive ways to use them—especially as feed and other input costs climb in relation to milk prices.

“Input costs have gone up dramatically,” said Dr. Kent Haden, MFA vice president for livestock operations. “And costs have gone up for grazing as well as for concentrate feeds. A forage-based [dairy] system can work, but you’ll need a new mindset and a higher level of total systems management than with a more conventional operation. If you go to a pasture-based system because you’re in trouble the other way, you’re probably doomed to disappointment.”

Forage-based dairying requires a soil-plant-animal systems approach to management, Dr. Haden said. That’s especially true when it comes to cow nutrition. With grain in a bin and silage in the silo, it’s fairly simple to formulate the same ration day after day. But when growing plants supply the main feedstuff, it’s a different problem. With a grassland dairy, the goal is to provide cows with forage that is 20 percent or more protein, less than 40 percent fiber and 70 percent or more TDN (total digestible nutrients) mouthful after mouthful, and that is not such an easy task to accomplish.

“Grass quality and quantity change in a hurry,” said Stacey Hamilton, University of Missouri extension dairy specialist. “Grass is fluctuating daily; you need to be able to adapt to changing forage conditions, and do it quickly. That makes management of a pasture dairy different from a conventional dairy.”

Hamilton coordinates monthly tours of pasture-based dairies in southwest Missouri to give producers a chance to compare notes and learn from each other. He stresses the “three M” mindset of forage-based operations: measure, monitor, manage.

“Measuring both the quantity and quality of pasture re-growth is critical,” said Rich Crawford, superintendent of the University of Missouri Southwest Research Center, near Mount Vernon, Mo. “We measure each grazing paddock at least once weekly and use several techniques to measure and record the leaf stage of growth. We use that information to schedule grazing management; you cannot manage what you don’t measure. You need to know how much forage is available when you turn cows into a paddock and how much is left when you pull them out.

“Our goal is to turn cows in when a paddock reaches 2,500 pounds of grass per acre and pull them off when they have grazed the grass to about 1,100 pounds per acre,” he added.

That grazing schedule gives cows access to grass at the two- or three-leaf stage of growth, before plants have “hardened” to begin the reproductive stage, when nutritive value drops sharply. Crawford moves cows to new grass after each twice-daily milking. By removing cows after they have grazed plants to about 2.5 inches high, enough carbohydrate and root reserves are left for the plant to make quick re-growth. “It takes some fine-tuning to accomplish,” Crawford admitted.

Dairy grazing producers need a good understanding of basic plant and animal physiology, said Stacey Hamilton. “Most cool-season grass plants normally produce only three live leaves per tiller before a fourth leaf begins to develop, and the first leaf that formed 3 or 4 weeks ago begins to die,” he said. “Allowing the plant to grow beyond the three-leaf stage reduces forage quality for the cow and has little impact on increased yield.

“That’s why measuring pastures frequently is so critical,” Hamilton added. “A producer needs to know the amount of forage he has available now and plan for grazing pressure for the next 7 to 10 days. Knowing the amount of forage available over the entire grazing platform is called ‘average cover,’ which is the equivalent of knowing the amount of hay in the barn or silage in the pit at any given time.”

That’s why Rich Crawford measures and plots forage in each grazing paddock weekly.

About 10 years ago, Crawford and his colleagues established a pasture dairy operation at Southwest Center.

“From the start, we wanted to come up with features that would have a lot of borrowable ideas for producers,” he said. “We began with 60 cows on 96 acres. At the time, we considered 60 cows about the optimum size herd to provide a family livelihood. Since, then we have expanded the herd to 100 cows for a couple of reasons. One, 60 cows didn’t put enough grazing pressure on 96 acres of forage. Two, as input costs have climbed relative to milk prices, it takes more cows to provide the annual income a family needs to make it. In the next few years, we plan to expand to about 120 cows.”

Crawford has made other changes in the past decade.

“Early on, we went to a Holstein-Jersey crossbred cow,” he said. “A 1,400-lb. Holstein is not the best animal for a pasture operation, primarily because it’s too hard to get her re-bred. A Holstein-Jersey crossbred adds butterfat and other solids to the milk, makes a smaller cow that is easier to re-breed and one that withstands hot-weather stress better.

“We re-breed the F1 crossbreds to either a Holstein or a Jersey sire, depending on the composition and appearance of the cow,” Crawford added. “In other words, a crossbred cow that is more Jersey in appearance gets bred to a Holstein sire, and vice versa.

“We’re getting some heterosis [hybrid vigor] from crossbreeding,” he continued. “About a 6 to 8 percent boost in milk production, compared with the average of the two parent breeds. Other traits are harder to measure, but we’ve observed some advantages. We think our cows are healthier—whether due to being on pasture rather than pavement, heterosis or whatever. Our replacement rate is right at 20 percent—about double the longevity of cows nationwide.

“But in terms of milk production per cow, we don’t have many bragging rights at the coffee shop,” Crawford confessed. “Our cows average just over 13,000 lbs. of milk per lactation, with 4.2 percent butterfat. But we’re more interested in income production over costs than in production per cow.”

Crawford also instituted a seasonal milking program at the center. Cows dry off just before Christmas and begin freshening again in early February.

“That gives both cows and people a 6-week holiday,” he said. “And it’s good for both. However much you love cows and enjoy milking them, doing it 365 days a year can be a tough commitment.”

There are challenges to going seasonal. “Breeding for a tight calving window is a big one,” said Crawford. “We do a good job with AI breeding, and get most cows re-bred to calve in that February to early March period. But the whole idea of being seasonal forces you to do some things differently. For example, calving is fast and furious in that narrow time frame. We ‘mob-feed’ calves, and put a lot of emphasis on re-breeding cows.

“We start the grazing season on annual ryegrass, which usually makes good growth by early February,” he added. “A cow that calves in February reaches her peak nutritional requirement just when cool-season grasses are at their peak in growth and quality.”

“You can go seasonal with a pasture dairy at any time of the year,” said Stacey Hamilton. “But if you’re north of about the southern two tiers of counties in Missouri, you’ll probably want to give cows a furlough in mid-winter. South of that, you may want to consider fall freshening, with cows turned dry during those hottest summer months when heat stress is worst. Also, farther south, you may have better forage prospects for winter grazing.”

“The New Zealand model can be a good gauge to go by for producers considering seasonal, pasture-based dairies,” said Dr. Kent Haden. “New Zealanders approach an operation as a total land-plant-cattle equity business that looks at all assets and manages accordingly. They don’t have the same family or emotional ties to the land as many of us native to the Midwest. Their goal is not necessarily to maximize output, it’s to maximize income and return on assets.”

“New Zealand dairymen don’t stress production per cow,” agreed John Roche, research nutritionist with Dexcel, New Zealand’s largest dairy cooperative. “Still, we are historically the lowest cost, most profitable milk producers in the world, and most of our milk is produced in pasture systems. But if your goal is to produce 30,000 pounds of milk per cow per year, grazing is not for you.”

Click here to respond to this article