Feed—especially winter feed—represents over half ofthe cost of producing livestock. The winter feed cost for a beefcow often ranges between $1 and $1.50 per head per day. Sincepasture costs one-half to one-third as much to produce asharvested feeds, extending the grazing season is one of the mosteffective ways to reduce costs. One can minimize feed costs bystriving to achieve as close to a 12-month grazing season aspractical.
Managing a forage crop by accumulating forage produced duringa period of active growth for grazing when forage growth hasended is called "stockpiling" or "deferredgrazing." Deferred fall and winter grazing can reduce theneed for hay feeding and the cost of maintaining cattle. Theamount and quality of forage available for grazing in late falland winter are determined by the starting date of accumulation,nitrogen fertilization rate, forage species present, and date offorage use.
Average snow-free wintering season
Experience has shown that most livestock accustomed to wintergrazing will actively graze through new snow that is 8 inchesdeep. Cattle grazing is limited by compacted or crusted snow, buthorses and sheep are adept at pawing through heavy snow or crustto reach the grass underneath. When you allow animals to graze indeep snow, it is important to keep an eye on body condition toensure that they are obtaining enough feed. The length of thesnow-free wintering season varies with elevation.
Forage species for deferred grazing
Forage species adapted to deferred grazing include perennialssuch as tall fescue, orchardgrass, and companion perenniallegumes; winter annual grasses such as rye and wheat; and annualforbs such as the brassicas. Among the perennials, the legumesare the most damaged by hard frosts and need to be grazed beforefrost damage and weathering cause excessive dry matter andquality loss. If planning to graze alfalfa after frost, keep inmind that bloat is likely to be a problem on recently frostedalfalfa.
Perennial grasses differ in their tolerance to freezing andweather damage. Reed canarygrass and bromegrass are the mostsensitive to frost damage; orchardgrass and Kentucky bluegrassare intermediate in sensitivity; and tall fescue is the mosttolerant.
Tall fescue is the best grass species to use for late fall andwinter grazing. In the late fall, stockpiled tall fescue can beleafy, palatable, and high in protein, sugars, and digestibleenergy. Livestock producers have mixed feelings about tall fescuedue to poor animal performance on this forage during the summer.With the exception of lactating dairy animals and pregnant mares,there is seldom a problem when tall fescue is used as part of asystem containing other forages.
Other perennial forage species have growth response and foragequality similar to tall fescue until they are killed by frost andundergo weather damage caused by rain and snow.
| Table 1. Fall grazing gain of gestating beef cows on stockpiled tall fescue in Ohio at the Jackson Branch, OADC (adapted from Boyles et al. 1998). | |||
Year | Days | No. cows | Daily gain |
1996 | 78 | 123 | 1.65 |
1997 | 89 | 131 | 1.64 |
1998 | 92 | 121 | 1.71 |
1999 | 111 | 120 | 1.85 |
4-year avg. | 93 | 124 | 1.71 |
Quality of deferred pasture
When pasture is managed for deferred grazing, a compromise hasto be made between yield and quality. Management that providesthe highest yield often produces lower quality forage. Foragequality and yield depend on date of deferral, soil fertility,legume content, rate and timing of nitrogen fertilizer, andweather conditions after growth ends.
The quality of stockpiled tall fescue is more than adequatefor dry mature livestock that need only to maintain body weight.If fertilized with 50 pounds to 100 pounds nitrogen per acre inJuly or August, tall fescue harvested in December will yield2,000 pounds to 4,000 pounds dry matter per acre, containing 8%to 16% crude protein and 60% to 65% digestible energy.
Crude protein content increases as nitrogen application dateis delayed from June to September. It increases with nitrogenfertilization rate, but decreases as deferral date andenvironmental conditions improve growth potential. Digestibilityand palatability of tall fescue increase in the fall as coolweather causes the nonstructural carbohydrates (sugars) toincrease. Forage deferred from August and September with nitrogenfertilization will have the high digestibility and intake (61%TDN, 2.5% DMI) but intermediate to low yields.
After killing frosts, forage quality will decline as rainleaches nutrients from the forages. This results in a gradualloss of crude protein and digestibility as winter progresses. Asnew growth begins in the spring, quality will increase.
A study at the Jackson Branch of the Ohio AgriculturalResearch and Development Center evaluated the body weight andcondition score gain by gestating beef cows grazing stockpiledtall fescue (Table 1). During the four-year study, body weightgains averaged 1.71 pounds per head per day, ranging from 1.64pounds to 1.85 pounds. Increase in body condition score over thefall grazing season averaged 0.71 unit, with a significantreduction in the number of cows in body condition 4 or lower,which is considered critical for cow productivity andprofitability (Table 2).
| Table 2. Change in body condition score of gestating beef cows grazing stockpiled tall fescue in Ohio at the Jackson Branch, OADC (adapted from Boyles et al. 1998). | ||
Body Condition score | Beginning (9-08-99) | Ending (12-30-99) |
Thin | No. cows | |
3 | 3 | 0 |
4 | 31 | 3 |
5 | 54 | 37 |
6 | 28 | 55 |
7 | 4 | 19 |
8 | 0 | 6 |
Fat | ||
When to start stockpiling
Highest yields of stockpiled tall fescue are obtained by earlydeferral. Due to low light intensity and cool temperatures,little forage growth occurs after early to mid-November. For highyield and quality, stockpiling of tall fescue should startbetween mid-July and mid-August. The earlier stockpiling starts,the greater the late fall yield will be. If fescue is stockpiledbefore July, quality will be lower, but yield will be about thesame.
