High grain prices have placed – some would say returned to their rightful place – an even greater importance on forage crops. With so many factors affecting quantity and quality – from seed to feeding – researchers in all areas continue to seek ideas and answers for dairy producers.
Compiled by Dave Natzke
Dairy-quality grass forage
Perennial grasses can provide good agronomic, economic and nutritive complements to alfalfa, according to Paul Peterson, University of Minnesota Extension forage agronomist. Researchers examined several perennial ryegrass and tall fescue seeding ratios with alfalfa. They found:
• Perennial ryegrass/alfalfa mixtures looked very good in their first production year and produced dairy-quality forage, but the ryegrass did not persist well.
• Low-alkaloid reed canarygrass was the most persistent and compatible grass with alfalfa, but produced somewhat inferior forage quality.
• Strategic use of nitrogen fertilizer and/or manure on alfalfa/grass mixtures may be economical during spring and late summer.
Alfalfa’s yield/quality tradeoff
Studies by the U.S. Dairy Forage Research Center addressed the trade-off between yield and quality for each cutting of alfalfa, according to Geoff Brink, research agronomist. The study was conducted at three locations – central Pennsylvania, southcentral Wisconsin, and southcentral Idaho – planting similar alfalfa varieties. Alfalfa was harvested in spring, early summer, late summer and fall.
• Yield was highest for the spring harvest period at all three locations.
• Quality was highest for the spring harvest period in Pennsylvania and Wisconsin. In Idaho, forage production was dependent on and maximized under irrigation beginning in early summer. Forage quality declined most rapidly in the early summer at all three locations. In Pennsylvania and Wisconsin, the decline in forage quality is slowest in late summer.
Using Milk 2000, an index which combines forage yield and quality into a single term to estimate milk production per acre:
• During the spring harvest period, milk per acre plateaus approximately 10 days after vegetative stage.
• During the late summer harvest period, potential milk production continues to increase because yield is increasing while forage quality does not decline as rapidly as in early summer.
Sweet corn waste
Sweet corn waste (SCW) poses management challenges, according to Paul Dyk, UW-Extension dairy agent. Low dry matter content can lead to a high volume of leachate. SCW typically contains leaves/husks about a foot long, making it difficult to pack. Lab analyses of the SCW samples show wide variations in protein, carbohydrate, fat and minerals. Dry matter ranged from 19.8% to 29.9%. Fermentation analysis showed a high level (>3%) of acetic acid, making feeding rates a concern; typical acetic acid levels in corn silage range from 1.0% to 1.5%. Be sensitive to variation, and adjust prices for quality, if possible. (firstname.lastname@example.org)
Dry samples with a hair dryer
Penn State ag engineer Dennis Buckmaster designed a simple homemade tool to determine moisture content of forage samples. The homemade “Vortex Dryer” combines a standard home hair dryer with CPVC pipe. It is easy to use, requires less supervision than the microwave oven method, and requires less drying time than a Koster tester. Moisture estimates were within 1% of the actual value 95% of the time. For more information, including how to build and use one, see the Penn State Extension Fact Sheet titled “A Vortex Forage and Biomass Sample Dryer.”
Pack, don’t just level
With the speed of today’s harvesters, bunker packing often results in leveling, not packing. What is gained in the field is lost in the silo – in more ways than one, warns Thomas Kilcer, certified crop advisor from Kinderhook, N.Y.
In addition to feed quality lost to spoilage and poor fermentation, storage capacity is stretched. Research by John Conway, with Cornell’s Pro-Dairy program, showed the fastest, cheapest, most effective method to increase storage capacity is to dramatically increase packing. One local farm increased silo capacity 50% by improved packing.
Radial tires on tractors are designed with low pressure for a large footprint to reduce soil compaction – the opposite of what you want in the silo. Increasing the pressure in the tire (within manufacturers’ specifications) will increase the tractor weight’s packing efficiency.
