Grazing: Frequently Asked Questions

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1. How does reed canary grass work in a rotational grazing system?

Morrical: Reed canary grass is an excellent cool season grass in terms of productivity. Most of us are familiar with RCG that is abundant in wet, low-lying areas. Unimproved reed canary grass contains an alkaloid that grazing animals find unpalatable. Under rotational grazing one can put more pressure on the reed canary grass and force cattle to consume RCG. The other benefit of RCG is its excellent productivity.

However, due to this excellent growth, more rapid and intensive grazing is required. Best management practices for RCG would be to use it as a single grass in paddocks which eliminates animal selectivity. Secondly, it may require more fertility to maintain its high growth potential.


2. I have an increasing amount of tall fescue invading my pasture. How do I get rid of it?

Barnhart: Tall fescue is a perennial forage grass that is persistent on a wide array of site conditions and under variable grazing managements. It is responsive to fertilizer management. It forms a tough sod. And, tall fescue is often the grass-of-choice when stockpiling for fall or winger grazing. While it has many desirable traits, much of the tall fescue found in Iowa pastures harbors an internal fungus (an endophyte) that can cause undesirable production and physiological concerns in grazing livestock.

Before setting out to get rid of the tall fescue, honestly assess whether it is causing an economic problem now. Many producers are using management practices that have allowed them to co-exist successfully with the fescue for many years. Some of their more practical management practices include: clipping of pastures (grass seedheads) in mid- to late-spring; diluting the fescue by interseeding or frostseeding legumes into the pasture; and moving the grazing animals to a non-fescue forage during the hottest weeks of the summer if possible.

If you feel that you must get rid of the tall fescue, our current recommendations call for a multi-year approach. Some of the fungus-infected seed that has shattered during the past year will likely germinate within the next year, producing fungus- infected, volunteer tall fescue seedlings. This will be a problem if the old stand is simply tilled or herbicide-killed and re-seeded to another forage mixture.

Fescue renovation managements are designed around the premise that fescue seed in the soil "seedbank," more than a year old, is generally considered to be free of the fungus infection, and that volunteer seedlings form 2 (or more)-year old seed will be free of the endophyte fungus. Two alternative management practices are then recommended. 1) plan to clip the fescue seedheads for a year or two before renovating the old pasture; spry the pasture with a systemic, grass control herbicide in early fall, and reseed the following spring; or, 2) eliminate the infected pasture growth with a systemic, grass control herbicide in the fall, plant an intervening row crop or annual forage crop for a year or more, re-spray to kill any infected volunteer fescue seedlings, and then reseed the pasture.


3. We are planning to expand our cow herd. What is the first thing we should do to provide more pasture? Add (rent or buy) additional acres, add legumes and/or fertilizer to increase production? Increase the number of paddocks?

Morrical: As one contemplates adding cows, the first option I would evaluate is increasing the grazing management by more paddocks. Rotational grazing will result in 25-50% increase in forage productivity. Adding cows also means more winter feed so that portion of the operation also needs evaluated. The first one needs to do to grow more forage is planting fence posts for additional cross fencing to improve grazing management.

The next step to grow more grass would be to evaluate the fertility program for pasture acres. Initially this would involve soil testing to determine N P and K levels. Adding P & K as determined by soils test would be an additional way of growing more legumes and grass. Fertility management changes could also include mid to late summer nitrogen applications. Operations with excess spring forage may benefit from delayed nitrogen applications. For example applying 50 pounds on N or split application in early spring and mid June or 50 pounds early June and early August. These later applications will help maintain more summer growth of cool season grasses.

Multiple options exist for growing more forage. Producers should contact field livestock specialist to develop various options using the forage planner. This software package helps access different scenarios very rapidly and identifies potential shortages in forage supply. It may be possible to run more cows if acres dedicated to hay can be shifted to grazing. Traditionally, we think more land for more grass, however depending on current sophistication of the grazing system, inputs into existing systems might be cheaper than land acquisition.


4. I have an increasing number of winter annuals - mustards - growing in my paddocks, what should I do to eliminate them? Why are they coming in?

