Definitions
Financial Aspects of Grazing Management Systems
Management-Intensive Grazing (MiG)
Pasture Growth Dynamics and the Effects of Grazing
Pasture Quality
Planning Procedures for Establishing Rotational Grazing Systems
Stocking rate is a measure of the number and type of animals assigned to a grazing system. It is affected by the stocking method (how animals are grouped for herding purposes, e.g., leader/follower systems, etc.), and by the amount of pasture made available to the grazing herd, i.e., paddocks can be made smaller with temporary electric fence. While this can be useful, it is the balance of forage supply to livestock demand over time that is most important.
Rotation length is the time needed to return to the first paddock grazed. With intensive (variable) rotational stocking this varies with the time needed to get the target dry matter production per acre accumulated to adequately feed the class of livestock being pastured. This gets back to the dry matter question. The farmer needs to establish a target level of dry matter production per acre that is needed for the livestock being pastured. The recovery (rest) period is the time needed to regrow enough forage to meet that targeted forage DM. Actually, rest period is a misnomer because the grass is not resting; it is growing without being grazed simultaneously. The recovery period will vary from 14-15 days during a period fast growth to about 40-45 days during slow growth periods. The cut-off during slow growth periods should be based on the rate of senescence of leaves. Some grasses and legumes start to lose as much digestible dry matter as the stand gains in new leaf when recovery periods exceed 40-45 days. Thus, there is little point holding a stand much beyond this time.Residency period is also known as grazing period. Cattle do not graze 24 hours a day, but either residency or grazing period represents the total time available for grazing. We all know they take a break to get a drink, or ruminate, or rest. Therefore, grazing period is the time the animals spend in a fenced-off pasture before being moved to another. The shorter the grazing period; generally the higher the utilization, provided the forage on-offer is in balance with the livestock demand requirement for whatever time period they have to graze it. The grazing period should be flexible from one day to 7 days long. If you are a weekend farmer, you may move livestock once a week and suffer a loss in forage utilization and animal weight gain. If you want highest gains, move them daily. You will also end up with the best utilization unless you give them way too much forage by over-sizing the paddocks.
However, it should be kept in mind that all of these concepts (rotation length, grazing, and recovery period) are not absolute They are relative terms calculated to provide general guidance. There simply isn't any substitute for daily observation of your grazing groups and paddocks. Forage growth rates do not change abruptly, but gradually. Therefore, it is necessary to have transition periods when rotation lengths, grazing and recovery periods are adjusted by season according to the forage plant's needs for regrowth and maintenance of a healthy stand. Actual rotation lengths, grazing and recovery periods are thus a function of how fast or slow the forage is growing. Forage growth rates depend on previous grazing pressure, the amount of sunlight available, time of year and temperature, amount of rainfall, soil moisture reserves, and soil fertility. The animal demand side also directly affects these periods, i.e., which class (lactating vs. not lactating, beef vs. dairy) and ages (mature vs. growing) of animals are present. All classes and ages of cattle have different nutritional needs, which affect the quality and quantity of forage needed. If the animals are growing or lactating, the herds demand for forage changes with time and needs to be projected into the future.
It may or may not make economic sense. The decision to covert a conventional dairy farm to a grazing-based dairy should consider all aspects of the farm business and concentrate on whether or not a profitable change can be made. Grazing-based dairy production relies on the cows to harvest forages and reduces the need for assets (machinery, equipment, facilities, etc.) for forage production, harvesting, and storage and manure management. Managers abandoning conventional dairy production will still have ownership costs associated with all the machinery, equipment, and facilities even if they are not used. There can be both advantages and disadvantages to this change. Advantages include, longer useful life of existing assets, added cash flow from sales of assets no longer needed, less demand for labor for forage production and manure management, more time to spend managing the cow herd, and lower annual repair and maintenance costs on existing equipment and facilities. Disadvantages mostly center around the continuation of ownership costs and/or debt payments on assets no longer used in dairy production. As discussed in a previous question, grazing-based dairy production often results in lower output per cow and lower total costs per unit of output. This continues to be the driving force in making the decision to convert, abandon, and/or reduce the use of existing assets in the business. Clearly, the decisions must be made on overall profitability and in conjunction with the business and personal choices of the farm family. That is, will the farm family business be better off by moving to grass-based dairy production?
The answer may be it depends. The critical factor to keep in mind when making a change to a grass-based dairy is that you must make a greater reduction in the total cost of producing milk than any reduction in income that arises from selling less milk (i.e., you must increase profits). Unless you can achieve this reduction in total costs the move to grass-based production will not be profitable. Studies have documented that grass-based dairies produce less milk per head than conventional dairies. In addition, studies have documented that grass-based and conventional dairies are equally likely to be profitable or unprofitable. Therefore, paying close attention to cost control and measures of profitability are the critical factors in a change to grass-based milk production.
