An alfalfa-grass mix makes for a digestible dairy ration that can reduce the potential for laminitis. But not all alfalfa-grass pairings are created equal.
Some grasses mature faster or slower than alfalfa, making harvest more challenging. Some yield significantly more or offer higher potential milk production than others. Seeding rates vary by species. And, of course, grasses produce differently depending on the region. Those are just a few factors producers should consider when deciding which grass to seed with alfalfa.
“What is most important about the grass is tons per acre, as well as the digestibility of the fiber relative to when you can harvest it,” says Charlie Sniffen, a dairy nutritionist with Fencrest LLC, Holderness, NH.
When matching grasses with alfalfa, Sniffen looks for new species that have about 14% protein and 50% neutral detergent fiber (NDF). If the NDF gets much higher, digestibility falls off. The highly digestible fiber from grass can also tone down high-energy diets that cause laminitis, Sniffen says.
Determining the right alfalfa-grass ratio in a stand is important, too. For dairy-quality hay at optimal yield, stands should contain no more than 25% grass, recommends Jim Paulson, University of Minnesota (U of M) Extension educator.
Meadow fescue and tall fescue are Paulson’s top choices as alfalfa companion crops because of their yield, quality and survivability. The two had some of the highest yields of any grass mixed with alfalfa at trials he ran in 2011 and outperformed pure alfalfa stands. The alfalfa-meadow fescue combination averaged 5.43 tons/acre of dry matter at two sites, and alfalfa-tall fescue averaged 5.76 tons/acre. The alfalfa-only stand averaged 5.4 tons/acre at the two sites.
The two grasses also were of high quality, with alfalfa-meadow fescue averaging 14,090 lbs milk/acre and alfalfa-tall fescue averaging 14,920 lbs milk/acre. The alfalfa-only stand averaged 13,490 lbs milk/acre.
Tall fescue also matures in a similar time frame as alfalfa, adds Keith Johnson, Purdue University forage specialist. Johnson is high on improved varieties of the grass from a grazing perspective because of its firm surface for animal traffic and stockpiling ability. “It’s a species I’d have on my short list.”
Be sure to choose a novel-endophyte or endophyte-free tall fescue that’s been adapted to increase NDF digestibility, Paulson says.
Orchardgrass is the other species Johnson and Paulson recommend. The grass was the top yield and quality performer in Paulson’s alfalfa-grass trials, averaging, with alfalfa, 5.85 tons/acre of dry matter and 16,400 lbs milk/acre.
But orchardgrass only works well in dairy rations as a late-maturing variety. The grass has a range of maturity dates, and early maturing varieties can be stemmy at first cutting when included with alfalfa, Johnson says.
Timothy produces fairly good yields and quality, but peaks at first cutting and slows down during a hot summer. With alfalfa, it averaged 4.75 tons/acre of dry matter and 12,285 lbs milk/acre in U of M trials.
The perennial can mature too late to match with alfalfa, developing seed heads a week or more after the legume begins to flower.
“As a beef hay or horse hay, it probably works. But for overall productivity I’d probably stay away from timothy (when combined with alfalfa),” Paulson says.
Smooth bromegrass poses problems mixed with alfalfa because it should not be harvested on alfalfa’s four-week schedule. It needs to be cut every six weeks to persist.
Like timothy, smooth brome produces well at first cutting, but peters out during summer, Paulson says. The alfalfa-brome mix averaged 5.15 tons/acre of dry matter in his trials, but produced only 13,005 lbs milk/acre.
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Meadow brome seems to perform best in cooler climates, Paulson says. He lost a lot of plants at his southern Minnesota trial location, but not at plots farther north. Johnson has been impressed with the anecdotal results he’s seen from meadow brome in Indiana, but wants to see more research before forming a concrete opinion of it.
The alfalfa-grass mix averaged 5.4 tons/acre of dry matter in Paulson’s research, the same as the alfalfa-only stand. Its average quality was in line with alfalfa’s, too, at 13,430 lbs milk/acre.
Festulolium and perennial ryegrass are better-suited for Southern climates, because they don’t survive winter as well as other grasses. They also lack the yields of other grasses. Alfalfa seedings with perennial ryegrass averaged about 0.5 ton/acre less than ones with orchardgrass and tall fescue in Paulson’s trials – 5.3 tons/acre. An alfalfa-festulolium mix yielded even less at 5.14 tons/acre.
Reed canarygrass is slow to develop and was well behind the fescues and orchardgrass in terms of yield and quality in Paulson’s trials. The cool-season grass, with alfalfa, averaged 5.31 tons/acre in yield, and 13,725 lbs milk/acre.
In Indiana, reed canarygrass is considered an invasive species by many because “seed can find its way to tributaries and streams, and then you have a species that can be in spots where you don’t want it to be,” Johnson adds.
It does have its attributes. Reed canary grows well in different soil types, so it may be productive in a wet region or in a low-pH field, Sniffen says.
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