Barnhart: Winter annuals are plant species that germinate in summer or autumn, grow vegetatively through the fall months, overwinter as dormant plants, produces seedheads or flowers and seed in the spring of the following year and then die. In addition to the winter mustards, other common winter annual weeds frequently found in pastures are downy brome (cheatgrass) and wild carrot. These weeds are "opportunists." They often get started in areas of the pasture with weak or thin sod cover; along paths and around water sites; and following seasons when grazing was severe.

Managing pastures to provide thick, productive stands through species
selection, fertility and grazing management is the most effective way to manage winter annual weeds. Livestock will eat many of these weeds in early spring, before seed formation. Clipping in the spring to prevent the development and spread is recommended. Broadleaf winter annual weeds are often controlled well in grass-only pastures by labeled pasture herbicides. Their control with herbicides in mixed grass/legume pastures with herbicides is limited to mostly spot spraying of heavily infested areas, with associated loss of desirable legumes. With some broadleaf herbicides, replanting of legumes must be delayed. Herbicide choices for controlling winter annual grasses are limited. With severe infestations of winter annual grasses, destruction of the infested stand and reseeding may be the only option.


5. Do I need to allow my paddocks a "rest" period in the fall, or can I rotate up until a freeze in late October?

Barnhart: Pasture plants don’t need a rest period in the fall, but they will benefit from it. They maintain "physiological vigor" when adequate leaf area is present and they can maintain good photosynthesis rates. Close, frequent grazing management is most stressful. Rotationally grazed pasture plants maintain their vigor through regular rest periods. They recover even more quickly when moderate residual leaf area left following each grazing cycle. Perennial pasture grasses and legumes "prepare" for winter dormancy with the accumulation of sugars and nitrogen compounds in their roots and lower stem bases, and, they undergo other internal physiological changes during shortening days and cooling nights. Pasture plants attain the greatest winterhardiness and vigor when they get 4 to 5 weeks of uninterrupted growth (rest) during late September and October. If they enter dormancy at a high level of vigor, they overwinter well and recover more quickly the following spring. While these pasture grasses will generally survive the winter without a fall rest period, their recovery is slower the following spring.


6. What type of increased production response from pastures should I expect by interseeding a legume, such as red clover, in bluegrass pastures?

Barnhart: The inclusion of legumes into grass-based pastures provides several advantages. Nutritive quality of legumes gives a slight boost to animal performance. The nitrogen contribution from the legume to the associated grasses can be as much as the same growth stimulus provided by 30 to 50 lbs / Ac of fertilizer nitrogen. And, a lesser noticed benefit is a better distribution of pasture growth through the summer months than is seen in most grass-dominant pastures. The degree of total benefit will be relative to the percentage of legume in the improved pasture. If the legume proportion is 35 to 40% or more, production per acre can be nearly doubled; with lesser legume content, proportionally lesser benefits.

Keeping the improved legume component should be an important management goal for the improved pasture. Maintain adequate fertility to support legume growth (lime, phosphorus and potassium), and begin a pasture rotation management to allow for adequate rest/recovery periods for the legumes (and grasses).


7. I have a bluegrass pasture with some thistles and some brush. I want to add a legume, and use a rotational grazing system. What do I do first?

Barnhart: Whether interseeding legumes into a grass pasture, or frostseeding, preparatory steps include: controlling weeds and brush before planting the legume; correcting needed soil pH and fertility; and reducing the vigor of the associated grasses with herbicides or closer-than-normally-recommended grazing. Follow-up management steps include: clipping and/or grazing during the establishment year to allow adequate light availability to the establishing seedings; and implementing grazing management and fertility programs that maintain the newly established legume component. Either adding the legume or implementing rotational grazing can come next, but many producers who begin to rotate pastures find that legumes will "volunteer" in their pasture relatively soon. So based on this, you might consider implementing the rotation next, and then see if you need to add legumes.


8. What is the ideal number of paddocks?

Morrical: The ideal number of paddocks in a system is difficult since there is no ideal number. In terms of rest and recovery, six paddocks may be enough.

Generally, six paddocks means cows would rotate every three to six days. Cows nutrient requirements are not that great and forage quality is not as critical compared to stockers or dairy cows. In reality, two paddocks are much better than continuous grazing. Four to five paddocks with weekly rotations is a pretty typical cow pasture grazing system. As one gets to five or more paddocks it makes it possible to hay a portion of the paddocks during the early portion of the grazing season. More paddocks means more flexibility and more control. Most operators start with four and quickly go to more once they observe what rest and recovery does for pasture productivity.