The first step before investing funds in any change to your farm business is to accurately plan for the change and to anticipate the problems that may arise during the transition period from conventional grass-based production. Once you have planned for the new system and have projected that the change will in fact lead to a more profitable farm business, then begin to measure the progress of your change. That is, begin to use the management tools that you have at your disposal - business and production records. The 2 major factors that you should concentrate on are monthly cash flows and annual analysis of returns to owner equity or returns on investment. Monthly cash flows monitor the flow of cash through the business and can indicate significant changes in the outflow of cash from your projected needs. Returns to owner equity and investment measure overall growth and financial stability of the business pre and post change. Assistance in financial management and analysis can be obtained form your local extension office.
What is seasonal production? Seasonal milk production, matching peak milk production to peak pasture production can be an attractive alternative for dairy producers seeking to maximize the use of pastures and reduce need for stored forages. Seasonal production is based on a 12-month pattern: all cows are bred to calve within about a 60-day window and then the whole herd is dried off at the same time. Milk production ceases for a specific period (30-60 days) before cows calve the following year.Historically, agricultural prices have shown a seasonal price pattern that corresponds to changes in production (supply) and demand. Milk prices show similar trends, with prices lowest in the spring and summer when production peaks from the spring flush of milk. Prices peak in the fall when children return to school and spring calving cows are approaching their dry period.
In Virginia, November is the month with the highest seasonal price and May is the lowest month. Seasonal dairy producers freshening the entire herd in February and March and reaching peak production in April and May will routinely sell the majority of their milk at the lowest seasonal prices. In addition, seasonal herds will produce the least amount of milk and dry-off their cows during the time of highest seasonal prices (October-February). Thus, seasonal diary producers face the prospect of reduced total income based on the historical price patterns.
The decision to produce milk seasonally is complicated by the related biological and economic conditions. Farm business managers must be able to cut their total cost of milk production to compensate for the lower average price received for their milk. In addition they must be astute reproductive managers of the herd to ensure an adequate number of cows entering the herd during freshening season. Other considerations include:
- Milk base: In Virginia, many farmers own Virginia Milk Commission Base (VMCB), which allows them to sell milk at a higher price than the average milk price received by dairy producers. The pounds of VMCB owned by a farm must be met for the farm to retain this price advantage. Farmers who do not ship milk during a specific period (30 days) can lose their base. VMCB can be bought and sold within Virginia; therefore, it has value to the owner. Farmers who own VMCB should not produce seasonally and put their right to sell milk at a higher price in jeopardy. One option would be to sell their base and use the proceeds in the farm operation. This decision should only be considered after close financial analysis about the long-term and tax implications to the financial stability of the farm business.
Virginia is served by a number of dairy cooperatives that have a variety of base plans and incentives programs to ensure a steady supply of milk to their plants. These base and incentive programs offer farmers a higher average price for their milk or pay more for milk production in low supply periods (fall and winter). Producers who own base in a cooperative or can take advantage of incentive plans to ship milk in low supply periods must also consider all the financial implications before deciding to go seasonal.- The Human Side: Dairy producers who produce milk seasonally like having the cows dry for a specific period because they get a break from the daily requirements of milking and the activities required to keep a constant flow of milk through the bulk tank. "We can take a vacation," they say. In addition, they also like the predictability of the work routine, "We freshen and raise a mob of calves for 2 months, breed cows and heifers for 2 months, and then we do not have to do those chores for another 12 months."
- Cash flow: The drawback to stopping milk production is the drastic reduction in cash flow the farm family will experience during the dry period. Farm businesses with monthly debt service requirements or farm businesses that provide the majority of family income must plan very carefully their cash flow needs. Development of sound budgeting procedures for the farm and family are a must to ensure adequate cash flow and debt service capacity for the months without income.
- Management: Seasonal dairying compresses most of the management and work activities into short periods that allow little room for mistakes. To keep the seasonal dairy production system on a 12-month cycle, managers must plan intensely and gear-up for each of the seasonal activities. As with breeding, cows must be breed to calve in a 60-day or shorter window to maintain herd size and reduce the number of replacements that must be purchased. At the same time, pressure is experienced for trying to successfully raise the large group of calves that will be needed for replacements or to provide additional income from heifer sales. Failure of management to successfully carry out any of these tasks during the compressed time frame can have drastic consequences on the profitability of the farm business. Year-round farms can have a month of unsuccessful breeding that may impact only one-twelfth of the herd and suffer limited adverse consequences. Consequently, a month of unsuccessful breeding for a seasonal herd could impact more than half of the herd.
- Costs: The decision to produce milk seasonally must be based on the farms projected profitability and the ability to generate cash flow before any dairy system is selected.
