Agronomic Management of Dairy Pastures in Temperate Climates

• A well-managed pasture can decrease operating costs while raising overall profit
• Management is the key to success in any pasture feeding program
• A proper evaluation of the present condition of the pastureland, as well as it’s potential, is necessary
• Species selection is very important to achieving long-term benefits

Although a transition into an aggressive grazing program is a learning experience, it has been shown to provide impressive financial incentives.  Studies done in the Northeast United States have found numerous dairy farms reporting a savings ranging from .50 cents to over $1.50 in production costs per cow per day. This article will examine the basic principles that have led to such successful utilization of pastureland.

Evaluation

In order for any grazing program to yield successful milk production, a proper evaluation of the present condition of the pastureland, as well as it’s potential, is necessary.  After all, the object is to provide a suitable and healthy feeding source for the herd while saving money on traditional feeds.

Soil testing

Soil testing is essential to determine the suitability of land for certain types of pastures. If legumes are to be mixed with grasses, soil pH must be at least 6.2-6.5. Potassium and phosphorus are also concerns. Medium to high levels will support maximum forage production. Select a reputable soil-testing lab and follow sound agronomic recommendations for soil fertility. 

Nitrogen levels may be addressed via the process of nitrogen fixation, but only if legumes are present and at a percentage of no less than 30. If legumes will not make up 30% of the pasture, nitrogen should be applied up to three times during the growing season (once in early spring, once in early and late summer). Applications should be approximately 50 pounds/acre each. Nitrogen is important in grass reproduction, however manure is not always recommended as a nitrogen source. This is not because manure does not supply enough nitrogen but rather because the manure makes the plants less palatable for animals and may reduce their level of feeding.  Manure also generally carries undesirable weed seeds and may allow transmission of diseases and parasites.

Existing Species

The types of grasses already present within the pastureland must also be addressed in terms of their desirability. This is also true for any weeds. Pasture composition will be an important factor in the renovation of the pasture in terms of introducing new grasses and legumes as well as control of unwanted grass or weeds. 

Special consideration should be given to certain plants that can be poisonous to dairy cows. Oleander, sudan grass, lantana, and castor bean, wild cherry, and yew, for example, have been known to cause symptoms of poisoning in cattle. These symptoms could include disorientation, labored breathing or even death. Should the herd feed on these plants the effects could be detrimental to milk production, thus making it well worth the extra effort to check for their presence.

Drainage

Adequate drainage within the pasture may not be the first thing to come to mind, but it is actually quite important to grass and legume growth that the land not be overly wet or overly dry. Adequate drainage also lessens the effects of erosion.

Water Source

An adequate water source should be provided, either natural or man-made, within a reasonably close area to the herd and protected from direct sunlight as much as possible. This will prevent the water from reaching a temperature above the optimum for dairy cows. Other special concerns include ensuring enough space per head and that troughs will be low enough in height for younger animals to drink. Improving the access to water will improve the overall health and productivity of the animals.

Renovation

When it is time to renovate a pasture, there are several choices available.

Weed Control

The control of weeds is usually the first concern before any planting can take place. It is highly recommended that a consultation with an agronomist or cooperative extension official take place to determine the best chemical weed control for the specific problem areas within the existing land. Unfortunately, there is little control for broadleaf weeds within pastureland consisting of a mixture of grasses and legumes due to the fact that the chemical broadleaf weed control will hurt the growth of legumes. For pasturelands consisting of all grasses, broadleaf weed control can be accomplished before seeding takes place. For less significant broadleaf weed problems, chemical treatment coupled with a liming and fertilization program will often give dramatic improvement to older pastures.

Seeding

Methods of seeding may vary based on land type and preference. In the colder climates, frost seeding may be used. This technique must be done during the late winter or very early spring, when the ground freezes at night and thaws during the day. The idea is that as the ground freezes at night, natural openings will form in the surface of the soil. Seed can then be spread onto the top, usually during early morning while the ground is still frozen. As the ground thaws during the day, the seed will work it’s way into the ground without further mechanical tilling. This method is dependent on spring precipitation and works best with the clover species.

Mechanical interseeding may also be used. This method involves a light to moderate disking of the top soil one to two times, followed by the broadcast of seeds into the now exposed soil. No-till seeders are also available and have proven very effective when coupled with a sound program of weed control and fertility. If no-tilling a legume, consider that clover and trefoil species are generally faster starting and more successful than alfalfa, which often struggles to become established. Orchard grass has been shown to be a good choice for a cool-season grass.  Effective burn-down of weeds prior to no-till seeding is extremely important.

Stand counts and weed percentage estimates should be done periodically to help evaluate the need for renovation. As a general rule, weed species should not comprise more than 15-20% of the estimate area. Estimates should be done systematically by randomly evaluating a number of locations in the pasture, checking an area of one square meter per stop. Grassy weed species are often less offensive to pasture productivity, followed by annual broadleaf weeds. The worst problems are generally associated with the deep-rooted perennial broadleaf species.