9. I have an alfalfa grass pasture. Can I graze this without bloat problems? Do the bloat-guard-type products work?

Morrical: Bloat on alfalfa grass pastures are a risk. The risk is directly proportional to amount of legume in the systems. Generally, if there is less than 50-percent legume in the pasture mix, bloat risk is minimal. The more mature the alfalfa is before grazing also lowers the bloat risk. Bloat guard products work to reduce the incidence of bloat. Uniform consumption via blocks is difficult to achieve and low intake by cows or day to day variation may mean some cows still bloat. The only legume which does not cause bloat is birdsfoot trefoil.


10. How many acres of pasture do I need to carry a cow-calf pair through the grazing season?

Morrical: Beef cow SPA records indicate that on an average, it takes 2.5 acres per cow. This data is for the growing season acres. Huge variation exists for the acres needed depending on soil fertility, plant species and grazing management. Additionally, the length of the grazing season has an input as well on how many acres are required. For instance grazing from May 1 to Oct. 1 takes less acres than April 1 to Dec. 31.


11. When comparing warm season native grasses and cool season grasses with legumes, which gives the most production during summer months, which gives the most production in overall grazing season?

Barnhart: As the saying goes, you are comparing apples and oranges. When looking only at the summer months (late June through Aug ), well-managed (fertility) warm-season grasses will have a great physiological advantage and produce more standing forage than a cool-season grass plus legume. And, it is as likely that the warm-season grass will produce more total standing forage over the growing season. An exception might be an alfalfa-dominant pasture on a fertile site.

However, the value of the standing crop must be measured in the animal product from that growth. Warm-season grasses are often not efficiently utilized (trampling waste) and generally have lower nutritive value, pound-for-pound than a cool-season grass+legume. Season-long, an acre of grass+legume will usually produce more average daily gain and gain per acre than a warm-season grass during its shorter grazing season. The research data are mixed on the complimentary value of setting aside a portion of the grazing system for a warm-season grass "summer pasture" component. Results often depend on how good the components are uniform stands, short term weather influences on particular components, etc. ) Sometimes the cool-warm-cool systems provide more season-long animal production than a legume plus cool-season grass pasture alone. A recently completed grazing study in south-central Iowa showed season-long grazing of Kura clover plus grass pastures to be the most productive (animal product) system.


12. Can you stockpile alfalfa for winter grazing?

Barnhart: The legumes as a group are less useful for stockpiling and winter grazing compared with grasses in our (Iowa) climate. The nutrients leach and the leaves shatter from the plants soon after a killing freeze. While the stems - particularly the upper stem tips- retain some good nutritive value into the winter, most of the whole plant forage value drops with the loss of the leaf fraction. It is not unusual to see livestock grazing the freeze-killed alfalfa residue in corn/alfalfa strip cropped fields in the winter, so they are finding some value out there.

If you do choose to graze frosted alfalfa into the winter months, try to do it when the soil is either very dry, or frozen, to minimize hoof compaction and alfalfa crown damage.


13. What can EQIP funds be used for in rotational pasture development?

Peterson: Financial assistance can be provided to producers for a variety of conservation practices which could include but not limited to the following:

Pasture and Hayland Planting - This can be used to establish new seeding or used for interseeding to improve existing forage
Ponds - To provide water
Fence - Used to subdivide pastures
Pipeline - Used to transport water in the grazing system
Wells - To provide water
Tanks - Used for drinking facilities
Other - There are other practices that could be eligible for financial assistance

There are 100 NRCS office in Iowa (Pottawattamie county has 2). Each office can establish their priority for EQIP. Some offices focus on cropland issues others may focus on pastureland. Each office can also develop their own EQIP financial incentive program. So there are differences between office on their EQIP program on what priorities are and also on what practices they might provide financial assistance on. Anyone interested in the EQIP program in their county needs to contact their NRCS office to find out the details of the program in their county. Many NRCS offices have provided funds to producers to assist them in making improvements in their pasture systems. Producers interested should contact their local NRCS office and make their interest known.


