Extending the Grazing Season
by Garry D. Lacefield and Jimmy Henning, Extension Forage Specialists, University of Kentucky; Ed Ballard, Animal Systems Educator, University of Illinois
Grazing represents the cheapest way to feed ruminants on a cost per pound of nutrient basis. Stored feed is usually the single largest item in livestock budgets and cost or amount of stored feed is usually the best prediction of potential profitability in most beef cattle operations. Extending the number of days when grazed forages can be the primary source of nutrition can enable producers to be lower-cost and more efficient in producing livestock.
There are indeed many options available to producers in the “Heartland” for extending the grazing season. Options will vary in effectiveness based on environmental conditions (especially moisture), farm resources, animal requirements, existing forage, management, and overall goals of the individual farming operation.
In this presentation, we want to discuss several options that offer potential for extending the grazing season. Since the sponsoring states are primarily cool-season forage based, we will concentrate on extending the grazing season of cool-season grasses but will offer some examples of options for extending the grazing season when warm-season grasses dominate.
Since cool-season grasses are the primary pasture base for most of us, let’s first look at the cool-season grass growth curve (Figure 1). The typical growth curve for a cool season grass such as tall fescue shows growth beginning as temperatures warm in late-winter, rapid growth occurs through spring with up to two-thirds of the seasonal production by July 4th. Growth slows during summer with rising temperatures and reduced moisture. As late-summer temperatures drop and rains occur, growth resumes and can continue into early winter. The actual number of days that we can graze will depend on the particular growing season, along with our grazing and fertility management.
As we examine and experience our cool-season growth pattern, we see need for supplemental and/or complimentary forages (feed) during late-winter, summer, late-fall, early-winter, and winter. We are aware of no forage grass or legume that will make growth during our worst winters with snow cover and freezing temperatures; therefore, for most of us, we will need to provide some stored feed for those times. Our challenge is to optimize grazing and minimize the amount of hay or purchased feed needed. A second challenge is during those times we must rely on hay is to provide a higher quality hay supply. For many, our first step toward higher quality hay is to harvest at an earlier stage of maturity.
February to April: Fertilize for earliest possible green-up on some fields by applying N in early spring to cool season grass fields, ryegrass, or small grains. Rye will begin growing fastest and first. Expect to get on these pastures 7 to 14 days earlier than traditional turn out time, depending on the year. Fields that face south, that are better drained, and that do not have excessive winter growth of forage will warm up first and will start growing first.
April to June 15: This period is the time of maximum growth rates that will often require harvesting of excess as stored feed. Rotate pastures quickly and don’t try to utilize large percentages of the forage in any given pasture, or forage growth will get too far ahead on more paddocks or pastures than necessary. Consider leader/follower systems to maximize the animal gains and to raise the utilization levels of pastures. Harvest excess growth on time, based on stage of maturity, to produce high quality hay or haylage and to allow for larger amounts of regrowth forage (that will be primarily leafy, green forage of high quality).
June 15 to August 15: Growth during this period slows down greatly. Extend the length of time that pasture fields are rested and begin to leave more residual leaf area for cool season grasses. Warm season grasses can be very useful during this time to rest cool season grass pastures and also to provide a break from the endophyte stress of infected tall fescue. Fall forage crops like turnips and small grains can be planted in late summer to provide for more fall and winter grazing. During this time, identify fields of tall fescue that will be stockpiled (animals removed and fertilized with N) for extended grazing into the fall and winter.
August 15 to October 1: Historically, this period has the low pasture quality, due to high temperatures and extended dry periods in the fall. Consider feeding hay, in necessary, to maintain body condition and performance. Also, limit the fields that are overgrazed, especially cool season grasses. Even though it appears that growth is stopped and that animals cannot do any more damage, these fields grow back more slowly that fall than others that are left ungrazed. There is still opportunity to seed small grains or ryegrass, etc. that will give extra grazing. However, the fall growth of these crops is entirely dependent on moisture and days before low temperatures stop growth. Apply N for fall stockpiling in late August and early September, and remove grazing livestock from these fields at this time. Graze down clover hay fields during this period.
October 1 to November 1: Continue to graze clover hay fields, and plan to graze orchardgrass and/or bluegrass based pastures before fall rains make them decline in quality and available forage. If late-summer seeded turnips or small grains have enough growth, turn into these as well. Strip-graze or limit access to forage crops at this time since they have little or no ability to regrow.
November 1 to January 1: Alfalfa fields can be grazed down at this time if the ground will support hoof traffic. Bloat is a possibility on lush or freshly frosted legumes and make sure animals are full of hay before turn-out. Utilize early planted ryegrass or small grains if growth permits. Utilize stockpiled tall fescue to save hay. Stip graze to minimize trampling and waste and consider keeping animals off some fields during very wet weather. Plan to utilize most of the fescue before late December or early January. Stocker performance will decline rapidly as quality and quantity of forage declines in December (depending on weather and total forage available). Continue to use any small grain or turnip pastures as their growth permits.
