Winter Annual Forages for Cattle

By Jaymelynn Farney, beef systems specialist, Parsons

If moisture becomes available here is a short discussion about fall forage options for grazing.  There are two main classes of forages, cereal grains and brassicas, that have success growing in Kansas and can provide a cost-effective tool to provide gains for stockers and increase weight on thin cows.

Cereal grain options

Spring oats. Spring oats are usually planted in late February or March in Kansas. However, spring oats can also be planted in August or early September — and if done so, they will produce much more fall forage compared to other small grain forages in the fall before a killing freeze. In very mild winters, however, much of the spring oats planted in the fall might survive the winter in southern Kansas.

Spring oats can also be planted in a mixture with a winter small grain. The spring oat will produce most of the forage in the fall and then most likely winter kill. The winter small grain will overwinter and produce forage in the spring. Winter small grain biomass production might be less than if planted alone, but the combination of oat and winter small grain biomass will most likely be higher than winter small grain planted alone. If a mixture is used, plant oats at a 50% seeding rate and winter small grain at 100% seeding rate.

Winter wheat. Wheat is often used for grazing and grain in so-called “dual-purpose” systems. These systems are usually balanced between getting good forage and good grain yields without maximizing yields on either side.  For more information on dual-purpose wheat, please refer to the eUpdate article, “Managing wheat for forage and grain: the dual-purpose system”.

Winter barley. There are new, improved varieties of winter barley available with better winterhardiness, especially under grazing. Many of the newer varieties also produce more forage than older varieties. Barley produces palatable growth rapidly in the fall under favorable conditions. It is considered supe­rior to other cereals for fall and early winter pasture, but wheat, triticale, and rye provide better late winter and spring grazing. Barley has excellent drought and heat tolerance. Winter barley forage is typically the most palatable of the small grain cereals and feed quality is the highest, although tonnage of barley is usually less then triticale or rye.

Winter rye. Rye establishes fall pasture quickly. It also regrows rapidly in late winter and early spring. However, rye becomes “stemmy” and unpal­atable earlier in the spring than other cereals. Since rye is less palatable and higher in fiber than wheat or barley, cattle gains during grazing are normally greater on oat, wheat, triticale, and barley pasture than on rye pasture. Rye is the hardiest of the small grain cereals for overall tolerance to drought, heat, winterkill, and poor soil conditions.

Winter triticale. Triticale, a cross between wheat and rye, possesses the toughness of rye along with the quality of wheat. It can be grazed much harder than wheat and still recover to produce grain. Triticale and rye can be planted about a month earlier than wheat with a decreased risk of wheat streak mosaic. Planting triticale or rye earlier in the fall increases the amount of fall forage available compared to winter wheat. Triticale has longer effective spring grazing than rye, but not as long as wheat. Depending on the variety, winter triticale will head later than rye so the forage can remain higher in quality later into the spring. Heading date on all winter cereals should be a consideration if spring grazing is the goal.

Brassicas

Brassicas are a high protein and energy forage. From a nutritional perspective, the brassicas have an energy value close to that of corn and over 3x the protein value of corn.  When there is moisture the brassicas produce a very impressive amount of biomass.  Work done at the Southeast Research and Extension Center had found that cattle do prefer different types of brassicas – especially as related to grazing pre-or-post freeze.  If grazing with cows pre-freeze, cattle prefer a forage radish variety of brassica and after that really have no preferential picking of the other brassicas tested (purple top turnip, rapeseed, collard, yellow mustard, or kale).  After a freeze though, cattle did have a greater preference for grazing radish and rapeseed as compared to purple top turnip.  Cows are somewhat less discriminatory to eating the brassicas pre-freeze, but calves (less than 700 pounds) will actively select other things to graze before grazing the brassicas and this sometimes can inhibit gains.

Brassicas contain a chemical called gluconsinolate that has a bitter flavor.  This is undesirable for cattle and pre-freeze the concentration of glucosinolates are higher than after a freeze.  After a freeze this bitter flavor decreases and the high sugar concentration of the brassicas become more concentrated.

Brassica seed is very small and thus low seeding rates are recommended.  For cows 2-3 pounds of a brassica with a cool season cereal is acceptable.  For calves a maximum of 2 pounds of brassicas will not inhibit calf gains.  Some data from Nebraska has found that you can replace 20 pounds of cereal grain seed for each 1 pound of brassica seed and still have similar biomass production.  This becomes important when looking to determine the most cost-effective blend of cereal and brassicas to plant.

Grazing management

Fall grazing management is critical to the success of small grain pastures. Begin grazing when the plants are well rooted and tillered, usually about 6 to 8 weeks after planting. If the foliage is too tall when the animals are introduced, or if the crop is over­grazed, the plants will be more susceptible to winterkill. Make sure some green leaves remain below the grazing level. The minimum stubble height should be about 3 to 4 inches. Rye has a more upright growth pattern than most wheat varieties, so it should not be grazed as low. Winter barley is more susceptible to winterkill than rye or wheat. However, newer varieties of barley are exhibiting increased winter hardiness.

Forage quality considerations

In terms of overall forage quality of hay, barley is highest, followed by oats, wheat, triticale, and rye. Yet, the forage quality of all small grains in the vegetative stage is more than sufficient for any grazing animal. During the fall and early spring periods of peak production, the crude protein content of small grain pasture is nor­mally about 20-25 percent. Growing cattle require about 12 percent crude protein, thus no protein supple­ments are necessary.  If there is sufficient forage available stocker gains can be 1.5-2.5 pounds per day.

Small grain pastures can cause bloat. Daily supplementation with poloxalene (Bloat Guard) is highly effective in reducing bloat and is available in many different feeding forms. Feeding high-quality grass hay, silage, and/or an ionophore such as Rumensin or Bovatec can also provide some protection against bloat. Rumensin and Bovatec have also been shown to increase stocker cattle weight gains on wheat pasture.

Cows with high milk production grazing small grain pasture in the spring can experience grass tetany. To prevent this, provide a mineral supple­ment containing magnesium. Cattle should be started on the mineral two weeks prior to the risk of grass tetany.

When feeding brassicas, limit the amount to 75% of the final diet.  In addition to the glucosinolate leading to some palatability concerns, they can bind up iodine, zinc, copper, and manganese – all of which are important for things such as eye and hoof care, reproduction, and immune function.  Limiting the amount of brassicas can help minimize potential negative effects of production and also provide and make sure you see consumption of a high quality trace mineral program.https://enewsletters.k-state.edu/beeftips/2022/09/01/winter-annual-forages-for-cattle/

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