Tips for Interpreting Forage Analysis

montana forage analysisBy Dr. Megan Van Emon, MSU Extension Beef Cattle Specialist

Having your hay and pasture quality analyzed prior to feeding or turnout is one of the most important and effective tools for cattle feeding management. Forage analysis allows for more precise feeding of supplements and other feedstuffs to meet requirements throughout the year. Forage analysis becomes especially important during drought and the possibility of limited forage intake while on grass. Therefore, accurately interpreting that forage analysis is crucial.

As Received Basis

These values represent the content of nutrients with the moisture included. Due to dilution, these values are lower than those in the dry matter basis column. These values can be converted to a dry matter basis by dividing the as received values by the percentage dry matter.

Dry Matter Basis

The values in this column give the nutrient profile after the water is removed. These values will be greater than those in the “as received” column. The removal of water allows for direct comparisons to be made between feed ingredients. The dry matter basis gives the best indication of the nutritive value of the feedstuff because we report animal requirements on a dry matter basis. Dry matter values can be converted to an as received basis by multiplying the dry matter value by the percentage dry matter.

Crude Protein (CP)

Labs measure the Nitrogen (N) content of the forage in order to estimate CP (% CP = % N × 6.25). Crude protein will include non-protein nitrogen and true protein. Crude protein provides the total protein within the forage and does not indicate if any heat damage has occurred, which could alter the availability of the protein.

Acid Detergent Fiber (ADF)

The acid detergent fiber encompasses the cellulose and lignin portions of the cell wall. This number is crucial in determining the ability of the animal to digest the forage. As ADF increases, forage digestibility decreases.

Neutral Detergent Fiber (NDF)

The NDF includes the ADF portion plus hemicellulose. The NDF value is important for determining forage dry matter intake. As NDF increases in the forage, dry matter intake decreases.

Total Digestible Nutrients (TDN)

This is the sum of the digestible fiber, protein, lipid, and carbohydrate components of the forage. In most laboratory analyses, TDN is usually calculated based on ADF and NDF and can vary by region and diet type. Typically, high quality forages range from 50 to 60% TDN and low quality forages range from 40 to 50% TDN. Using TDN in ration calculations is best for rations that are primarily forage. The net energy system should be used in diets that include high concentrations of grain because TDN tends to underestimate the feeding value of concentrate relative to forage.

Net Energy of Lactation (NEl), Net Energy of Maintenance (NEm), and Net Energy of Gain (NEg)

The Net Energy system accounts for the energy losses from digestion of feeds and forages. Net energy estimates the portion of energy in a forage that is useable to the animal to meet the needs of body maintenance and production. Net energy is partitioned into the net energy of maintenance (no body weight gain or loss), net energy of lactation (milk production), and net energy of gain (body weight gain). The net energy system should be used for diets containing high concentrations of concentrates. Net energy values are usually calculated from TDN values, which are calculated from ADF. Therefore, as ADF increases in the forage, net energy values will decrease.

Ash

This represents the total mineral content of the forage and typically ranges from 3 to 12% on a dry matter basis. Grains and concentrations usually contain range from 1 to 4% ash. Excessive amounts of ash indicate soil contamination.

Other analyses can also be conducted, such as nitrates, molds, yeasts, and mycotoxins, and individual minerals. These analyses are not typically included in a standard test and must be requested at an additional cost.

Forage Considerations For Fall Grazing

From “Pastures for Profit: A guide to rotational grazing”. University of Wisconsin Extension. 2014.

From “Pastures for Profit: A guide to rotational grazing”. University of Wisconsin
Extension. 2014.

By Dr. Emily Glunk, MSU Extension Forage Specialist and Assistant Professor

There are a lot of questions regarding whether or not it is safe to graze your fall pasture, and to what extent. Fall is a tricky time to manage grazing on pastures, as there is a lot going on with the plants below-ground, which we can’t always see. Grazing too hard in the fall has the potential to be very detrimental to forages, and should be managed accordingly.

So what all is happening right now in our forages? Cool-season grasses are trying to grow more new roots to replenish those that had been shed earlier in the summer. Right around June 21, the summer solstice, a lot of our introduced cool-season grasses shed their roots and begin to grow new ones, contributing to what is known as the “summer slump”. If you trek out to your pasture and dig up a couple plants, you should see quite a few new white roots and tillers forming, indicating a healthy plant and a healthy stand. Our legumes don’t shed their roots, as they have one well-defined taproot, but they are trying to store up enough carbohydrates to serve as any energy source for regrowth in the spring.