Measuring the financial success of a farm business depends directly on keeping both production and financial records. The three critical measures all business managers should be familiar with are liquidity, solvency, and profitability. Liquidity is the ability of the farm business to provide cash when needed. Solvency is the ability of a farm business to provide financial growth and stability, i.e., are total assets increasing and greater than total liabilities. Profitability is the ability of the farm business to produce net income above all costs. Farm business managers should have a working knowledge of each of these financial measurements of business success. These measures start with an income statement or summary of the cash expenses and income, similar to the information contained on the farm's Schedule F tax return. In addition to cash income and expenses, farmers should annually record the value of all assets and liabilities used in the business on a balance sheet or net worth statement. On the production side, farmers should know how many units of output are sold, that is, how many cwt. of milk and/or livestock are sold. These units of output then can be used to calculate the cost per unit of production, for example cost per cwt. of milk. At a minimum, farmers should annually prepare and evaluate, with a professional, an income statement, net worth statement, and livestock production records that include units sold and total livestock numbers. In addition, farmers should consider developing a monthly or quarterly cash flow statement to track and monitor the flow of cash through the business. Often overlooked, but very important is establishing a record system that tracks family living expenses to indicate where money drawn from the farm business is spent.
The up front investment costs to establish a rotational grazing system is highly dependent on a given farm's site-specific conditions. Perimeter fencing usually exists, so only interior fencing and gates will need to be added, and in many cases alternative-watering facilities may also be needed. If watering facilities are already in place, then obviously these costs can be avoided or minimized. On the other hand, if a well must be drilled including all costs to supply water to paddocks all over the farm, then the start up cost is going to be substantially higher. If perimeter fencing and some internal paddocks already exist along with adequate water, then the marginal costs of polywire cross fencing may be the only added costs. Typically farmers can expect start-up costs for development of a rotational grazing system with standard gravity-fed water development and fencing to range from $150-$500 per acre. This is a lot of money, but keep in mind that these investments are long-term improvements to the farm that have been documented through case studies to increase net income by $75 to $150/acre per year. It should also be noted that cost/share funds are available to help deal with the cash cost of conversion.
Farm business managers have a number of choices when it comes to selecting a records system to aid them in monitoring the financial health of their business. Clearly, the most popular method involves using computer software to automate the drudgery of keeping up with expenses and income of a farm business. In addition, farmers also can continue to use hand-kept record systems or hire an accounting firm or record keeping service to maintain their records. However, the choice of a record system should be based on the managers needs for service, diagnostic and planning tools. Service entails: Reporting and documentation for federal, state, and local taxes; on-farm labor records and state and federal reporting; loan applications and reporting to creditors; and documentation for insurance claims. Diagnostic/monitoring entails: Organizing records into balance sheets (statement of net worth), income statement, and cash flow. Planning entails: Use of records to develop enterprise, partial, and whole farm budgets; projected income statements and cash flows; and tax planning/management.Once deciding on the critical service, diagnostic, and planning requirements of your record system, selection boils down to picking a system that meets these needs of your business. Use of a computerized system is strongly recommended and can help reduce the frustration of generating reports and analysis of your business' success. There are 2 major categories of computerized systems to choose from: 1) generic record keeping or accounting software designed to meet the needs of most businesses, and 2) agricultural record keeping and accounting software designed for farm applications. Listed below are some of the advantages and disadvantages of these general classes of software.
Type Advantages Disadvantages Examples Generic
Software- Less expensive
- Updated frequently as changes in the technology occur
- Well written documentation and help
- Web-based help and features, e.g., on-line banking, electronic filing of taxes, etc.
- Not designed for agricultural business
- Lacks ability to track quantities
- No integration with production records software
Quicken, Microsoft Money, QuickBooks, MYOB, and Peachtree Agricultural
Software- Designed for agricultural use
- Tracks quantities of inputs and outputs
- Designed for a particular commodity, e.g., dairy, cash grain, etc.
- Integration of field, machinery, and livestock production records
- More expensive
- Updated less frequently
- Longevity of company?
Farm Works, Doanes, FBMS Before selecting a software package for your farm business, contact your local extension office, other farmers, and your accountant for suggestions and experience with computerized record keeping software.
Managing risk and specifically drought is a very difficult and costly issue. Farm business managers need to consider all options available based on local conditions and markets. Conventional beef and dairy farms have traditionally relied on planned surpluses of pastures and/or harvested forages to cover forage deficits due to droughts. Grass-based farms seeking to maximize profits of the farm by grazing all available lands for pastures will incur forages deficits during droughts. Alternatives to consider are varied and include: 1) establishing savings or a line of credit to support purchases of forages during droughts and/or increased use of energy feeds and other supplements to extend existing pastures; 2) if storage space is available, purchasing emergency hay supplies during surplus years or if storage space is not available leasing space from neighbors for emergency hay storage; 3) establishing a minimum level contract with neighbor(s) to supply you with hay at fixed prices; 4) culling less productive animals to reduce forage needs; 5) building into your production system some insurance in the form of surplus hay production capacity; and 6) if a reliable source of water is present, investment in an irrigation system. The decision to use one or all of these alternatives will be dictated by economic condition and severity and length of the drought. Local economic and weather conditions often dictate the market for forages in the East, more so than national conditions, since forages are bulky and expensive to transport. In some cases, hay may be very expensive relative to corn or other high-energy supplements. Therefore, choosing only one of these alternatives as the answer to your drought management maybe shortsighted. As conditions change, you need to be able to adjust to the cheapest source of feed for your animals.Irrigation is a special case. Deciding to invest in an irrigation system is a long-term capital investment and needs to be evaluated relative to its ability to generate sufficient returns to the farm business to pay for itself. In most cases, investments in irrigation systems should be incorporated into the ongoing farm plan and used throughout the growing season to increase stocking rates and available forages, and hopefully profits. Otherwise, the farm business will be required to cover the investment costs even if it is not used. In all reality this can be a very expensive insurance premium relative to setting aside money to buy forages or concentrates during a drought.