Species Selection and Characteristics

When considering pasture species, one should consider that mixing legumes with grass provides for an excellent source of nitrogen as well as added nutrition to the forage. Grasses will sometimes overrun the legumes in the mixture, however, so it is recommended that any mixture of the two slightly favor the legume seed in percentage. Recent research supports the theory that mixed stands usually greatly out-yield single- species pastures. Other factors such as productivity requirements, yield, forage quality and adaptation to the site must also be considered. Large systems that encompass varying soil types and drainage may benefit from custom fitting species blends to paddocks as soils dictate. Non-uniform sites will not benefit from a “one size fits all” approach. Consider areas or paddocks that are designed for times of high temperature and low recovery, or select species suited for late fall- early winter grazing if that is a requirement of the system. Species selection is very important to achieving long-term benefits. Be creative and don’t be afraid to diversify the mixtures.

The table below examines several cool-season grasses, warm season grasses, and the most common legumes to determine their characteristics, production level, palatability, grazing stages and recovery time.

Cool-Season Grasses:

Name	Characteristics	Relative field	Palatability/ Nutrient level	Grazing height	Recovery Time
Annual Rye Grass	Highly adaptive, durable	High in fall and spring, dies in summer heat	High	3” and up	Short
Orchard Grass	Tall growth, good yield potential	High with summer recovery	High	4” and up	3 wks + (summer)
Perennial Rye Grass	High quality and animal acceptance May help prevent bloat	Higher yields result from recovery period	High	3” and up	3 wks +
Reed Canary grass	Durable	Extremely high growth	Better with newer low-alkaloid varieties	3” and up	3 wks +
Smooth Brome grass	Good mixer with alfalfa	Slower to establish but good re-growth	High	3-4” and up	2-3 wks recovery
Tall Fescue	Tolerant of more continuous grazing; good for early winter grazing	Improved w/ nitrogen added during early August for winter grazing	Use low-endophyte varieties	3” and up	Short
Timothy	More tolerant of continuous grazing, high forage quality	High with only moderate fertilization	High	3-4” and up	2-3 wks recovery

Warm-Season Species:

Name	Characteristics	Relative Yield	Palatability/ Nutrient level	Grazing Height	Recovery Time
Brassicas (including kale, rape, swede)	High yield, fast-growing, can protect against summer drought	High, although some do not re-grow	High in protein, low in fiber	Matured leafs	2-3 week rotation
Chicory	Good for well drained soil, tolerant to dry conditions	Spring and summer grazing is high	Higher in nutrient value than alfalfa or other grasses	Matured leafs	2-3 week rotation
Switchgrass and Indain Grass	Tall, durable	High	Average	6-12 inches only	Moderate recovery period
Small Grains	Provide for later season grazing	High in fall, early spring	High	6”	Seasonal

Legumes:

Name	Characteristics	Relative Yield	Palatability/ Nutrient level	Grazing Height	Recovery Time
Alfalfa	Sensitive to trampling, wet periods.  Grazing types available	Highly productive	Bloat risk, Mix with a grass.  High quality	Pre-bud stage	35 days after 2 week grazing period
Birdsfoot trefoil	Grows well during summer weather unlike some grasses	Can be used to sustain summer, hot weather growth	High and does not cause bloat	Bud stage	28-35 days after 2 week grazing period
Red Clover	Mix with grasses such as timothy to reduce risk of bloat	High	High palatability and high in nutrients	Vegetative stage (spring)	28-35 days after 2 week grazing period
Common White Clover and  Ladino Types	Mix with grasses to reduce bloat risk.  Widely used in pastures	Moderate	High quality	2-3” and up	3 week intervals

Although more complicated to manage, the benefits of mixing grasses with legumes are simple. When present at high enough levels (>30% of the field), the legume species provide nitrogen (crude protein) for both animals and companion grasses. They promote a thicker pasture, which is less susceptible to weed outbreaks and erosion damage, and introduce additional nutrients into the herd’s diet as well.

Size Requirements

It is important to accurately determine how much land will be needed in order to ensure proper plant intake and stand recovery time.  Penn State University recommends that farmers first determine the number of animal units (AU) to determine the number of acres necessary.  If rotational grazing is planned (where sectors of the pastureland are kept free of animals so that plants can re-grow) one must then determine the amount of recovery time the plants need and compare this with the desired plant intake of the animals to determine how many individual sectors of pasture there should be.  Some form of temporary fencing is generally used when setting up different sectors of pasture for rotational grazing.

When calculating AU, a single 1000-pound dairy cow represents 1 AU, as does a growing heifer.  A mature, 1300-pound dairy cow is assigned is equated to 1.5 AU, and a 2000-pound bull is 2 AU.  Therefore, if a dairy farm desires to set up a pasture for five 1000-pound cows, two heifers, two mature cows, and a bull, the total AU required is as follows:

5 (1) + 2 (1) + 2(1.5) +1(2) = 12 AU total

The calculation for how many acres will be needed for 1 AU will differ both on the type of grasses and/or legumes present in the pasture (their yield and recovery time combination) and the time of year, since most do not grow as readily during the hot summer months.  Other factors that could be taken into consideration are the soil quality and soil nutrients as well as any particularly dry or wet weather.  Assuming 1 acre per AU can show a rough estimate of needed acreage, but this is only an estimate.  Proper evaluation of the factors above should always be sought from an experienced consultant.