It is important that we don’t graze our pastures too heavily in the fall, as we can significantly impair the plants ability to store carbohydrates, or energy, which will help in the regrowth and recovery process. Plants go through a process called photosynthesis, which transforms sunlight into a usable energy source. The plants ultimately convert the sunlight (in the form of photons) to carbohydrates, which are stored in the roots or lower parts of the stem in some grasses. By grazing heavily, and removing most of the leaf area which is required for photosynthesis, we are limiting the plants ability to capture sunlight, and therefore create and store energy. This will be evidenced by slow growth in the spring, creating an opening for weed invasion, or if bad enough, winter kill over the winter.

So what can we do to manage these plants and prevent this from happening? Number one is to not graze very heavily in the fall. Allow those plants enough leaf area to continue photosynthesis, while not trying to use too much of their carbohydrate reserves for regrowth prior to winter. That is not to say don’t graze at all, but try to maintain an adequate stubble height for those forage species. You can contact myself or your local county agent to get species-specific recommendations. Number two, you can wait until after the plant has gone dormant to graze it down lower, because at this point the plant is no longer going through photosynthesis and accumulating carbohydrates, and it will no longer be using its energy reserves for regrowth before spring. You still should take care and be mindful of the impacts of hoof traffic on plant roots, especially in muddy conditions. While the plant may be healthy and have plenty of carbohydrates, if the animal physically injures the plant or its roots, this too can have a negative impact on regrowth ability and plant survival.

From the figure below, we see that carbohydrate reserves are at their lowest around internode elongation phase, a time when we have to be very careful in our management. This is when reserves are being used for primarily for plant regrowth and leaf production. Once there are enough leaves present, and the plant has begun the stem elongation phase, we see an accumulation of carbohydrates. The plant will be able to start storing carbohydrates at this point for regrowth in the spring. We want to make sure that the plant has the ability to store enough carbohydrates before a killing frost, so that we don’t see a problem in the spring.

Another thing that we see happening in the fall is the development of growing points for next spring’s growth. Those are the tillers that we can hopefully see when we dig up some plants. Old tillers may appear brown and dead, but they still serve an important role to the plant. They are a form of stored nutrients, as well as provide protection to the new, developing tillers. We also want to avoid allowing animals the ability to graze off these new tillers, which will be helped by leaving adequate stubble height. Another benefit of leaving some stubble in the field is that it increases the amount of snow that is caught, insulating the soil, and decreases the potential for ice sheeting. This too will help increase plant survivability over the winter.

For any questions or forage recommendations, contact Dr. Emily Glunk at emily.glunk@montana.edu or 406-994-5688. or contact your local county extension agent.

Range Ruminations: Are Range Grasses Vulnerable to Grazing during Early Fall?

Jeff Mosley MSU ExtensionIn ranching it’s often necessary to spend money to make money. Funds from savings accounts or operating loans are spent to purchase inputs such as vaccine, seed, fertilizer, or feed. These inputs help fuel the engine that hopefully returns enough income to replenish the savings account or repay the bank, and also cover enough living expenses that you can afford to play the game again next year.

Range grasses often play a similar game during early autumn. Most years range grasses go dormant in late summer when days get hot and soils get dry. If more mild temperatures return in September and October accompanied by rain or early wet snow, grasses respond by breaking summer dormancy. To initiate this new growth grasses must draw upon stored energy reserves in their roots and stem bases. In other words, grasses must spend some of their savings to kick-start the new growth in early fall.

After the new leaves reach one-third to one-half their mature size they produce enough energy via photosynthesis to fuel their own growth and begin replenishing the plant’s energy reserves (i.e., begin repaying the bank). With enough time and leaf area, grasses are able to repay the bank, cover their living expenses, and can afford to play the game again next year. However, if grazing during early fall removes too much of this new leaf area before plants replenish their reserves, range grasses enter winter in a weakened condition, may not survive winter, won’t produce as much forage next spring, and won’t compete as well against weeds next year.

Similar situations occur in hay fields cut too late in the season, prompting recommendations that the last cutting of hay should occur at least three weeks before the killing frost to enable plants to recover before winter, or swathing should wait until later in the season when cold temperatures prevent plants from expending stored reserves to fuel regrowth.

