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By Dr. Heather Darby, UVM Extension Agronomist
Given the high price of grain, fuel, and forage it is logical to hope for a longer than normal grazing season. However, our traditional pastures generally become less productive both yield and quality wise in early fall. Thankfully, there are several strategies that can be employed to extend the grazing season in the Northeast. Stockpiling or growing fall forage crops can extend the season 60 to 90 days into the fall and even 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 60-70 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. All cool season grasses and legumes can be stockpiled however some species are considered more favorable than others. Tall fescue and birdsfoot trefoil are considered excellent candidates for stockpiled forage.
These two species are advantageous 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 from other cool season grasses. Yields can be increased by adding manure or nitrogen fertilizers after the last grazing or hay harvest. Since August and September are considered to be pasture shortage months it may not be realistic to set aside a portion of the summer pasture. Don’t fret; there are other options to extending the grazing season.
There are several forage species that are not as adversely impacted by the cool fall weather and short day length. The annual forages that grow best in the fall are small grains and forage brassica crops. Winter cereal crops such as wheat, barley, triticale, or rye can provide late season grazing opportunities. The grains should be planted in early to mid August at a seeding rate of 150 lbs/acre. 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. Although not well documented, there maybe a yield and quality benefit to mixing the various cereal crops. Grazing 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 grains pasture is high in protein and low in fiber during the fall months. Crude protein levels range from 15 to 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 is the shortest season brassica crops. Livestock can graze the stems, leaves and roots of turnips while just the stems and leaves of the rape. The crop will usually be ready to graze about 65-80 days after planting. Therefore a planting date in late July through early August would be preferable.
The crop grows best during periods of low temperature of 40 to 60 degrees 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 per acre and larger rapeseed at 3-4 lbs per acre. The seed should be planted no more than on-half inch deep in row 6 to 8 inches apart.
Brassica crops are heavy feeders of nitrogen. Therefore an application of manure, legume plow down, or 100 lbs/acre of nitrogen will be required per acre. 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 re-growth and may be re-grazed in as few as four weeks. Turnips can also be grazed twice but requires 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 are 3-5 tons per acre of dry matter.
Brassica crops should be considered as “concentrates” rather than “forage” when planning the animal’s nutritional needs. Above-ground parts of brassica crops normally contain 20 to 25 percent crude protein, 65 to 80 percent in vitro digestible dry matter, and low fiber content. The roots contain 10 to 14 percent crude protein and 80 to 85 percent in vitro digestible dry matter. Brassica crops can produce amounts of digestible energy per acre equivalent to corn yielding 115 bushel per acre. Since the crop contains a high concentration of protein and digestible nutrients, brassica crops should not constitute more than 75 percent 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 can not decide what fall annual to plant….try mixing it up! Some folks like to combine the cereal grains with the brassica crops. A combination of winter wheat or oats (60 lbs/acre) seeded with turnips (5 lbs/acre) can provide a high quality combination of fiber, protein, and digestible energy!
Posted: to Organic Production on Fri, Aug 1, 2008
Updated: Fri, Aug 1, 2008