14. What are water options for rotational pastures?

Morrical: The two options that exist are to take the cattle to water or take the water to cattle. Historically we have done the latter but for increased output we need to do the former. Moving water takes some engineering and planning. Additionally, we need to make some calculations to determine amount of water required and how to get it there.

In most rotational grazing systems, stocking rate will increase over time as pasture productivity improves. Therefore, one needs to plan for herd expansion by 50 percent or more. Cow calf pairs will consume 20 gallons per head per day and up to 30 gallon on high heat stress days. If we assume that our herd of 50 cows may expand to 100 with improved grazing management, the water delivery system must provide 3000 gallons per day. With four hours of pumping time, we would need to deliver 12.5 gallons per minute. A one-inch pipeline can only deliver that rate out to 300 feet from the pump whereas a 1.5-inch pipe can deliver 12 gallons per minute up to 2000 feet.

Pumping water is my preferred option for watering livestock in rotational system. In most cases water lines on top of the ground are the cheapest way to go. However they are higher maintenance than buried lines. Gravity flow can also be used for those paddocks below ponds. One also needs to build ponds such that they have adequate holding capacity and drainage area to keep them full.

Pushing water up hill is more challenging and takes more pressure and energy. Storage tanks located on high ground in the pasture system offers flexibility to take water multiple directions. Gas engine pumps are the easiest means of getting water pumped up hill. Combinations of multiple water delivery methods make the most sense in many systems. This could be some paddocks using gravity flow below ponds and pressure systems on wells for paddocks located above ponds.

Stream flow can be captured with water slings to pump water as can run pumps out of ponds with falling water. These systems are not very efficient and maybe restricted to watering small groups. Nose pumps are a device where cattle water themselves. Twenty-five cows per pump is the maximum and construction costs to anchor pumps can be issues.

Creativity is the best approach to water distribution is rotational grazing systems. Contacting area livestock specialists attending pasture walks and reading information in the references below can aid in developing a watering system for the grazing system.

Web references:
- From ISU: Watering systems for grazing livestock
- From Missouri Extension: All-weather concrete stock tank

Print Publications:
- Pasture Management Guide for Livestock Producers, available at ISU Extension's Online Store


15. How far should cattle walk to water?

Morrical: The quick answer is not very far, but this is also not very helpful. In New Mexico and other desert environments it is not uncommon for water locations to be spaced one to two miles apart. However, those cattle have Zebu genetics and water no more than once per day.

Behaviorally, cattle tend to water as a group. This pattern is much stronger when traveling to water located more than a quarter-mile away. An example of this in Iowa could be water available at the farmstead building site but traveling to a distant rough ground pasture via lanes. The importance of cattle whole herd watering at the same time is that tanks need to have a lot of capacity. Additionally, the water device needs perimeter to handle at least 10% of group watering at once. So if we have 100 cows in our group, the water tank needs a minimum of 20 feet of water device access, or a six foot diameter tank. Also, the tank should hold a minimum of 25% of the herd’s daily water intake or 500 gallons (100 cows X 20 gal per head per day ) which would require 10 foot diameter tank that is 2.5 feet deep.

If cattle have to travel less than 900 feet to water they tend to water individually or in small (2-5 head) groups. This reduces the cost for the water system in terms of tank capacity and water delivery rate. The size of this pasture would be roughly 9 acres if water was located in a corner. If water was located at the mid point along a fence line, then the pasture could be up to 13 acres in size and still keep the for corners within 900 feet of water.

Finally, keep in mind that how far cattle walk to water is highly dependent on levels of performance one wants to achieve. The less effort cattle exert traveling back and forth to water, the better they will perform. So as producers we must evaluate if the cost of close by water can be paid for with increased production. If you are happy with current herd production levels do not change. If you want more from your pastures and grazing herd, add closer water sources.


16. Does reed canarygrass harbor an endophyte fungus?

Barnhart: To my knowledge, reed canarygrass does not harbor any endophyte fungi, nor does it serve as a host for the fescue endophyte. Reed canarygrass can, however, produce an array of alkaloids, which are often considered as anti-quality factors for livestock.