Few ranches, however, are able to stop grazing three weeks before the first killing frost in order to manage their livestock grazing enterprise as they do their hay enterprise. One approach that can help is to move livestock from rangelands to seeded pastures comprised of grass species that better tolerate grazing during early fall. If this is not feasible, another approach is to reduce grazing intensity during early fall. Grazing lightly during early fall (i.e., leaving more than three to four inches of residual forage height after grazing) provides grasses more leaf area for photosynthesis to produce energy that can restore the reserves used to break summer dormancy. Rotational grazing also works well during fall. The first grazing period can be brief during early fall when grasses are growing, followed by heavier grazing during late fall when it’s too cold for plants to initiate regrowth after grazing.

In summary, close grazing of range grasses during early fall can be very damaging when growing conditions have enabled grasses to break summer dormancy. Avoiding heavy grazing during these times will keep grasses healthy going into winter and help grasses produce more forage next spring. Happy ruminating.

In ranching it’s often necessary to spend money to make money. Funds from savings accounts or operating loans are spent to purchase inputs such as vaccine, seed, fertilizer, or feed. These inputs help fuel the engine that hopefully returns enough income to replenish the savings account or repay the bank, and also cover enough living expenses that you can afford to play the game again next year.

Range grasses often play a similar game during early autumn. Most years range grasses go dormant in late summer when days get hot and soils get dry. If more mild temperatures return in September and October accompanied by rain or early wet snow, grasses respond by breaking summer dormancy. To initiate this new growth grasses must draw upon stored energy reserves in their roots and stem bases. In other words, grasses must spend some of their savings to kick-start the new growth in early fall.

After the new leaves reach one-third to one-half their mature size they produce enough energy via photosynthesis to fuel their own growth and begin replenishing the plant’s energy reserves (i.e., begin repaying the bank). With enough time and leaf area, grasses are able to repay the bank, cover their living expenses, and can afford to play the game again next year. However, if grazing during early fall removes too much of this new leaf area before plants replenish their reserves, range grasses enter winter in a weakened condition, may not survive winter, won’t produce as much forage next spring, and won’t compete as well against weeds next year.

Similar situations occur in hay fields cut too late in the season, prompting recommendations that the last cutting of hay should occur at least three weeks before the killing frost to enable plants to recover before winter, or swathing should wait until later in the season when cold temperatures prevent plants from expending stored reserves to fuel regrowth.

Few ranches, however, are able to stop grazing three weeks before the first killing frost in order to manage their livestock grazing enterprise as they do their hay enterprise. One approach that can help is to move livestock from rangelands to seeded pastures comprised of grass species that better tolerate grazing during early fall. If this is not feasible, another approach is to reduce grazing intensity during early fall. Grazing lightly during early fall (i.e., leaving more than three to four inches of residual forage height after grazing) provides grasses more leaf area for photosynthesis to produce energy that can restore the reserves used to break summer dormancy. Rotational grazing also works well during fall. The first grazing period can be brief during early fall when grasses are growing, followed by heavier grazing during late fall when it’s too cold for plants to initiate regrowth after grazing.

In summary, close grazing of range grasses during early fall can be very damaging when growing conditions have enabled grasses to break summer dormancy. Avoiding heavy grazing during these times will keep grasses healthy going into winter and help grasses produce more forage next spring. Happy ruminating.

MSU to host Agricultural Economics Outlook Conference

montana state extension logo

BOZEMAN – Montana State University’s Department of Agricultural Economics and Economics and MSU Extension will host the 9th annual Agricultural Economics Outlook Conference on Nov. 6.

This year’s conference, “Montana Agriculture: Global Trade to Local Foods,” will run from 9:30 a.m. to 1:30 p.m. in the Procrastinator Theater in MSU’s Strand Union Building.

The conference’s keynote speaker is Colin Carter, professor of agricultural and resource economics at the University of California Davis and director of the Giannini Foundation of Agricultural Economics. Carter’s research is focused on international trade, futures and commodity markets, and he has published more than 130 research papers and authored more than 15 books.

“Dr. Colin Carter is one of the world’s leading experts on international agricultural trade and trade policy issues,” said Vincent Smith, professor of economics in the MSU Department of Agricultural Economics and Economics. “He works extensively with both U.S. and international government and non-governmental agencies and interest groups on trade related disputes, and his academic research has been widely recognized for its insights and importance.”