Response to nitrogen fertilization
Adequate nitrogen will increase yield and quality ofstockpiled fall pasture. Nitrogen can be provided by growingclovers or by applying nitrogen from commercial fertilizer,manure, or chicken litter. Grasses need adequate nitrogen to growactively, produce proteins, and accumulate sugars during the coolfall weather. The accumulation of proteins and sugars makesfescue more tolerant to freezing and provides a greener, higherquality forage for grazing.
The response to nitrogen is reduced when legumes make up alarge part of the stand, when there is a high residual soilnitrogen from previous applications of manure, or if otherfactors such as drought limit plant growth.
Typical fall yield response per unit of nitrogen appliedaverages about 20 pounds dry matter per pound of nitrogen (DM/lb.N) applied. This occurs when nitrogen is applied at rates under100 pounds per acre (lb./a). On the other hand, when there is ahigh legume content in the stand or when other minerals ordrought limit growth, only 5 to 10 pounds DM/lb. N may beachieved.
The cost of additional forage produced with nitrogenfertilization can be estimated using the forage yield responseper pound of nitrogen and the price of nitrogen. If a yieldresponse of 20 pounds of forage DM/lb. N can be expected andnitrogen costs $0.36 per pound, then each additional pound offorage grown costs:
$0.36 / 20 pounds of forage = $0.018/lb or $36/ton DM
For a 1,200-pound cow eating 2% of her body weight (24 lb. DM), this would cost:
$0.018 x 24 = $0.432 / cow/ day
When using nitrogen, apply it at 50 to 100 pounds per acre,depending on the amount of forage desired. Fertilizer nitrogenshould be applied soon after stockpiling starts. If using urea,apply it just before a rain to reduce the loss of nitrogen byvolatilization. Ammonia formulations of nitrogen do not run thesame risk of loss as urea.
| Table 3. The average yield above a 2-inch stubble of stockpiled tall fescue in Virginia in mid-November based on date of deferral and rate of nitrogen fertilizer (11 site years reported by Green, Rayburn, and White). | |||
Initiation of deferral | |||
Sept. 15 | Aug. 15 | July 15 | |
Days of growth | |||
60 | 90 | 120 | |
Nitrogen fertilization rate | Average yield Nov. 15 | ||
0 | 884 | 1327 | 1769 |
50 | 1239 | 1858 | 2477 |
75 | 1416 | 2124 | 2832 |
100 | 1593 | 2390 | 3186 |
125 | 1770 | 2655 | 3540 |
Productivity, grazing management, and acreage requirement
Stockpiled tall fescue yield is determined by the number ofdays the stand is deferred and the rate of nitrogen fertilizerapplied. The dry matter yield will vary due to differences infall weather, soil conditions, and management before stockpilingand at harvest. Table 3 shows the average dry matter yieldobtained in Virginia based on days regrowth before November 15and nitrogen rate. The average yield over seven years in Ohio was3,576 lb./a, with 74 lb. N /a in August. Depending on frost andweathering damage, losses from November into December will rangefrom 0-1,000 pounds with an additional 600-1,200 pounds DM/a fromDecember to February.
If animals are allowed free access to stockpiled forage, theywill eat only a part of the forage and walk much of it into theground. By providing only what the herd will consume in one toseven days, more forage will be eaten and less wasted.
The highest utilization will be achieved by using daily stripgrazing. One acre of a dense 8- to 10-inch high tall fescuepasture will feed 50 1,000-pound dry cows for two to three days.In cold weather, forage intake may be higher. In rainy weather,treading damage may decrease utilization. Grazing to a 2-inchstubble increases forage use, decreases the competitive nature ofendophyte-infected tall fescue, and helps maintain more legumesin the stand. When grazing endophyte-free tall fescue, leave a 2-to 4-inch stubble at the end of grazing. This encourages avigorous spring growth that will improve long-term standpersistence. When grazing tall fescue during cold weather,livestock do not refuse the forage near manure piles as they doduring summer grazing.
When legumes are used to provide nitrogen, the fall growthshould be lightly grazed to use the legume before it is lost tofreezing weather. Weaned calves can make good use of thishigh-quality legume forage. The grass can be saved for later useby dry cows. If the legume forage is not used before or shortlyafter frost, the usable forage yields from legume-tall fescuestands will be reduced.
Tall fescue stands containing clover or lespedeza should begrazed close during the winter or spring to encourage theestablishment of legume seedlings. Dragging the pasture in earlyspring will spread the manure and seeds, ensuring a betterdistribution of seedlings and plant nutrients. By grazing thearea after dragging, the cattle will walk the seed into the soilsurface, improving seedling establishment.