Heather Darby, University of Vermont Extension
Mike Gamroth, Oregon State University
Given the high price of grain, fuel, and forage, it is logical to hope for a longer-than-normal grazing season. Although traditional pastures generally become less productive in both yield and quality later in the season, several strategies can be employed to supply forage into the fall or early winter and effectively extend the grazing season by 60 to 90 days, thus reducing the need for stored feeds. These strategies can be categorized into two major groups: stockpiling (conserving cool-season forages in late summer for use in the fall and winter), and utilizing forage crops that continue to grow into the fall and early winter.
Stockpiled forage is a practice that allows the forage to grow and accumulate for use at a later time. Essentially cool-season forages are left to grow for the last 60 to 70 days of the growing season. This 70-day period can be achieved by terminating summer grazing or taking a last cut of hay in late July. The forage that grows during the autumn months is leafy and high in nutrition. Many farmers may "sacrifice" a few of their hay fields for fall grazing, especially if they plan to rotate into a row crop the following spring. Intensive grazing in these areas in the fall, with the accompanying manure applications, could be helpful to next year's corn crop. At times, those new to grazing tend to overlook their hay fields and the benefits grazing would have when used as part of the overall crop rotation.
All cool-season grasses and legumes can be stockpiled, but not all species are adapted to stockpiling, as most tend to reduce growth in the fall due to shorter day lengths and/or loss of leaves (and therefore quality) after a frost. However, tall fescue and bird's-foot trefoil are considered excellent candidates for stockpiled forage. These two species are well adapted to the practice because they continue to grow in the fall and do not lose leaves as readily after a frost. If tall fescue is planted for grazing, make sure to purchase an endophyte-free variety. Tall fescue has been shown to produce over a ton of dry matter per acre in the fall compared to half a ton/acre from other cool-season grasses. Yields can be increased by adding manure, compost, or approved nitrogen fertilizers, such as feather meal or fish emulsion, after the last grazing or hay harvest.
Since August and September are considered to be pasture shortage months, it may not be realistic for all farmers to set aside a portion of the summer pasture. Don't fret; there are other options for extending the grazing season.
Several forage species that are not as adversely impacted by the cool fall weather and short day length are available. Annual forages that grow best in the fall are small grains and forage brassica crops. Winter cereal crops such as wheat, barley, triticale, and rye can provide late-season grazing opportunities. Although not well documented, there may be a yield and quality benefit to mixing the various cereal crops. These grains should be planted in early- to mid-August at a seeding rate of 150 lbs/ac. Cereal grains are not heavy feeders but still require adequate levels of fertility. Manure will be able to cover the fertility needs of the small grains. Grazing from fall annuals should be available in October–November, and again in the early spring. Moderate grazing pressure will allow for the crop to recover and produce more forage in the spring. Small grain pastures are high in protein and low in fiber during the fall months. Crude protein levels range from 15–34% of dry matter.
Forage brassica is another highly productive fall annual for grazing. The standard brassica crops include turnips, rutabaga, kale, and rape. Turnip and rape are the shortest-season brassica crops. Livestock can graze the stems, leaves, and roots of turnips, but only the stems and leaves of rape. The crop will usually be ready to graze about 65–80 days after planting. Therefore a planting date in late July or early August would be preferable. The crop grows best during periods of low temperature of 40–60°F. Brassica crops grow best on fertile and slightly acid soils (5.3–6.8 pH). The crop does not grow well on poorly drained soils with high clay content. Turnip seed should be planted at 1.5 lbs/ac and larger rapeseed at 3–4 lbs/ac. The seed should be planted no more than one-half inch deep in rows 6–8 inches apart. Brassica crops are heavy feeders of nitrogen, and will require an application of manure, a legume plow down, or 100 lbs/ac of another certified-organic nitrogen source. Phosphorus and potassium requirements are similar to small grains.
Strip grazing small areas of brassica provides the most efficient utilization of the crop. This keeps the forage from becoming trampled and wasted. Grazing rape down to 6 inches allows rapid regrowth and may be regrazed in as few as four weeks. Turnips can also be grazed twice, but require more management. During the first grazing, only the tops of the turnips should be grazed. Make sure to leave 6 inches of stubble on the top of the turnip. During the second grazing, the cows can graze both the turnip tops and the roots. Typical dry matter yields obtained in numerous university and farm trials range from 3–5 tons/ac.
Brassica crops should be considered "concentrates" rather than "forage" when planning the animal's nutritional needs. Above-ground parts of brassica crops normally contain 20–25 percent crude protein, 65–80 percent in vitro digestible dry matter, and low fiber content. The roots contain 10–14% crude protein and 80–85% in vitro digestible dry matter. Brassica crops can produce per-acre amounts of digestible energy equivalent to corn yielding 115 bu/ac. Since the crop contains a high concentration of protein and digestible nutrients, brassica crops should not constitute more than 75% of the animal's diet. The diet should be supplemented with hay or grass pastures. It is always a good idea to introduce grazing animals to brassica pastures slowly. This will reduce chances of health disorders associated with these types of crops.
If you are looking to extend the grazing system, there are definitely options that can provide high-yield and quality feed. If you cannot decide what fall annual to plant, try mixing it up! Some farmers like to combine cereal grains with brassica crops. A combination of winter wheat or oats (60 lbs/ac) seeded with turnips (5 lbs/ac) can provide a high-quality combination of fiber, protein, and digestible energy!
This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.