Carter will address agricultural trade and the Trans-Pacific Strategic Economic Partnership Agreement (TPP), a proposed regional free trade agreement currently being negotiated among the United States, Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore and Vietnam. TPP is a trade policy of President Obama meant to expand American goods and services exports to new markets while setting high standards of global trade, according to the Office of the United States Trade Representative. The TPP has important implications for Montana’s agricultural exports, according to Smith.

The conference, which is part of MSU’s Celebrate Agriculture weekend, is also designed to provide Montana agricultural, business leaders, agricultural bankers, producers and others in agriculture with quality, unbiased information about issues facing Montana agriculture.

“The outlook conference is an outstanding example of MSU’s commitment to the land-grant mission of bringing high-quality, relevant research findings to the citizens of Montana,” said Jeff Bader, director of MSU Extension. “The event brings important insights about the current standing and future of agriculture from a research perspective, which is always appreciated by our stakeholders.”

During the morning session of the conference, MSU agricultural economics professors will share their expertise on aspects of Montana’s agricultural industry. Speakers include Kate Fuller, who will discuss the status of Montana agriculture; Joe Janzen, who will discuss marketing Montana pulse crops; and Eric Belasco, who will discuss cattle market fundamentals and prices. Registration is $25 for the morning session and lunch. Those who register by Wednesday, Oct. 28, will receive a free parking pass. To register, please visit www.ampc.montana.edu/fallconference/index.html.

Following lunch at 1:45 p.m., two in-depth breakout sessions will be offered. The first session will focus on innovations in price risk management from MSU economics professors Gary Brester, Janzen, Joe Atwood and Belasco. The second session will focus on producer and consumer relationships in local food markets and will feature Dawn Thilmany McFadden, professor of agribusiness at Colorado State University, and MSU Agricultural Economics Professor George Haynes. Several local food businesses will also share their perspective with attendees. Registration is not required for the breakout sessions.

For a full schedule of events and speakers at the conference, please visit http://www.ampc.montana.edu/fallconference/index.html.

A full schedule of events for the Celebrate Agriculture weekend event is available at: http://ag.montana.edu/excellence/agappreciation.htm.

The Importance of Water Quality in Livestock Production

megan van emon msu extension beef specialistBy Dr. Megan Van Emon, MSU Extension Beef Cattle Specialist

Water is the most essential nutrient for livestock production and is needed for numerous processes, such as the regulation of body temperature, growth, digestion, reproduction, metabolism, lubrication of joints, excretion, eyesight, etc. Water is also an excellent solvent for amino acids, minerals, glucose, vitamins, and metabolic waste.

Water requirements are influenced by a number of factors, including gestation, lactation, rate and composition of gain, type of diet, activity, environmental temperature, and feed intake. The intake of water from feeds plus the ad libitum consumption of free water is the equivalent of the water requirements in livestock. Ad libitum access to clean, fresh water is essential to maintaining feed intake in livestock. According to the NRC (1996), a wintering 1100 pound gestating cow needs to consume between 6 gallons at 40°F and 9 gallons at 70°F of water per day and the requirements double for a lactating cow. However, the requirements do not take in to account the distance cows must travel to the water source.

The water provided to livestock needs to be good quality to maintain production. Water quality may be altered by contaminants, such as mineral salts, toxins, heavy metals, microbial loads, debris, and agricultural practices. Most contaminants will reduce water intake, which results in a reduction in feed intake and a loss of production. However, if the water or feed contains increased salt, water intake will increase as the animal attempts to eliminate the excess sodium. Total dissolved solids (TDS) are measured to determine the saltiness of the water. Table 1 describes the recommendations and effects of increasing concentrations of TDS in the water.

Total Dissolved Solids Water QualityWater with high concentrations of TDS, may have high concentrations of nitrates and/or sulfates. High sulfate concentrations in water can lead to polioencephalomalacia (polio).  High sulfate water tastes bitter and water intake may be reduced. High concentrations of sulfate may also cause a reduction in copper availability in livestock, which can lead to copper deficiency. Producers should be aware of water sulfate concentrations when feeding high sulfur feedstuffs, such as distillers grains or corn gluten feed, and feeds containing high concentrations of molybdenum.  If livestock are consuming high sulfate water, additional copper supplementation may need to be considered.

