Translating forage into milk
How much forage can one formulate into high-producing dairy cow rations?
Over the past decade, herds nutritionists have advised dairy producers to increase forages (grasses, alfalfa, corn silage) from 50 percent of the diet (on a dry matter basis) to 55 percent or more. In fact, today in the Midwest, herds use 55-60 percent forage inclusion.
"Ultimately, diets need to be formulated to keep the rumen healthy and produce milk efficiently while limiting nutrient waste, all at an economical price to keep the farm profitable," said Kenneth Kalscheur, USDA-ARS, U.S. Dairy Forage Research Center.
Reporting to members of the Midwest Forage organization, he said while there are many benefits to increasing forage concentration — higher milk components, improved cow health resulting from normal rumen function, lower culling rates, increased cow longevity and lower feed purchases — there are some challenges for increasing forages.
First, more high-quality forage will be needed over the course of the year, meaning more forage acreage, harvesting and storage capacity. Second, forage production can be challenging, but it will be important to harvest high quality, highly digestible forages to support high milk production.
As the herd at Orthland Dairy at Cleveland grew and as the Orths increased the effort to get more forage into their dairy cows, they realized they needed to make some management changes.
"We collaborate with our nutritionist on how to get more forage into the diet without sacrificing milk production," Steve Orth said.
He added, "When we did our own forage harvesting, we could never keep up and get it in the bunk at peak quality because our equipment was too small. Improved feed quality has helped our milk production, and that's important."
The ration includes Brown Mid rib corn silage that he describes as a genetically-modified corn specifically designed to benefit dairy cattle.
"This forage is very digestible and nutritious for dairy cattle," he said.
Their plan appears to be working because since getting up to 60 percent forage in the diet, they have maintained a healthy herd that averages in the area of 95 pounds of milk a day and a rolling herd average in the 31,000-pound range.
Jim Digiangi milks 2,400 cows at Darlington Ridge Farm.
"Forages make up a significant portion of our cow's diets," he said. "We try to keep a one-and-one-half year supply of corn silage and haylage on hand."
In order to do this, they raise some of their own forages, and they also buy haylage and corn silage from local farmers.
Keith Bolsen, professor emeritus at Kansas State University, understands why farmers like Orth work with custom operators to get their forages in quickly.
"If there is too much forage cut at a time," he said, "it is important to have enough packing equipment to keep up with the delivery of feed.
"Density and shrink are directly related. The target should be 16 pounds of dry matter per square foot. Surface spoilage contributes considerably to dry matter losses."
For corn silage, he said packing each layer adequately before the next load is added is important.
"Add another pack tractor and put a kernel processor on the chopper," he suggested. "Increase the pack tractor weight and make sure to do it after each layer. Packing longer at the end of the day is a waste of time and fuel."
Bolsen also suggested having multiple corn silage locations rather than one big pile in order to remove enough feed each day to prevent spoilage.
"We need to make sure that we have a uniform and consistent supply of silage every month, every week, every day," he said.
He added, "If you look at the multiple corn hybrids we're planting today on dairies and the BMRs, multiple cuttings of alfalfa or multiple cuttings of other hay crop silages or nontraditional forages like summer and winter forages, that silage can be monitored for different nutritional qualities, so pay attention to silage inventory control."
Three traits make it hard to ensile alfalfa. These include low dry matter content, high buffering capacity and low sugar content. He said as the conductor, the feed manager's job is to determine when to cut, how much to cut, how long and when to start and stop.
Maintaining a steady 40 percent to 45 percent dry matter can be a challenge. Bolsen said 37.5 percent to 42.5 percent is a compromise, but he is not willing to go down as low as 35 percent.
The Midwest Forage Organization recently offered some suggestions for feeding higher forage diets, based on several research projects around the country.
✔Strive for consistent quality with minimal variation. Monitor forage inventory, and consider changes in cropping or feed sourcing. Allocate the highest and lowest quality forages to the most appropriate groups.
✔Analyze the forages frequently, looking at things like particle size and digestibility.
✔Adjust rations as needed based on forage analyses.
✔Target feeding management, including silage face management, aerobic stability, palatability and feed delivery.
✔Monitor the TMR mixer management.
✔Make dietary adjustments to higher forage concentration in small increments.