The alkaloids that are most known and classified as anti-quality, are 3 types — gramines, tryptamines, and carbolines. Most "old," wild, reed canarygrass that is commonly found growing along streams and in wet areas in Iowa has all three! Their primary impact on livestock is that they are somehow interfering with the normal digestion of forage dry matter. Low-percentage digestion, a slowed rate of passage and reduced daily dry matter intake all lead to lower animal performance. The grass breeders have been fairly successful in selecting for an releasing reed canarygrass varieties that are substantially lower in all 3 of the undesirable alkaloids. Some of the newer varieties that may be familiar to you are: Palaton, Venture, Chiefton and Marathon. These new varieties may not necessarily be more palatable, livestock just may be able to eat more of them each day, and show better production with them, when compared with the older reed canarygrass.


17. Is it too late to frost seed legumes in my pastures? How should I go about it?

Morrical: Yes, it is probably too late to accomplish true frost seeding. By that, I mean the freeze thaw action that improves seed soil contact. Pasture improvement by increasing the legume component of pasture is always a good thing. Best success with frost seeding takes long term planning. Pastures that one hopes to frost seed in late winter need to be grazed really hard during the fall months. This management decision weakens the pasture stands and slows spring growth thus reducing the competition and shading of new seedlings. At this time of year, one should consider a no till seeder as another option to broadcast seeding. This is especially true if trying to establish legume species with expensive seed.

Barnhart: From now,mid/late March through early May, the more appropriate pasture oversowing effort should be toward the use of a no-till pasture drill and interseeding. Some additional management steps make interseeding more successful: having broadleaf weeds under control before introducing legumes; having soil pH, P and K at a level to support good legume growth; precision seed placement (1/4 to half-inch, final depth after the presswheel); having the existing grass vegetation grazed short to reduce early competition; consider using a labeled, contact, grass-suppression herbicide to further reduce grass competition while new seedlings are establishing; graze rotationally during the establishment year to keep light available to establishing seedlings; and implement grazing management in later years that helps to maintain the growth and vigor of the newly introduced forage spices.


18. I normally fertilize my pastures, but given the cost of nitrogen this spring am I wanting to be more careful? Will fertilizing a pasture still pay? When should I apply it? Are there alternatives and still get the carrying capacity?

Morrical: Higher fertilizer costs have some producers debating spring pasture fertilization. In most situations, if one is not managing the excess early spring growth, even more production is not warranted.

Currently, applying 50 pounds of nitrogen will cost around $25 per acre. That small amount of nitrogen will generate one half to one ton more early forage which is pretty cheap feed. One might consider reducing the amount of spring applied nitrogen as a means of cutting the fertilizer bill.

Another option is to split apply lower amounts of nitrogen in mid June and August to stimulate summer and fall production. If pastures have been regularly fertilized with nitrogen, one could skimp on spring applications. The other part of this question is the overall balance of forage supply versus cow herd needs. If pastures supplies are always short, I would not cut pasture fertility but might suggest one sell some cattle to reduce stocking rate. Revenue from cattle sales can be used to pay for the fertilizer if cash is in short supply.

Barnhart: Most of Iowa's pastures are cool-season grass-based — grasses that are most productive during the cool, usually moist, spring and autumn months. Nitrogen (N) provided during those periods is very efficiently used.

Iowa pasture fertility research shows the most efficient grass growth per pound of N applied with 40 to 50 pounds of N per acre, which is considered a modest rate. As the N application rate increases, the grass growth return per pound of N applied gradually lessens. So, in years of high N prices, several applications at a modest rate may be a management consideration. If you generally have excess forage during the "spring flush" of growth, then reducing your normal spring N application (or eliminating it) may be a cost-reducing option this year. Delaying your spring N application to a modest rate in late spring, May or early June, can lead to a shift of more pasture grass growth into the summer months. But, don't expect spring growth in the summer just by fertilizing with N in late spring. An additional modest N application in late summer (August) will usually produce good fall pasture production, too. While including more legumes into the grass pasture to supply nitrogen is an alternative management plan, there is a cost to this as well. It will take a year or so to get the plants established and contributing N. And, it takes about one-third or more of the pasture composition in legumes to equal the forage producing power of a modest N application.