1Presented at the Washington Co. Sheep Symposium March 2, 2002, Meadowlands Pa.
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Profitable livestock production is
based on good marketing, cost control, and forage management.
Part of forage management is deciding whether to use native or
improved forages and how to optimize grazing management to
minimize the need for hay.
When choosing forage species for a
new stand, evaluate the species being considered on their:
Ecological niches of forage species differ and are related to climate, soil fertility, soil drainage, grazing management, and pest tolerance (Table 1). Plants growing in an established pasture are usually the ones best adapted to the current combination of site and management. If you want a different plant community, you will have to change the management, soil fertility, or soil drainage. Some species will not grow well on some soils.
The manager needs to select the forage species that will work best on the soil existing in the field and implement the management needed by that species for optimum production and quality.
In a field having variable drainage, it is beneficial to mix two species that complement each other. For example, birdsfoot trefoil or ladino clover mixes well with alfalfa as the legumes on fields with variable drainage. The trefoil or ladino clover will predominate in poorly drained areas of the field, and the alfalfa will thrive in the well-drained areas.
Growth habit determines the forage species' response to grazing or hay harvest. Orchardgrass, tall fescue, and bluegrass head out in the spring then tiller in later growths with their growing points near the ground. Because the growing point is near the ground, these species tolerate close, frequent defoliation. However, timothy, smooth bromegrass, reed canarygrass, and ryegrass joint with the growing point moving up above the soil surface in every growth cycle and can be injured if grazed or hayed at the wrong time.
Alfalfa, red clover, and upright birdsfoot trefoil are good legumes to use in hay mixtures with orchardgrass, tall fescue, timothy, smooth bromegrass, or reed canarygrass. White clovers (ladino and common), red clover, alsike clover, and prostrate-type birdsfoot trefoil are good legumes to use with orchardgrass, tall fescue, bluegrass, and redtop in pastures. Because of the competition between legumes and grasses, legumes do best under proper rotational grazing.
Growth distribution of forage species is a response to weather and day length. Some forages grow better in cool weather; others grow better in warm weather. Tall fescue is more tolerant of hot and dry weather than is orchardgrass; timothy is least tolerant of these conditions. Tall fescue is most tolerant of freezing weather in the fall and is the best for fall and winter grazing. The flush of spring growth in grasses differs among species. Orchardgrass heads out earlier than does timothy, with redtop being the latest cool-season grass to head. There are differences between varieties within a species. Hallmark orchardgrass goes to head sooner than Pennlate and has more vigorous fall growth.
Stand longevity is the result of a species' tolerance to disease and insects and its ability to move into openings in the stand. Some forage species increase plant size by tillering (Kentucky bluegrass, orchardgrass, tall fescue, timothy) or by growing larger crowns (alfalfa, red clover, birdsfoot trefoil). Other species invade open areas by moving growing points underground (Kentucky bluegrass, tall fescue, smooth bromegrass, reed canarygrass). Still others have growing points that move above ground (white clover). Species that move to fill openings can repair damage to the sod that occurs from hoof action and winterkill. Also, species and varieties that have good spring and fall growth (early-heading Orchardgrass and tall fescue) are competitive with winter annual and biennial weeds, resulting in fewer of these weeds in the stand.
The longest lived grasses in West Virginia, Virginia, and Pennsylvania will be orchardgrass, Kentucky bluegrass, endophyte-enhanced tall fescue, timothy, bromegrass, and reed canarygrass. The best legumes for general use are red clover, ladino clover, alfalfa, and birdsfoot trefoil. Seeding only a single forage species will result in other plants invading more quickly. These may be "weeds" or native forages. Proper mixes will reduce weed encroachment as long as the stand is managed properly. For example, a little ladino white clover (1 lb/a) in an alfalfa-grass mix will fill in openings as the alfalfa thins to reduce weed invasion. Smooth bromegrass does the same. A small amount of Kentucky bluegrass serves the same purpose in an orchardgrass-clover seeding. When mixing forage species, use ones that are compatible in growth habit and palatability and complement each other in growth distribution and ecological niche. Forage yield from pasture or hay is largely determined by:
A farm's soil and management affect which forage species are most adapted to the farm. Soil type and its capability can be determined from the county soil survey and should be used when choosing forage species. Soil fertility can be determined by soil testing and the needed fertilizers and lime can be applied. Table 2. Average yield of grass species grown in the Northeast.