Profitability of a farm business is a measure of how well the business is covering all costs, including cash (e.g., fertilizer, feed, interest, etc.) and fixed costs (depreciation/obsolescence of machinery, equipment, buildings, etc.) and costs associated with management and owner/ operator labor. The amount of money left over after subtracting all costs from all income is profit. Conventional farms and grass-based farms can both be profitable. Making the decision to change to a grass-based farm should be based on careful analysis of the alternatives that will make the most efficient use of both the farms and the manager's available resources that meet with the farm family's long-term goals. The resources and management required to develop a profitable grass-based or conventional farm can be very different. Grass-based farms rely very heavily on manipulation of the animal-plant system to provide forages while minimizing use of harvest equipment and storage. Conventional farms rely on production of harvestable forages that can be closely monitored for quantity and quality in a controlled feeding system. The tradeoffs between the 2 systems require that management pay close attention to how their resources are used to produce a pound of milk or meat for the lowest per unit cost. Thus, a farm with land that is not suited to row crop production may be better suited to grass-based production. In addition, grass-based production may be a better choice for a beginning farmer with limited access to capital for machinery, equipment, and buildings. Thus, grass-based production allows for maximum investment in livestock and minimum investment in facilities and machinery.
No. The way a pasture is managed can have a major impact on the presence of weeds. Production practices that favor the vigorous growth of desired forages will minimize the effects of weedy plants. Effective pasture management programs should:Proper grazing techniques can be an effective and economical weed management tool. By grazing in such a way as to maintain and improve a dense forage stand weeds face much greater competition from desired forages. However, animals tend to selectively graze certain plants because of differences in palatability. Consequently, broadleaf weeds such as horse nettle may become more prominent over time. One method to overcome selectivity is to increase grazing pressure thus, decreasing animal selectivity. Flash grazing (putting a lot of cattle on a small area for a short time) is one method of controlling weeds. Be careful to not reduce stand density and be sure that the weeds are not poisonous. Some examples of poisonous weeds are buttercup, butterfly weed, wild cherry, cocklebur, elderberry, poison hemlock, larkspur, white snakeroot, sneezeweed, and star of bethlehem. If mowing is necessary, be sure to time it in order to prevent seed production. Mow when weeds are in the stem elongation stage, but before flowering. Repeated close mowing several times a season over a three to five year time span can effectively suppress some perennial weeds from spreading such as horse nettle by reducing root reserves. If herbicides are needed, make sure legumes do not make up a substantial portion of the forage base and be sure to observe livestock restrictions (both for grazing and hay production) for the herbicide used. Read and follow herbicide labels. An example of controlling broadleaf weeds in fescue is: (1) Spray for the broadleaf weeds. (2) Observe livestock restrictions while allowing the fescue to stockpile. (3) Then graze the stockpiled fescue over the fall and winter. (4) Lastly, renovate the fescue with clovers by frost seeding to improve forage quality and ground cover.
- Maintain proper soil pH and fertility levels
- Make use of controlled grazing practices
- Make use of mowing only when timed to proper stage of maturity for targeted weeds to prevent formation of seeds
- Insure new forage seedings become well established
- Practice pasture renovation pastures when needed.
Stocking rate is expressed as land area per unit animal (e.g. 2 acres per cow-calf pair) or animal unit per land area (e.g. 2 steers per acre) over an extended period of time. Bringing additional land in or out of a grazing system can alter stocking rate. During the spring flush, land can be taken out of the grazing system to make hay, thereby matching pasture forage supply to demand, effectively increasing stocking rate. Alternatively, additional pastureland is often required in summer months to compensate for reduced productivity of cool-season forages. Spring hayland and/or warm-season pasture can be added to reduce the farm's stocking rate. The problem is you still have to calculate livestock forage demand and know how much forage on-offer you are going to have to make an intelligent decision on the stocking rate.