January 1 to February 1: Usually a period that requires that hay or stored feed supply some or all of livestock nutrition. Stockpiled fescue can be useful forage but quality and quantity will be declining. Anticipate the coming calving of the spring-calving cow herd by raising the quality and amount of hay fed.
Utilizing Crop Residues to Maintain Beef Cows
Winter feed cost for maintaining the beef brood cow can represent a major cost for producing a calf. Many producers can take advantage of various crop residues which are left in the field following grain crop harvest. Ruminants have the unique ability to utilize residue materials such as grain, leaves, stalks, shucks and cobs remaining after grain harvest. These residues should be considered for their energy value since most are low in protein, vitamins and essential minerals. Dry, mature, pregnant beef cows can usually make best use of crop residues since their nutrient requirements are considerably lower than the requirements for other classes of beef cattle. Crop residues alone will not usually meet either protein or energy needs of cows nursing calves.
Quality and Quantity
Crop residues vary considerably in both quality and quantity which would be available for cattle. Table 1 lists some of the common residues as well as the quantity and quality you may expect to have in the field.
Although residues from either corn, soybeans and sorghum may be used, the major source of crop residue is from the corn crop following grain harvest. The corn plant has over 50 percent of its weight in stalks, leaves, shucks, and cobs. Considerable grain may also remain in the field after combining. Even with conservative combining techniques 4 to 6 bushels per acre may remain. A crop with a 100 bushel grain yield will normally yield from 2-3 tons of residue. Assuming only 25 percent utilization this dry matter residue can provide 80-100 grazing days. With this large amount of dry matter potentially available, considerations should be given to methods of feeding.
Table 1. Approximate feed value and yield of refuse materials
||15 - 20
||2 - 3
||2 - 3
Source: Salvage feeds for beef cattle, ID-9, University of Kentucky.
Feeding methods may range from "whole field" grazing, to restricted grazing, to mechanized harvesting and feeding. Obviously restricting animals or machine harvesting will probably require more labor and equipment than "whole field" grazing, but less feed will be wasted. Use the method which best suits your particular farm. For example, if you have small fields, you may want to graze them one at a time. If you have large fields you may want to strip graze in order to get more complete utilization of the feed.
Permitting animals to graze stalk fields is the most common way of harvesting since it is usually the cheapest and requires less labor and equipment. Whole field grazing limits the degree of utilization, as animals waste a large amount of the residues available through selective grazing, trampling, and overconsumption. Restricted grazing through the use of a temporary electric fence will result in more complete utilization. Allowing animals access to only a two to three week feed supply will force animals to utilize a larger amount of the dry matter thus wasting less.
Another grazing technique which can be used effectively is to allow those animals with the higher nutrient demands (such as young growing animals) to have first access to a stalk field. Follow them with dry cows. This system allows the better quality material to be selected by the first grazers and forces the lower nutrient requiring dry cows to clean up the remains.
- There have been cases where too much grain left in the field resulted in animals overeating and foundering.
- Prussic acid poisoning has been reported when grazing fields that were infested with Johnsongrass. This problem is greatest during the early frost period.
- Abide by all grazing restrictions from herbicides used on the crop. Many corn herbicides permit grazing while most soybean herbicides place some restrictions on grazing residue. Read and follow all label directions.
Large quantities of crop residues are available and can be used as winter feed for beef cows. Because crop residues are low in quality, they are best suited as a feed for mature, dry, pregnant beef cows. Residues are likely to be deficient in protein, phosphorus and vitamin A. With some residues, intake is low and energy is limiting.
Dry cows should be in good flesh going into the winter if they are to be fed residues. Cows that are thin or young animals should be wintered on higher quality feeds.
Stockpiling for Fall and Winter Pasture
Many cattlemen can take advantage of the late summer-fall growing conditions to obtain high quality pasture for fall and early winter grazing. This practice is called stockpiling. Several questions need to be answered relative to stockpiling such as: Which grass species is best for stockpiling? When should stockpiling begin? When, what kind, and how much fertilizer should be applied? When should the stockpiled material be used? What classes of cattle should be given access to stockpiled pastures? And finally, what grazing system should be used for most efficient use?
Grasses to Stockpile
The best grass for stockpiling is a cool-season grass which will retain its green color and forage quality later into winter. In addition, the grass should be somewhat resistant to low temperatures and have the capabilities of forming a good sod. Kentucky has two adapted grasses which have these characteristics; tall fescue and Kentucky bluegrass. Tall fescue produces more fall and winter growth than bluegrass (Table 2).