The productivity of various grass species is compared in Table 2. Local ecological site conditions will improve a species’ performance compared to average. In hot, dry areas, smooth bromegrass may be one of the best grasses for hay production. In cool, high-elevation environments, timothy is highly productive. On poorly drained sites, reed canarygrass is most adapted. Table 3. Yield of alfalfa and red clover grown at sites across the Northeast.
The most productive legume on deep, well-drained soils is alfalfa (Table 3). On shallow soils having a yield potential of 2.5 tons or less of grass-legume hay, red clover will usually be as productive as or more productive than alfalfa (Fig. 1).
Figure 1. When grown on deep soils under the same environmental conditions, alfalfa is more productive than red clover. When the yield potential approaches 2.5 tons per acre, these two species are about equal.
For good growth, grasses require nitrogen from soil organic matter, manure, or commercial nitrogen. Legumes in mixture with grass can provide nitrogen to the grass through biological nitrogen fixation and N-cycling through soil organic matter. A good grass-legume mixture, containing 30% or more legume, will be about as productive as the grass alone fertilized with 150 pounds per acre of commercial nitrogen. If commercial N is used, it should be applied at 50 to 60 lbs per acre at spring greenup and after each harvest to a maximum of 180-200 lbs N/a/year to prevent nitrate from going into the groundwater. Likewise if manure is used as the nitrogen source, plant-available nitrogen should be limited to what the grass is able to use. Grazing and haying management affects the total forage yield, forage yield in the first cut, and the proportion of forage available in aftermath growth (Table 4). Table 4. The effect of grass growth stage at first harvest on the relative total yield, relative first-cut yield, and the fraction of the total yield obtained in the aftermath (mean ± standard deviation).
Grasses harvested at early head stage in the first cut will have only 84% of the total yield and 59% of the first-cut yield compared to cutting at postbloom. On the other hand, when harvested at early head, 60% of the total yield will be available as aftermath, while a postbloom first cut leaves only 39% of the total yield for aftermath. When aftermath grazing is used to manage the summer pasture slump, this can make a big difference. Legumes respond to harvest management in a manner similar to grasses.
Forage quality is little affected by forage species. Forage quality is determined by:
The single most important factor determining quality is the stage of plant maturity at harvest. As a plant matures, the forage increases in fiber, which reduces the crude protein and digestible dry matter content (Table 5). Table 5. The effect of grass growth stage at first harvest on hay’s crude protein (CP) and digestible dry matter (DM) content under normal mana gement after harvest and storage losses (mean ± standard deviation).
At our latitude first-cut hay digestibility decreases 0.33 to 0.50 percentage points for each day the harvest is delayed. Delaying harvest also reduces the amount of aftermath growth, critical in a grazing system to reduce the summer slump in pasture availability.
The second most important factor in determining forage quality is legume content of the forage. Legumes are of higher quality than grasses when harvested at the same growth stage. Legumes are lower in cell wall fiber (neutral detergent fiber), which allows animals to eat more. Animals that eat more forage gain weight faster or produce more milk. However, when they eat more it takes more forage to feed the same number of animals. Legumes are also higher in nonstructural carbohydrates (sugars and starches that are nearly 100% digestible) and protein.
If pasture or hay on the farm does not supply the nutrients the livestock require and the animals are not performing adequately or if the cost of supplemental feed is too high, then there may be the need to introduce and manage legumes into the stand or graze or harvest hay at an earlier growth stage.
Differences in plant species do occur. The most talked about one is date of heading in grasses. This is a management concern but only after identifying the species most adapted to the soil and management. One characteristic of late-heading species and varieties is that they are least competitive with weeds. There are negative quality components in some grasses such as endophyte-infected tall fescue and native reed canarygrass. These problems can be avoided by using endophyte-free or endophyte-enhanced tall fescue and new varieties of palatable reed canarygrass.
Conclusion
A profitable forage-livestock system needs to be low cost. One of the best ways to do this is to produce low-cost, high-quality forages. Pasture and hay quality and quantity need to be optimized for the livestock enterprise. Knowing the livestock's nutritional requirements and the quality of the forage produced will help the producer know if the quality is adequate. If quality is not adequate, the introduction of legumes and grazing or haying at an earlier growth stage will increase digestibility and protein content.
When mixing forage species, use ones that are compatible in growth habit and palatability and complement each other in growth distribution and ecological niche. |