Similar to nitrates in forages, water with high nitrate concentrations can also be toxic. Nitrate from the water is converted to nitrite within the rumen, which can be toxic by decreasing the oxygen-carrying capacity of hemoglobin. Producers should especially be aware of water nitrate concentrations when feeding forages with high nitrate concentrations.

Other contaminants include bacteria, which can be toxic to livestock. High bacteria concentrations can cause infertility, foot rot, low milk production, and other reproductive problems. Stagnant water that is contaminated with manure and other contaminants can develop blue-green algae, which may be toxic to livestock. It is crucial to maintain a clean, fresh water supply to maintain health and performance of livestock.

Researchers seek information from Montana cattle producers and veterinarians

5L Ranch red angus calf warm in strawResearchers from Montana State University Extension and Washington State University are asking Montana beef cattle producers and veterinarians to participate in a voluntary online survey to learn more about a novel form of neonatal calf pneumonia found in Montana.

Rachel Endecott, MSU Extension beef specialist, and colleagues at WSU said that a unique form of neonatal calf pneumonia has been diagnosed in several Montana beef herds over the last 6-8 years. The majority of affected calves are relatively normal at birth, but go on to develop signs of pneumonia within the first 1-4 days of life and die due to respiratory failure, Endecott said. A small proportion of calves with this problem are born dead, she added.

Samples from these animals have been submitted to veterinary diagnostic laboratories where they were diagnosed with pneumonia, but a specific cause was not identified, according to Endecott. Researchers believe that affected herds typically experience a three to five percent (or greater) increase in calf losses associated with this problem the first year it is recognized, and 0.5-1.0 percent greater calf losses in subsequent calving years. Endecott said more information is needed to better understand the problem.

MSU Extension and WSU researchers will use the data collected through these surveys to help investigate the prevalence of this unique form of neonatal calf pneumonia in Montana and better estimate its impact on producers, Endecott said. The survey results will then be used to help guide a study to determine the cause of the disease and develop a treatment and/or management strategy to prevent calf losses.

Endecott noted the survey should take only a couple of minutes.

“We appreciate the involvement of all beef cattle producers and veterinarians in helping us better understand this illness so that we can manage it appropriately,” Endecott said.

The surveys can be found online at http://animalrangeextension.montana.edu/beef.

Contact: Rachel Endecott, (406) 994-3747 or Rachel.endecott@montana.edu

Watch for Nitrate Toxicity in Forages

Emily Glunk Montana State Forage ExtensionBy Dr. Emily Glunk, MSU Extension Forage Specialist

Nitrate toxicity is a problem that many producers have to deal with in Montana. Particularly this year, with a large amount of cereal grains being harvested for hay, it is something that should be kept in the back of your mind at harvest and feedout.

Nitrate toxicity is an accumulation of nitrates in the plant. Typically, the lowest third of the plant stem will have the highest level of nitrates. Why are these high levels of nitrates toxic to the animal? When the animal consumes a large amount of nitrates, it is unable to be completely converted to microbial protein in the rumen. Instead, an intermediate in the conversion of nitrate to protein, nitrite, will be transported to the small intestines and absorbed into the blood system. This is where the real problem starts. Nitrite will bind to hemoglobin, the oxygen carrying component of blood, to form methemoglobin. Methemoglobin is unable to supply oxygen to the rest of the body, and the animal will start to become stressed.

Acute toxicity signs include things such as labored breathing, muscle tremors, weakness, and ultimately death. Animals that have chronic toxicity, or have been consuming high levels over a long period of time, will have decreased production, rough hair coat, and reproductive issues, among others.

What is happening in the plant to cause increased nitrate levels? Nitrate accumulation can occur for many reasons: environmental stress such as drought or hail, excessive application of Nitrogen fertilizer, deficiency of other nutrients such as K and S, shade, prolonged cool temperatures, the list goes on. Another important factor is plant species. Cereal grains tend to accumulate nitrates more-so than cool-season forages. Oats have been found to be the most prone to accumulating toxic nitrate levels, with wheat and barley a little less likely. Warm-season grasses such as sorghums and sudangrasses also have potential to accumulate nitrates.

If any of these situations occurs, or the plant becomes stressed, the likelihood of accumulating toxic levels is increased. In most of these situations, photosynthesis is inhibited or decreased, which supplies the Carbon, or energy, that is required to convert the nitrate to plant protein. Without the required Carbon, similar to in the rumen, the nitrate will not be converted to the final, desirable product, protein.