All pastures (cool-season or warm-season) in the produce an uneven supply of forages over the year. Therefore, you need to establish a target level of forage dry matter per acre level that you want to have as a minimum before turning livestock into a new paddock or pasture. When growth rates are fast, this target is achieved fast. When growth rates slow, this will take longer to achieve. The target may not be achieved in 40-45 days before the grass needs to be grazed to prevent loss of dry matter. Paddock size will need to be adjusted to provide the proper amount of forage on-offer thus, expanding pasture acres in summer and reducing acreage in spring and fall. Providing a buffer is the best way of managing around this problem. In a cool-season based system the most typical buffer is to rotationally graze one half of the pasture acreage in the spring, haying the other half, not needed by the animals. In the summer allow animals to rotationally graze the whole acreage. Other buffers include the following management strategies. Use warm-season grasses in some of the paddocks, these grasses will not be ready for grazing until the warm summer months. Run two sets of stocker cattle on the pasture in the spring, moving one set off to feedlot in mid summer. Use nitrogen fertilizer on selected paddocks in August to increase production for fall grazing.
As growth rate increases, yield potential increases. Since cool-season growth rates are greatest in spring, this is the period of greatest yield potential. Reduced growth rates associated with heat and drought in summer result in reduced yield of cool-season forages. The implication of this in a grazing system is that either hay must be made or additional cattle must be used in spring and/or additional acreage must be added to the grazing system in the summer to compensate for the change in cool-season forage growth rate and yield.
Ideally, animals should be turned into a paddock when there is 2000-2500 lb. dry matter per acre. This is achieved with 4-6 inches of growth with Kentucky bluegrass and 8-10 inches of growth with orchardgrass. This ensures adequate availability of pasture forage for near maximal intake by grazing animals. It also ensures that the paddock has had adequate opportunity to grow and replenish carbohydrate reserves prior to being regrazed. Pastures should not be grazed down to the ground. Rather, 1-1.5 inches should remain for bluegrass/white clover pastures, 2-3 inches for orchardgrass/alfalfa stands, and 8-12 inches for switchgrass. Adequate residual height ensures appropriate soil cover, which reduces erosion and soil temperature and increases water infiltration, vigorous regrowth, reduced weed encroachment, and adequate forage availability for optimal intake by grazing animals. Cool-season pastures typically require 14-21 days of regrowth between grazing in the spring, and 35-42 days in the summer.
Maximum production per animal and per acre cannot be achieved at the same time. However, a compromise can optimize the two.Establishing the proper forage allowance on-offer to the herd and grazing management are the two most powerful tools producers have for influencing the level of production (per head and per acre). In selecting a grazing system (paddock numbers and size, forages desired, water availability, forage on-offer, and rotation length, etc.) consider the following: forages, type of livestock, and the level of animal performance desired.
Effect of varying grazing pressure
When forages are undergrazed, gain per head is higher, primarily influenced by forage quality through selective grazing. However, gain per acre will be low due to a lower forage utilization rate.
When forages are overgrazed, selectivity decreases, lowering quality of consumed forage. Intake is also restricted since the last few bites are smaller than the ones at the start of the grazing period. Therefore, gain per animal is lower due to decreased forage availability but gain per acre is higher within the optimum range shown in the graph above due to increased utilization. Note however, that gain per acre will decline as well under extreme grazing pressure. When utilization goes over 80 percent, gain per acre must decline. Intake drops dramatically. Refer back to livestock intake versus utilization graph.
The graph above suggests a possible compromise by offering enough forage to the herd to avoid both under and over grazing. While neither gain per animal nor gain per acre is at maximum, both are optimized to achieve good utilization rates.
The frequency of rotation and amount of forage on-offer influences animal selectivity. If individual gain is the goal, rotate faster and offer enough forage to keep utilization at about 50%. If gain per acre is important, rotate slower and increase utilization towards 80 percent, recognizing that forage quality and individual gain or milk production will decrease. Regardless, grazing periods should not exceed five days to avoid regrazing newly emerging tillers. For dairy producers, grazing period should not exceed one day to keep milk production at the highest plane achievable given where the herd is in its lactation cycle.
Stocker operators and dairy producers will benefit more from a very intensive rotation (daily or less) to keep intake up. To improve utilization, these types of herds need to be followed by a herd that has a lower dietary need that can graze down the pasture further without being harmed.
Management-intensive grazing MiG is a term used to describe a grazing system that requires the livestock manager understand the plant-animal system and the economic consequences of each decision. Management-intensive grazing takes into account the physiological needs of both plants and animals, and strives to optimize both. Thus, MiG systems inherently involve rotational grazing. MiG systems require greater investment in alternative watering facilities and fencing and more management in the forms of knowledge, observation, and intervention. However, MiG systems generally create more balance between animal demand and forage supply; promoting higher forage yields, uniform levels of forage quality, improved harvest efficiency, reduced labor requirements, and improved output per unit of land.