For rotational grazing operations, the stand will be given the chance to recover from feeding while the herd is concentrated in one area for intensive grazing.  In order to figure out how many sectors to divide the pasture into, simply divide the number of days that section of the pasture will be given to recover by the total number of days that the herd will be in feeding in that same section.  Keep in mind that more plant recovery time will be needed during the summer months.  The number of days cows can remain on a paddock is determined by a combination of animal density, growth pattern of the species involved, and careful observation by the manager to monitor the height of the forage. Most pasture species should not be grazed lower than 3 inches.

Therefore, an example could be:

30 day total plant rest period/3 day grazing per sector of pasture = 10 sectors needed

Finally, by dividing the total acreage (in this case 12) by the number of sectors, we can find out how many acres in each sector (in this case 1.2).

Established Pasture Management

Once the pastureland is established, it is essential to properly manage it to ensure continued plant health and success.  One step in achieving this is with proper fertilization.  Cool season grasses generally require multiple nitrogen applications coupled with complete but careful P and K additions based on soil test results.  Regular forage testing to monitor grass potassium levels will help avoid tetany problems.  The secondary plant nutrients, calcium, magnesium, and sulfur have also been shown to help provide additional yield and quality benefits when added.  However, these benefits only occur if they are lacking in the soil.  Legumes such as alfalfa place heavier demand on potassium, calcium, magnesium, sulfur, and boron than most grass species.  Again, balanced fertility based on current soil tests is the key.  As with any crop, proper liming and pH management is essential to reach optimum conditions. 

Grazing management is also important to ensuring the productivity of pasturelands.  Continuous grazing involves animals remaining in the same pasture area without giving any lengthy time period for plants to re-grow or recover from intensive feeding.  Farms that desire to use intensive grazing as a large staple of the herd’s diet most likely will benefit from a rotational grazing plan, as discussed above, to allow for the plants to recover to an appropriate height.

Careful monitoring may be the most important factor in managing a pasture.  As intensive grazing may lead to a sector of pasture being depleted in only a matter of a couple of days, it is imperative to constantly watch feeding patterns and be ready to react.  It is the farmer who will control the diet of the herd in the long run. 

Benefits and Conclusion

A well-managed pasture can decrease operating costs while raising overall profit.  The concept is simple: spend less on traditional feed and still produce a similar amount of milk from each cow.  While there may be a small decrease in the production of many dairy cows on intensive grazing farms, net-farm income is often similar or higher. Careful management of plant health, weed control, soil fertility, species selection, a carefully planned rotation of animals within separated sectors of the pastureland and continual attention to detail will, over time, ensure that animal health and production are not compromised.  Bottom line: intensive grazing is an economical, environmentally sound, and healthy way to promote a profitable farm, especially during times of fluctuating milk prices. 

References:

Beegle, D.B., 2001. The Agronomy Guide 2002. Pastures. p. 92-101. E. Martz, Pennsylvania State University, University Park, PA.

Brett, Jim, 1999. Water: The More, the Better. www.dairyherd.com., June 1, 1999.

Cornell Field Crops and Soils Handbook, Second Ed. Pasture Management. p. 130-135. New York State College of Agricultural and Life Sciences, Ithaca, NY.

Dovers Staff, 2001. Be Aware of Poisonous Plants. www.dairyherd.com., October 25, 2001.

Hall, Marvin H., 1995. Four Steps to Rotational Grazing. www.cas.psu.edu., May 1, 1995. Pennsylvania State University, University Park, PA.

Harlow, Susan, 2001. There’s Profit in Grass. Northeast Dairy Business, November, 2001. p. 18-22.

Smith, Dale, 1975. Forage Management in the North. Kendall/Hunt Publishing, Dubuque, IA, 1978.

Unknown, 2000. Renovate Pastures to Increase Production at Lower Costs.  www.americasalfalfa.com., 2000.

Related Links:

Pasture Management
Ohio Agronomy Guide

Weed Management in Perennial Pastures and Hay Fields
B.W. Pinkerton & E. C. Murdock, Clemson University

Soil Sampling Guidelines for Assessing Soil Fertility for Row Crops,
Pastures, and Forages
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Developing a Pasture Management Program
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Bull, Plumeless, Musk, and Canada Thistle - Their Biology and
Management in Pastures
J. Doll, University of Wisconsin

Weed Control in Pastures without Chemicals
D. Cosgrove and J. Doll, University of Wisconsin

The Good, the Bad, and the Ugly of Pasture Grasses
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Grazing Management of Irrigated Grass Pastures
J.T. Nichols, University of Nebraska

Controlled Grazing of Virginia's Pastures
H.E. White and D.D. Wolf, Virginia Tech

PLANTS Database
United States Department of Agriculture