How can we decrease the chances of nitrate toxicity? There are a few things that we can watch out for. Always make sure that you are monitoring soil nutrient levels, and try to apply fertilizer according to soil and plant needs. Make sure to not overlook other soil nutrients, like Potassium and Sulfur, as they can have a significant impact on Nitrate uptake and accumulation in plants. Take care when applying and handling any N fertilizer, so that large amounts don’t get spilled or over-applied in one particular area. When harvesting, wait for several days after a drought-ending rain before harvesting, or after a hail event.

If you suspect your forages may be “hot”, I would advise to test them before harvesting or feed out. Your local county agent has an in-field test called the Nitrate QuikTest, which allows them to qualitatively estimate whether your forages may have toxic levels or not. This test does not provide a level of nitrate, but rather advises you as to whether there may be toxic levels or not based on what color the testing solution turns, and how rapidly that change occurs. We are also looking to test some in-field quantitative nitrate testing kits, to evaluate whether these commercially available products are accurate and reliable ways to determine nitrate levels in standing forage.

If your forage tests hot, or may be marginal, I always recommend sending it in to a lab for a quantitative nitrate analysis. This will help you determine if you need to dilute the hay in the ration by feeding it with a low-nitrate forage, or if it is safe to feed. Toxic levels also depend on production stage of the animal, with young and pregnant animals having low tolerance to nitrates, as depicted in the table below. You can contact your county agent, or myself, to help develop a ration that is suitable to feed to your animals.

If you have any questions or comments, please contact Dr. Emily Glunk at 406.994.5688 or at emily.glunk@montana.edu. For more detailed information on nitrate toxicity, you can also reference the Montana Extension MontGuide “Nitrate Toxicity of Montana Forages” (MT200205Ag).

Range Ruminations: Is “Take Half, Leave Half” a Good Way to Calculate Stocking Rate?

Jeff Mosley MSU ExtensionBy Dr. Jeff Mosley, MSU Extension Range Management Specialist

Former eastern Montana rancher and Past President of the Society for Range Management Dan Fulton once wrote, “Range, and particularly Great Plains range, cannot be rationally managed on the basis of range carrying capacity surveys. The only way to know for sure how many cows can run on it is by grazing cows on it.” Fulton’s statement reminds us that grazing management is a circle. We begin by observing the land and animals, and then make a plan based on what we have observed. Next we implement the plan and observe how well the plan is working. Based on what we observe, we make adjustments, observe again, make more adjustments, and so on. Grazing capacity surveys and stocking rate calculations can provide helpful estimates of an area’s sustainable stocking rate, and these ballpark estimates can be used to develop a plan, but they are not the final answer.

Stocking rate calculations include an estimate of proper utilization, and historically in Montana, the concept of “take half, leave half” (i.e., 50% utilization) has often been used. This approach recognizes that to remain healthy, grass plants must replace about 1/3 of their roots each year, and grass plants stop growing roots when more than 50% of their current year’s foliage is removed during the growing season. I believe 50% utilization is an appropriate threshold for growing-season grazing wherever most forage plants have similar palatability that results in relatively homogeneous levels of grazing among plants. However, I believe stocking rate calculations using 50% utilization provide stocking rates that are unnecessarily conservative in some situations and stocking rates that are unsustainable in other circumstances.

Situation #1. Grass plant response to grazing definitely depends on how much foliage is removed during the growing season, but plant response also depends on when the grazing occurs. Plants grazed later in the growing season can sustain 60-70% utilization if they have already had sufficient time earlier in the growing season to grow foliage, grow roots, and replenish energy reserves. Plants can sustain 80% utilization if grazing occurs when foliage and roots are not growing during winter plant dormancy.

Situation #2. Late spring/early summer is generally the time when grasses are most vulnerable to defoliation, but plant response to grazing also depends on how often grazing occurs. Grass plant health declines when 50% defoliation during late spring/early summer occurs for more than two successive years. Two years in a row is okay, but more than two consecutive years of moderate grazing during late spring/early summer is not sustainable. Some form of rotational grazing is necessary when moderate use occurs during late spring/early summer. A moderately stocked rotational grazing system that provides rest during late spring/early summer once every three years averages 33% utilization across the three years (50% use in Year 1 + 50% in Year 2 + 0% in Year 3 / 3 years = 33%). In this situation, stocking rate calculations should be based on 33% rather than 50% utilization.