Hot weather reduces the energy efficiency of Cool season grasses resulting in slower growth rates during summer months. Conversely, warm season grass forages are more energy efficient during the warmer part of the growing season. Thus, cool season forages are more efficient and adapted to cool weather (less than 70oF) while warm season forages are more efficient and adapted to warm weather (greater than 70oF mean air temperature).Forage Growth/Temperature Relationships
Forage Type Temperature Range Optimum Temperatures Cool-Season Grasses 40-85 70-90 Warm-Season Grasses 60-110 90-100 Legumes 40-110 75-90
Yield Distribution of warm and cool-season grasses. Gerrish and Roberts, 1997 Missouri Grazing Manual. Note how yield distribution relates to temperatureAdaptation to different temperature ranges means cool and warm season forage types are complimentary in a pasture system. An appropriate combination would result in an improved distribution of forage availability throughout the grazing season. This could reduce the need to adjust livestock numbers to meet available feed supply, feed hay during summer and winter months, and/or promote a longer grazing season leading to improved animal performance during the summer months. There maybe potential cost savings associated with reduced feeding of conserved forages (hay and silage).
Grazing does not increase forage yield relative to a well-managed mechanically harvested forage system. However, the production of animal products from a grazing system will equal the output from a dry hay system at less then half the cost. The important management principles are to match the timing (when) and intensity (how close) of grazing to meet the needs of the plant and the animal; keeping the forage in a vegetative growth stage adequate for high animal intake. Proper management will help maintain a dense pasture sod and optimize plant growth and quality relative to the pasture's environmental condition.
Establishing a warm season forages stand will require a higher investment in seed and achieving a successful stand on the first planting is not guaranteed. While the principles are the same as for cool season perennial forages, the specific details are different. The management principles also depend on the kind of warm season perennial forage used in your grazing system e.g. native or introduced species.Tall growing native species: native forages require the beginning and ending grazing heights to be much higher than for cool season forages. Grazing should begin at 20 to 24 inches and go no lower than 8 inches. The last grazing before the onset of fall should leave at least 10 to 12 inches of residual material. The reason for the higher ending heights is that the growing points on native warm season forages are much higher than for cool season forages. By leaving an appropriate ending height, regrowth is enhanced and stand longevity improved. This is not wasted feed since these grasses have thick stem bases that are unpalatable anyway. Native forages should only be rotationally grazed to ensure the best possible quality and to insure stand longevity.
Low growing introduced species: introduced warm season forages, e.g. hybrid bermudagrasses and caucasian bluestem should be grazed beginning at a height no higher than 8 inches for caucasian bluestem and 4 inches for bermudagrass. The ending heights for caucasian bluestem are 4 inches and for bermudagrass is 2 inches. These forages must be grazed more closely than the natives to maintain maximum quality and acceptable animal performance. With caucasian bluestem, leave enough time after the last grazing for an 8 to 10 inch regrowth before the onset of fall.
Like the natives, introduced forages should only be grazed in a rotational system to ensure adequate quality and stand longevity. Hybrid bermudagrass if grazed to close will die out and common bermudagrass if present will start to take over. Common bermudagrass is a very low producing species similar to bentgrass.
Animal performance is quite good on both the natives and introduced species when they are properly managed. However, warm season forages are less forgiving of mistakes than cool season forages when poorly managed.
High grazing intensity, or how closely the pasture is grazed, increases forage utilization but can decrease daily forage intake per animal and decrease animal production per day. If high grazing intensity continues for long periods of time the productivity of the pasture willdecrease, the sod weakened, and weeds will encroach. On the other hand if the grazing intensity is not high enough forage is wasted, grasses may produce seed heads that are not palatable, weeds that would be grazed by livestock under a higher grazing pressure are left to go to seed, and legumes are often lost due to shading. Pasture utilization for the sake of the animal and the plant should range between 40 to 80 percent of the grazable forage. Seventy percent is a good goal to shoot for consistently to allow some leeway from undergrazing and overgrazing.
What is the seasonal pattern of cool season forage production and quality? In a typical year, cool-season grasses and legumes produce one-half to two-thirds of their total production during the spring. This is followed by a period of lower productivity during summer months (where mean July temperature is greater than 70oF) and moderate productivity during the fall. Favorable temperatures and moisture contribute to the high spring productivity whereas; hot and dry summer weather limits cool-season forage growth. Cool-season legumes, in particular alfalfa, have better summer productivity than cool-season grasses like orchardgrass. . As forages rapidly mature to reproductive stages in spring, their forage quality declines due to increased stem and fiber concentrations reducing forage quality. Season also affects forage quality, forage quality of cool-season species is greatest in the early spring and fall, and lowest in the summer. In addition, high summer temperatures also contribute to lower digestibility.
There are five major reasons to consider adding warm season perennial forages to a grazing program.
- Available Forage will be more evenly distributed over the summer months. This will reduce the need to adjust livestock numbers to match the available forage supply, allow animals to continue gaining during the summer, allow adequate recovery time for the cool season forages, and reduce hay feeding (lower labor, time, and costs).
- Warm season perennials, especially the natives (switchgrass, big bluestem, and eastern gamagrass) help reduce the effects of drought. They naturally grow well in hot weather, have a deeper root system than cool season grasses, and utilize water more efficiently. In addition, they begin growth later than cool season forages leaving accumulated soil water for later spring and summer plant use. This reduces the dependency of warm season forages on sporadic summer rainfall.