Vegetative proteins of alfalfa and many other forages are rapidly degraded in the rumen, and not efficiently utilized to capture all of the potential nutritional and economic value, according to Ron Hatﬁeld, plant physiologist. Partially degraded protein molecules are even less efficiently utilized – resulting in a need for protein additives and additional nitrogen waste in manure. Plant proteases released during the ensiling process begin degrading the vegetative proteins even before they are fed, one reason ensiling practices emphasize rapidly decreasing silage pH to limit protease activity.
However, red clover, even under poor ensiling conditions, typically has minimal protein degradation. A precision breeding approach used at the U.S. Dairy Forage Research Center inserted an enzyme present in red clover into alfalfa, with positive results. Researchers are also working to test the feasibility of co-ensiling forages with plant materials or plant extracts to preserve the greatest possible amount of the native protein.
Equipment technology adds management capabilities
Equipment technology can help forage management from the field to the cow, according to New York and New England Pioneer Hi-Bred dairy specialist Kevin Putnam.
Near-infrared (NIR) technology installed on choppers is helping speed forage information collection, reducing time needed to collect and send samples to a lab. The research is being used to evaluate corn silage hybrids, but has applications for commercial farms, as well. NIR installed on commercial choppers will provide almost instant moisture information, which has a major impact on bunker packing and fermentation.
Precision management software on mixer wagons can monitor feeder error and weigh backs, helping track feed inventories. And, Pioneer is working with some chopper manufacturers to install super low-volume inoculant applicators – linked to yield monitors – to apply the exact rate of inoculant needed, even in fields where tonnage is variable.
Inoculants not a ‘quick fix’
When used properly, inoculants can help ensure the forage that comes from your field maintains its quality through feedout. But which forage inoculants are right for your operation?
An inoculant shouldn’t be used as a “quick fix” to make up for mistakes in harvesting or storage, according to John Anderson, Mycogen Seeds forage nutritionist. Silage inoculants work by adding Lactobacillus-producing bacteria to accelerate the acid production needed to preserve the silage. Silage treated with inoculants stabilizes faster and will maintain higher amounts of nutrients.
Identifying specific needs can help determine which type of inoculant will work best. For example, inoculants that aid in fermentation usually contain lactic acid-producing bacteria and are used primarily on low dry matter forage crops, like grass and alfalfa. Materials like corn silage and cereal grains are more prone to aerobic spoilage and may benefit from inoculants designed to improve stability. (www.mycogen.com)
Interseeding summer annuals into pastures was the topic of a dairy tour in Folsom, La., hosted by Ronnie Bardwell, Louisiana State University AgCenter area dairy agent, and Allen Tarver, a Louisiana equipment salesman, cattleman and forage producer. Tarver interseeds forages into Bahia sod using a piece of equipment called a “plant-o-vator,” which opens a furrow (5½ inches deep and 3 inches wide, every 12 inches ) deep enough to apply fertilizer beneath the seedbed, and only disturbs a small area of the topsoil. It’s designed to hold rainwater to keep it available for the plant roots. (www.lsuagcenter.com/news_archive/2009)
Frosted corn silage?
A lot of corn for silage could be in the field when the first frost occurs. According to Ev Thomas, high sugar levels in immature corn act like antifreeze, making milk-stage corn somewhat tolerant of a moderate frost. As long as there’s green leaf tissue – or even if only the stalk remains green – the plant will continue to mature.
Don’t overestimate the drying effects of frost. Although leaves may appear crispy, leaves are only about 10% of whole plant dry matter. Much of the moisture (and yield) is in the stalk, which often dries slowly. Harvest timing should be based on a dry matter test.
If the husks are still tightly wrapped around the ear once the plant is dead, start harvest ASAP. A tight husk holds in moisture, and ear molds can start within a week under warm conditions.
A hard frost may kill many naturally-occurring fermentation bacteria, so use a bacterial silage inoculant. (The same goes with alfalfa harvested after a killing frost.) Make sure you get a forage analysis before starting to feed it. Compared to well-dented corn, immature corn is often higher in protein, but lower in starch and energy.