Situation #3. Typically when utilization averages 50% on bunchgrass rangeland, many or most bunchgrasses have received heavy use (e.g., 70% utilization), a few bunchgrasses have received light use (e.g., 30% utilization), and a few bunchgrasses have remained ungrazed. Preferred bunchgrasses grazed during the growing season at 70% utilization are unable to grow roots and replenish energy reserves. Thus, some form of rotational grazing is necessary on bunchgrass rangeland grazed moderately during the growing season.

A 2-pasture rotational grazing system that provides growing season rest every other year averages 35% utilization for the preferred bunchgrasses over the 2-year period (70% use in Year 1 + 0% use in Year 2 = 35% utilization), which is safely below the 50% threshold. In this 2-pasture system, stocking rate calculations should be based on 25% utilization rather than 50% utilization (i.e., 50% in Year 1 + 0% in Year 2 / 2 years = 25% utilization).

Similarly, a 3-pasture rotational grazing system that provides growing season rest one year out of every three averages 47% utilization during the growing season for the preferred bunchgrasses over the 3-year period (70% use in Year 1 + 70% use in Year 2 + 0% utilization in Year 3 / 3 years = 47% utilization), again safely below the 50% utilization threshold. In this 3-pasture system, stocking rate calculations should be based on 33% rather than 50% utilization (i.e., 50% in Years 1 and 2 and 0% in Year 3, averaging 33% across the three years). This example also illustrates the incentive for 3-pasture versus 2-pasture rotational grazing systems. The 3-pasture system can be sustainably stocked 32% heavier than the 2-pasture system (i.e., 33% utilization – 25% utilization / 25% utilization = 32% increase).

In summary, stocking rate calculations can help inform grazing management planning and decision-making, but an area’s sustainable stocking rate can only be determined by making your best guess, implementing your plan, and then making adjustments as needed based on how the land and animals respond. Going forward, I suggest that initial stocking rate estimates will be more accurate and helpful when stocking rate calculations adjust the take half, leave half approach (i.e., 50% utilization) when needed, accounting for the time of year that grazing occurs, how often grazing occurs among years, and how much utilization levels vary among individual forage plants. Happy ruminating.

MSU Students Place Second in Regional Animal Science Competition

Rachel Endecott, Montana State University Extension Beef Cattle SpecialistBy Dr. Rachel Endecott, MSU Extension Beef Cattle Specialist

Happy summer! This month, I’m proud to feature this press release from MSU News Service about the MSU Academic Quadrathlon Team.

BOZEMAN – Four students from Montana State University’s Department of Animal and Range Sciences in the College of Agriculture placed second in the Western Region Academic Quadrathlon, held June 22-23 in Ruidoso, N.M.

The regional contest was held in conjunction with the 2015 Western Section American Society of Animal Science meetings, hosted by New Mexico State University. The MSU team competed with four other universities in the western region, including California State University-Chico, New Mexico State University, Oregon State University and Utah State University.

L to R, Elena Combs, Alyson Hicks-Lynch, Bailey Engle, Emily Griswold

L to R, Elena Combs, Alyson Hicks-Lynch, Bailey Engle, Emily Griswold

Elena Combs of Missoula, Bailey Engle of Big Timber, Emily Griswold of Millerstown, Pa., and Alyson Hicks-Lynch of Hood River, Ore. competed in a four-part contest that consisted of a comprehensive written exam, impromptu oral presentation, hands-on lab practicum and a double-elimination quiz bowl tournament.

“Elena, Bailey, Emily and Alyson did a spectacular job representing MSU at the contest,” said Rachel Endecott, team adviser and MSU beef cattle extension specialist. “I’m extremely proud of them and their hard work.”

All four students graduated in May from the department. Endecott said Combs has been accepted into the Washington, Idaho, Montana and Utah (WIMU) Regional Program in Veterinary Medicine and will complete her first year of veterinary school in Bozeman this fall. Engle will begin a five-year Ph.D. program in breeding and genetics at Texas A&M University. Griswold works as a veterinary technician at Sorenson Veterinary Clinic and is applying for vet school this year. Hicks-Lynch will begin a master’s degree program at Oregon State University in range management and ruminant nutrition this fall.

How Much Seed Should I Plant?