- When properly managed, animals perform very well on Warm season perennials. While forage tests indicate that they are lower in quality than cool season forages, animal performance does not suffer because:
The true test is animal performance and grazing trials of warm season grasses in Virginia show that gains of 2 pounds or more per day during the summer are feasible with good management.
- forage tests are calibrated to cool season forages
- structural parts of warm season perennials are more digestible than cool season forages
- animal use of warm season perennial protein, is used more efficiently.
- Native perennial warm season forages improve wildlife habitat without compromising livestock benefits
- Warm season forages make more efficient use of nutrients and energy Warm season perennials require a higher level of management than cool season forages, so start small to learn the management needed to make best use of these forages. Then a better decision can be made on whether to plant more. The acreage planted to warm season perennial forages depends on producer goals. However research supports that acreage of 15 to 25% may be appropriate for maximum complimentary effect in the East. Plant it on sites that are droughty or less fertile so cool season grasses do not invade and compete too heavily with the warm season grasses. In the temperate East, cool season grasses have the competitive advantage of starting their growth much earlier in the spring than warm season grasses.
Pasture quality is best defined in terms of animal performance per head while pasture yield is best defined as animal production per acre. To have high pasture quality the pasture needs to be (1) kept in a vegetative growth stage, (2) have adequate height and tiller density at the time of grazing, and (3) 25-30% legume in content by weight to maintain high dry matter intake by livestock. A compromise has to be made between quality and yield. If the pasture is grazed lightly (4-inch stubble on orchardgrass) the animals will eat more per head and have high performance but animal production per acre will be low. If the pasture is grazed moderately close (2-inch stubble) animal performance per head may be reduced but production per acre will be increased. The closer grazing along with proper rest interval helps maintain legumes in the stand. This increases forage quality and fixes nitrogen. Pasture quality is at its highest during cool weather in spring, and in the fall when plants are high in sugar content due to low tissue respiration relative to photosynthesis.
Forage quality declines with days of regrowth and maturation. This is due largely to the accumulation of dead leaf and stem material and the increased production of lower quality stem and reproductive material, and leads to a lower leaf:stem ratio. Consequently fiber concentration increases, resulting in lower digestibility and intake potential, as the forages mature. Crude protein concentration also declines. Total productivity is also reduced when forage is allowed to regrow for too long. This is due to shading of lower leaves and tiller buds, the source of subsequent yield. As leaves and stems die, standing dead residue increases. Livestock try to avoid eating this dead residue and causes them to graze less efficiently. This dead residue also has only half the digestible dry matter of green leaf material. This low digestibility also reduces animal intake when they inadvertently eat some of it.
In general, as forage plants grow, quality declines, fiber content increases, protein and digestibility (energy) decreases, and the leaf to stem ratio declines. In addition, older leaves and stems start to die. This produces standing dead material within the green leaves lowering quality. When plants are small, quality may be very good but availability is reduced. If we consider that meeting the nutritional needs of livestock from pasture relates to both quantity and quality, then we must know total usable nutrient intake, which is a product of dry matter intake and forage digestible nutrient content. Both availability (yield) and quality (protein and energy) must be considered. This implies the need for compromise. While quality and yield cannot be maximized at the same time, they can be optimized. Farmers should develop management strategies based on how plants grow, that is, beginning grazing while the forage is still leafy yet tall enough to provide optimum availability and end grazing at a point to allow for the best possible regrowth. This strategy will seek to optimize both quality and yield. The time of each grazing event is called a grazing period. While this can vary depending on class of animal, time of year, and producer goals, it should be short enough to prevent grazing of newly emerging tillers. These periods can range anywhere from 1/2 to 1 day for grazing dairies, 1 to 3 days for stockers, and 2 to 5 days for cow-calf herds. In most situations, grazing periods should not exceed five days in order to prevent grazing of newly emerged tillers.The time of each nongrazing event is called a recovery period. This time should be sufficient to allow for regrowth of the forage to a desired beginning grazing height. The number of days usually varies with season. Cool season perennial forages will need recovery periods ranging from 14 days in the spring to up to 40 days in the summer. By knowing the desired number of days for the grazing and recovery periods, we can calculate the number of fields needed to achieve this. The following formula can be used to estimate the number of files: recovery period (days) + number of herds = number of fields or paddocks., for example, a grazing period of four days and a recovery period of 40 days (longest anticipated period) , with only one herd, yeilds (40 + 1) 41 fields or paddocks.. A rotational grazing system accounts for grazing and recovery periods based on plant growth and will optimize both yield and quality resulting in better stand persistence and animal performance.
