Grazing Annual Cover Crops

Grazing Annual Cover Crops

“Can we graze cover crops?”  The answer is yes, with an “it depends” attached.  It depends on soil conditions, the growth stage of the cover cro,; the reason you planted cover crops, and whether you’re involved in a conservation plan or program that requires other criteria.  Annual cover crops can be utilized quite well by grazing livestock, and they can also be part of a cropping system that can enhance the soil resource, but if grazed then it has to be managed correctly.

The nutritional values of most cover crops will meet the needs of most grazing livestock.  The ability to utilize annuals with grazing livestock allows longer rests periods for pastures, and also the ability to grow more forage, and graze longer reducing the amount of fed feed. Utilizing livestock on a cropland field can also be advantageous for increasing biological activity because of all the added flora of the rumen.  The majority of the nutrients that run through a ruminant animal are placed right back onto the ground from where they came.  The grazing of slightly more mature material mixed with a lower carbon to nitrogen (C:N) ratio species can help increase soil organic matter and get the nutrients in a more available form for the next crop.

These reasons can be positive as long as the primary purpose of the cover crop is not compromised.  Grazing must not cause any additional compaction problems, erosion, and/or rutting, and there must be adequate live plant material left behind.  This live plant residual is needed for adequate growth for the primary purpose(s) of the cover crop such as adequate cover for erosion control, winter survival, and adequate leaf area available for termination; sufficient root growth to reduce compaction and recycle nutrients; etc.

Dry or frozen soils are the ideal conditions to graze cover crops.  The livestock should not be grazing the cover crop under wet soil conditions unless a large amount (>2 tons/acre) of mature vegetation is present.  These larger amounts are normally only accomplished from a summer planting.  The key here is to not increase compaction…at all…nor to cause pugging that will cause erosion or hinder no-till planting of the cash crop next spring.

The cover crops also need adequate growth available before any grazing is initiated.  The start grazing height will vary some according to the species, but generally you want a minimum of eight (8) inches of growth for most species and rarely do you want to graze it down any lower than four (4) inches.  Maintaining adequate live plant residual is critical in keeping the plant growing and serving the intended primary purpose.

Livestock should not be left in any one area for a very long period.  Ideally, livestock should be moved or allocated new forage every 1-2 days.  Larger allotments can be utilized, but expect slightly less efficiency.  Livestock can remove vegetation very fast; keep a keen eye on the cover crops to make sure they are not overgrazed.  The cover crop should be checked every day, whether moving the livestock or not.

The best utilization and control is achieved by strip grazing annual cover crops.  Strip grazing is allocating out a set amount of forage that you know will meet the needs of the livestock for a set time frame and still maintain the required live plant residual after removing the livestock.  This can be achieved with reels of poly-wire and step-in posts.  Generally you will want three sets (reel and sufficient posts) for the front fence, the back fence, and the fence of the next move.

If grazing highly digestible forages add some roughage to slow the passage through their rumen enabling them to absorb nutrients.  The best solution is to not select only highly digestible, high nitrogen forages for a cover crop when they may be grazed.  These highly digestible forages move quite quickly through the livestock’s digestive system when grazed alone.  Planting a mix of forages that will provide both fiber and protein in balance is ideal.  An example could be mixing a warm season annual grass with a brassica in late summer to be grazed later that fall or early winter after the warm season grass has dried off.  Grazing cover crops in the early reproductive stage is the best way to slow the rate of passage through the animal.  You can also feed some hay or soyhulls to slow down the rate of passage.

Water should be provided to the grazing livestock and moved on a regular basis to keep them from spending too much time in any one area.  Portable tanks and water lines are a good way to do this.  Having hydrants or quick couplers located along one side of the field will allow multiple connecting sites.

It is rare to have good soil conditions for grazing throughout the entire fall, winter, and early spring.  Generally, do not leave livestock on the field all winter long.  They should be moved off the site if soil conditions dictate the need to prevent degradation, even if there is available forage still present.  Have a plan to move the livestock off of the field during wet periods, such as moving them to a perennial pasture or sacrifice lot, until ground conditions are okay to continue grazing.  Do not feed the livestock any feed or hay out on the cropland field to prevent excessive gathering and trampling.  Overused sites will become compacted!

Summer idle ground could also be planted to an annual cover crop mix, then grazed either during the growing period, or stockpiled for fall or winter use.

A cover crop mix to consider for grazing and soil health is:

Species                               Pounds/AC       

               Cereal Rye                         40

               Wheat                                 26

               Crimson Clover                 4

               Turnips                               1

               Radish                                 2


The rate of wheat could be increased to as much as 100 lb/ac.  If you are real adventurous you can add a couple of pounds of buckwheat and one pound of sunflowers. The buckwheat and sunflowers will freeze out at first frost.  Perennials properly managed build soil better and more cost effectively than annuals it is typically only recommended to seed annuals in fields with less than 50% desirable stand of cool season perennials like tall fescue because money spent on fertilizer instead of seed would yield more return.  The best pasture to drill cool season annuals in is warm season pastures like bermudagrass, crabgrass, dallisgrass and johnsongrass pastures.