Table 2. Yield and crude protein content of Kentucky bluegrass and tall fescue produced from August 15 to December 1 under different levels of N fertilization at Lexington. Average of 3 years.
Source: Taylor, T.H. and Templeton Jr., W.C., 1976 Agron. J. Vol 68
Time to Begin Stockpiling
Late July-early August is the time to begin stockpiling for fall and winter use. Remove cattle in late July or early August, apply necessary fertilizer, and allow the grass to accumulate growth until November or December.
During the stockpiling period, August 1 to November 1, other available forages such as sorghum-sudan hybrids, sudangrass, bermudagrass, grass-lespedeza, and grass-clover should be utilized. After frost, alfalfa-grass and clover-grass growth should be grazed first before moving to grass fields.
A soil test should be taken to determine the phosphorus, potassium, and lime necessary. Nitrogen should be topdressed at the rate of 40 to 60 pounds of actual N per acre on bluegrass, and 40 to 100 on tall fescue. Kentucky researchers have shown that bluegrass fertilized with 45 lbs of nitrogen per acre had a yield increase of 20 pounds of dry matter for each pound of nitrogen applied when nitrogen was applied August 15 and yields taken December 1. In the same study, tall fescue showed an even greater nitrogen use efficiency with 24.4 pounds of dry matter for each pound of nitrogen applied. Additional studies have shown the greatest response for early application of nitrogen (Table 3). Nitrogen applications before August 1 may encourage the growth of summer grasses such as crabgrass and subsequently reduce the production of bluegrass and tall fescue. Source of nitrogen will influence efficiency (Table 4). These studies show that urea was approximately 85% as effective as ammonium nitrate on an equivalent nitrogen basis.
Table 3. Effect of time of nitrogen application on production efficiency of KY 31 tall fescue.
|Date N Applied
lb DM/ lb N added
SOURCE: Murdock, Lloyd W., 1982. Agronomy Notes. Vol. 15, No. 2, April, 1982.
Table 4. Effect of application date and form of nitrogen on yield (lb/a) of tall fescue 10 weeks after N application.
||Nitrate - N
||Urea - N
These studies have shown that with wise use and timing of fertilizer, high production can be obtained during fall and early winter. However, what is the quality of tall fescue in fall? The crude protein and digestibility of tall fescue is better during fall-early winter than any other time of the year. This increased quality in fall has been shown in many studies which agree with the data in Table 5 from the University of Kentucky.
Table 5. Seasonal percentage changes in chemical composition and digestibility of tall fescue.
|Crude Protein, %
|Digestible Dry Matter, %
*Digestibility Dry Matter Source: Buckner, R.C., 1975. Univ. of Ky. Coop. Ext. AGR-44.
Utilization of Stockpiled Forages
After frost, be sure to graze the grass-legume fields quickly before the plants deteriorate. After these fields are grazed, the stockpiled grass field or fields should be grazed. Light stocking will cause waste as a result of trampling. To make most efficient use of the high quality feed in stockpiled fields, install a temporary electric fence across the field dividing it so the area grazed first has a source of water and minerals. Once the animals have grazed this area off, move the fence back, opening up a new strip. Repeat this system until the entire field is grazed.
What Classes of Cattle Benefit the Most From Stockpiled Grasses?
Stockpiled grass is an excellent choice for fall-calving cows. It can be used after calving and during the breeding season when their nutritional needs are greatest.
Spring-calving cows may benefit most from grazing stockpiled grasses if they are in thin body condition in the fall. They can regain condition while grazing and be in better shape going into the winter. Spring-calvers in mid-gestation which are in good body condition may not need as high quality feed and could use lower quality feed then. Over-conditioning cows in late gestation may increase birthweight of their calves.
Growing, weaned cattle can also be grazed on stockpiled fescue. Backgrounders can lower the feed costs of their operations by utilizing stockpiled grasses.
Stockpiling of adapted cool-season grasses such as tall fescue and bluegrass extends the grazing season, provides a good return of high quality forage for each pound of nitrogen fertilizer applied (providing other elements aren’t lacking and the nitrogen is applied early), and provides the beef cow herd an ideal place for wintering and calving.
Many options exist that offer producer potential for extending the grazing season and thus reducing the amount of stored feed needed. Each option must be evaluated in reference to the overall farming operation, resources, economics, and goals. Growing conditions, especially moisture, will play a critical role in all of the options listed above. Overall, grazing management and fertility can extend existing pastures and reduce the need for establishing other forage species.
Our challenge is to develop strategies that will optimize grazing consistent with sustainable, agronomic, and economic livestock production.