Forage demand is the product of dry matter intake per head per day, the number of animals in the herd, and the average size of animals in the herd. Grazing livestock will consume forge dry matter at a rate between 2.0 and 3.5-percent of their body weight per day. The lower rate applies to dry beef cows and the higher rate to lactating dairy cows with little supplementation. Lactating beef cows, calves, and stocker cattle consume forage at a rate between 2.5 and 3.0 percent of body weight. Since calves and stocker cattle are suppose to gain weight over the season the average weight of the herd increases as the season progresses so the forage demand for the herd increases over the season unless animals are removed from the herd.
Grazing animal nutritional needs vary during the year and must consider quantity and quality of the pastures and feeds offered. In addition, the availability and ready access to a clean supply of water is absolutely necessary for optimal animal performance. . One-half to one day grazing period is recommended as "a rule of thumb" for dairy lactating cattle, while 3-7 days for non-lactating dairy cows and beef cow-calf cattle is recommended. One to three days for beef stockers.
The "Values" database built within PLMS for Virginia has projected yields by forage type and soils/geographic areas. Actual measured yields from past experience with hay crops can be used as the basis for planning estimates. The Forage Adaptation System (FORADS) software functions built within PLMS also offer a means for estimating future forage supply in states other than Virginia, based on soil type, forage type, and various other technical parameters. Soil survey data projections for forage yields from the NRCS County soil survey's soils database are also available. Since every season brings a different weather pattern and set of other problems, a producer should measure forage production in each paddock on a regular basis. This can be done using a pasture stick, rising plate meter, electronic probe, estimating by eye, or cutting a swath of known size and weighing it. The latter way is a good way to calibrate the eye if one remembers to look at the density, species composition, and stand height in relation to what was there during past cutting trials. These measurements need to continue during the season as growth rates go up and down.
A system of rotation among individual paddocks and/or strip-grazing units sets in place a dynamic system. The grazing animals quickly learn that when they are allowed to move they get to feast on fresh, nutritious forage. The key phrase in the first sentence is "when they are allowed to move…" i.e., they move themselves. They come to know that fresh, tasty forage awaits them and therefore they can't wait for the gate to be opened to move to a new stand. Once they become patterned to move themselves, the expectation of good things, conditions them to accept handling for other purposes as well, for example, deworming, weaning calves, artificial insemination, milking, etc. Thus, the benefits of a rotational grazing system extend beyond just better grazing.
There are three common mistakes made by farmers new to rotational grazing: 1) having an initial stocking density at a level too high over-utilizes forage present and weakens the stand; 2) an inadequate animal watering system; and 3) allowing cool season forage production to exceed animal needs or harvesting during the peak spring and fall growing seasons. Over-stocking is a common problem with conventional systems and can occur in rotational grazing system in the startup years. Stocking animals in excess of the plant and soil's capability to produce forages will not allow for efficient production. How many animals produced is not the single-most important issue a grazier should consider. Efficiency in production and sustainability should be the most important focus. Taking care of the resource base means stocking at levels that will allow maximum production and profitability. Profitable production won't occur without timely rotation of the grazing animals to keep the forage in a vegetative state to insure production of forages with highest nutritional value. Successful rotational grazing operations blend a mixture of management oversight, number of animals, and rotation length to fit the available acreage and paddock layout. In many cases, experience with rotational grazing has demonstrated that stocking numbers can often be expanded once a system has been established and the operator understands the variables he or she can use to serve their farm business objectives (for some producers, one of the highest costs resulting from conversion to rotational grazing is the cost of purchased animals to expand the herd to match the increased forage production that typically results from rotational systems).Historically water was something taken for granted because farms were laid out to take advantage of streams, rivers and ponds however, use of existing water systems are often inadequate and sometimes costly under rotational grazing conditions. Evidence continues to mount that livestock watered through open access to streams leads to more internal parasites, aborted fetuses veterinary medicine bills and lost production than on operations with clean water supplies provided via troughs and tanks. The volume of clean water available for a given herd is another important consideration, especially for dairies. You want to assure that water availability and quality are not a limiting factor. In addition, open access to streams degrades water quality for other uses downstream. Livestock will by preference choose alternative water supplies when available. By planning for and providing alternative water, the amount of sediment and other pollutants entering our streams will be reduced because the animals no longer have the need to linger around in the streams, springs or wetlands.
When temperature, soil water, nutrient and pH conditions are most favorable for cool season grasses to grow, in the spring and fall, forage production can get ahead of forage harvest with animals alone. Careful observation of grazing groups and forage production coupled with timely rotation of the animals is the mangers first recourse to help assure that what forage is available gets grazed when it is most valuable. Appropriate grazing pressure and rotation also helps maintain a stand of forage in its most productive and nutritionally valuable conditions. However, spikes of seasonal growth can out-strip a manager's ability to get animals on to all the paddocks when they need grazing. Stockpiling of fescue in the fall and the making of hay whenever possible are the main management tools for coping with the wonderful problem of having too much forage. If this wonderful problem tends to occur every year, then stocking rates are probably too low. But given the earlier discussion of coping with droughts, it must be kept in mind that having some excess forage production capacity can be a good thing.