Alternatives to Help Stretch Forage Supplies

Alternatives to Help Stretch Forage Supplies

Maintain a 3” minimum grazing height


Inventory Animal Demand and Forage Supply

  • Animal demand per 1,000 lb cow is roughly 20 -30 pounds of forage per day, 750 – 900 pounds forage/month or 9,000 – 10,800/year demand will be somewhat less for non-lactating animals and somewhat higher for lactating animals. Best to allow for 10% forage wastage. Most operations feed hay for a 90 days or more. Real good grazers or low stocked operations feed less days. On average producers feed hay 120 days. Example: 120 days x 30 pounds = 3600 pounds/cow + 360 pounds waste = 3960 pounds hay/cow/winter feeding of 120 days
  • Inventory grass, hay or other feed supply before April 1, July 1 and Oct. 1.
  • Inventory pasture – every acre-inch of forage is equal to 200 – 400 pounds of dry matter. A good average is 300 pounds/acre inch for good producing grass. Example: 5” of growth x 300 pounds/acre in = 1500 pounds of forage but typically livestock only consume around 50% of that so 750 pounds per acre.

As few as two or three plants per square feet with good stem diameter should rebound and make a good stand with good management and adequate moisture.  If the pasture is grazed for an extended time below 3”, the pasture will likely need re-seeding.

  • Some producers like to have a 20% carryover of hay for insurance in case of a long winter, extended drought, hay fire, etc.
  • Example: 20 head cows x 3960 pounds for 120 days = 79,200 pounds/20 head cow herd. If rolls of hay weighing 1,000 pounds and have not weathered much, this producer would need 79 or 80 rolls per winter. Twenty acres x 750 pounds/acre = 15,000 pounds of forage which would last about 25 days if 20 head were grazing and no additional growth occurred. (20 head x 30 pounds/day = 600 pounds forage demand)


Options to Stretch Forage Supply

If additional forage is needed one or a combination of the following alternatives could improve forage utilization and/or production.

  • Best to restrict animals to one paddock (field) until other paddocks re-grow otherwise all paddocks will be grazed so low that recovery is very slow and grass may even be killed. Another option is to continue to rotating animals on a schedule of 7 days or less.
  • When forage re-grows to five inches or taller allow animals access to four days or less of forage at a time will typically increase forage utilization by 20% or more.

  • Stockpiling tall fescue – setting aside 0.5 to 1 acre per cow extends grazing and provides higher quality grazing. Many producers stockpile tall fescue without fertilizing with nitrogen this is a consideration especially when fertilizer prices are high. Consider the following; fertilizing tall fescue with 60 pounds of Nitrogen (180 pounds of ammonia nitrate) will produce an additional ton of forage. Cost of Nitrogen at $0.40/pound of nitrogen x 60 pounds or nitrogen will cost $24/acre.If hay cost $24/1,000 pound roll a producer will produce 1,000 pounds of forage in addition to the cost of 1000 pound roll.. Some of the standing grass will be wasted due to trampling and manure damage. Depending on forage management, cattle will consume 50 to 70% of the 1,000 pounds providing a benefit of an additional 500 to 700 pounds above cost of nitrogen. Benefits may even be greater if hay waste is high.
  • Over-seeding pastures with winter annuals. Typically not feasible to overseed pastures with winter annuals unless tall fescue stand is less than 50%, even then, it is questionable but in an emergency, it is an option. Spring oats provide the quickest growth in the fall but die out during the winter. Winter oats are another option. Seed 4 bushels of oats by Oct 1. Rye is second quickest growth, seed 2-3 bushels/acre prior to October 15 for fall growth. Wheat seed 2-3 bushels/acre by October 1. Ryegrass generally just provides late winter quality forage the same time that tall fescue is growing. Fertilize winter annuals with a minimum of 45 pounds of nitrogen per acre.
  • Consider leasing additional pasture
  • Grazing fields traditionally used for fall hay, this is particularly a good option when you consider harvest efficiency of harvesting hay is typically 70% and strip grazing also has an efficiency of 70%. You get the same utilization for less cost! If land is not strip grazed, utilization will likely be at 50% efficiency. High fuel cost makes grazing hay fields in the fall the best option.
  • Early weaning will reduce stress on the cow and extend forage supply
  • Creep grazing Allowing calves access to higher quality forage than the cows. A demonstration farm in Bledsoe County creep grazed calves gained an additional 75 pounds grazing pearl millet in the summer. Winter annuals are a good option for creep grazing in the cool months. Some producers place their electric wire at about 30” above the ground to allow calves to free range choosing the best forage ahead of the cows. When weaned calves are grazing an adjacent pasture field to the mother cow, there is naturally less stress for both. Cows in better condition breed back sooner.
  • Feed ruminant friendly by products such as soyhulls, and corn gluten.
  • Irrigation, can improve forage production, it is important to have optimum stand, weed control, fertility, for irrigation to pay.
  • Adjust stocking rate, some producers like to stock for drought not high production, approximately 20% below maximum stocking rate. Plan for the worst scenario & hope for the best!


Management Strategies ahead of drought

  • Diversity of forages 70 % cool season, 30 % warm season. Different species within each group or season of forage can extend the growing season.
  • Multiple paddocks (cross fence to make five or more fields).
  • Proper grazing heights – A recent study at North Carolina State University showed that overgrazed pastures produced 37% less than pasture grazed to a 3” height.
  • Stockpiled forage– provides quality forage at the lowest cost
  • Maintain fertility utilizing soil test
  • Evaluate forage supply – Determine needs in advance with the end of seeding dates in mind. April 1 for spring seeded cool season grasses, July 1 for warm season grasses and October 1 for fall seeded cool season grasses.