Emily Glunk Montana State Forage ExtensionDr. Emily Glunk, Extension Forage Specialist and Dr. Jessica Torrion, Crop Physiologist

Depending on who you ask, you may get a wide range in how much seed you should be planting per acre. There are a lot of factors to consider, but in my experience, there are many producers throughout the nation that are spending more money, and putting more seed in the ground, than is necessary. There are some situations where it may be desirable to increase your seeding rate, say in an irrigated field versus a dryland field, if the seedbed is less than optimal, or where the seeding depth is hard to get completely accurate due to rough terrain.

It is important to remember that not every seed that is dropped will result in a plant. This is where your seed tag can be helpful. On the seed tag, it should list a germination percentage. This is an estimate of how many of the seeds in that bag are actually viable and able to germinate. Also important on the tag is the list of other potential “contaminants”, such as weed seeds (which will be listed as a percentage), other seed, and inert matter. The percentage of each of these should be minimal.

Another factor that can decrease germination rates is the seeding rate itself. Research from other states has found an estimated 45% mortality rate in the first year for alfalfa planted at 10 pounds per acre, and a 60-70% mortality rate for seeding rates over 20 pounds/ acre. So having a high seeding rate can actually be detrimental to your seed!

The important thing to start with is how many plants do you need per square foot? This will then help you to calculate how many pounds of seed you will need per acre. There are many tables available which provide estimates of desired number of plants per square foot. Alfalfa, for example, 30 plants per square foot is an optimal target plant population. Now, that does not mean that every year thereafter we are expecting to have 30 plants per square foot. Competition amongst plants for nutrients, canopy space, and water will decrease that number to less than 20 plants per square foot just after the stand’s first winter.

There are approximately 199,000 alfalfa seeds in one pound of seed, which equates to about 5 seeds per square foot if that pound were spread evenly over an entire acre. So, to figure out how many seeds you are planting an acre for alfalfa, take your seeding rate (in pounds per acre), and multiply by 5. If you were planting at 8 pounds of Pure Live Seed (PLS, we’ll cover that later), that means that you are putting approximately 40 seeds per square foot. Will you see 40 plants per square foot? Likely not. Seeds will also compete with one another, just like germinated plants, for light, moisture, and nutrients, and the most competitive plants will survive.

How can we figure out then how many pounds of seed we need to put in the ground? Let’s first get back to that thing I mentioned before, pure live seed or PLS. This is the amount of seed that has the ability to germinate, and is what we should be using when we are considering how much to plant. To figure this out, we simply use the information provided on the seed tag.

seed tag how much to plant

Step 1. We first want to figure out the purity of the seed in the bag. To determine this, we simply subtract the percent other crop, percent innert matter, and percent weed seed from 100.

For this tag, it would look like:

100-.11-.69-.18= 99.02% purity.

As you will notice, this number is already on the seed tag, however, not all seed tags will list this.

Step 2. Next, we need to determine PLS by multiplying that percent purity by the percent germination, and then by 100 as a conversion factor. Also remember to convert your percent’s to decimals, so 99.02% would be .9902.

.9902 (% purity) * .93 (% germination) * 100= 92.08% PLS

You will notice the percent germination was not actually listed on the bag, but we were able to figure it out by dividing the PLS weight (2.79 pounds) by the bulk weight (3 pounds).

Step 3. To figure out how many pounds of PLS we would need to get our desired establishment rates with this bag, we would then divide the recommended seeding rate (usually listed on the tag, for this we’ll use 10 pounds).

10/ .9208 (PLS in decimal form)= 10.9 pounds required at seeding

For this particular bag, there was very high germination rates and low levels of foreign seed, so we didn’t have to increase our seeding rate that much to get the desired number of seeds in the ground. This may not always be the case, which is why knowing how to figure out your PLS rate is extremely important to attain adequate stand establishment.

One final note, just like any other crops, seed size can influence the number of seeds per pound. Bigger seeds means less seeds per pound, and smaller seeds mean more seeds per pound. This is something to be mindful of, and to ask of your seed dealer, when purchasing seed.

For a list of recommended seeding rates, contact myself, Dr. Jessica Torrion, or your local county extension agent. There are also numerous publications available with seeding rate recommendations, such as the “Dryland Pastures in Montana and Wyoming”.

If you have any questions or concerns, please feel free to contact Dr. Emily Glunk at 406-994-5688 or emily.glunk@montana.edu, or Dr. Jessica Torrion at jessica.torrion@montana.edu