livestock Equine Pasture Maintenance & Renovation for South Dakota Pasture Maintenance Pasture acres needed = ANIMAL SCIENCE SEPTEMBER 2012

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1 SEPTEMBER 2012 ANIMAL SCIENCE Equine Pasture Maintenance & Renovation for South Dakota Kathy Koch South Dakota State University Eric Mousel South Dakota State University Erin Cortus SDSU Extension Environmental Quality Engineer Roger Gates SDSU Extension Rangeland Management Specialist Rebecca Bott SDSU Extension Equine Specialist Horses must consume at least one percent of their body weight in forage daily on a dry matter basis to maintain normal digestive health (Geor, 2003). Horses may obtain forage in a variety of ways, with the most commonly available sources being hay or pasture. Pasture is optimal in providing forage in an equine diet and often provides the best combination of nutrients; however, complete feeds that include some form of preserved forage are quite comparable, yet costly. Pasture provides a broad variety of nutrients to the horse, including vitamins, minerals, energy, protein and water. In some cases, fresh, clean water, salt and minerals, and forage can meet all the nutritional requirements of a horse. This will depend on the quality of the forage, and the physiological status and work load of the horse. In any case, forage in the form of pasture can provide the foundation for a nutritionally sound equine diet. A horse s intake of forage is variable, depending on the overall condition and management of the pasture, as well as that of the horse and the environment (Blake, 2010). Horses spend approximately 70% of their time on pasture grazing and 10% of their time walking (Geor, 2003). Therefore, pasture is also a source of exercise and a manner in which to minimize boredom, as an average of 19 hours of a 24-hour day is naturally spent traveling or grazing. Pasture is an excellent resource for an equine owner; however, it is important to understand basic pasture maintenance requirements in order to ensure long-term health and production of the forage base. This paper will examine concepts important to maintaining a productive pasture, as well as factors to consider when planning a pasture renovation. We will consider not only what forage species are best suited for equine use, but also those viable in South Dakota. Pasture Maintenance One must decide whether a pasture is needed as a complete forage source for the horse, as a forage supplement, or as an exercise outlet, based on equine dry matter intake requirements and pasture available (Bates & McIntosh, 2010). In order to determine for which of these options the pasture may be most suited, there are a few helpful guidelines regarding appropriate pasture stocking rates that should be noted. A good rule of thumb when measuring equine forage use is as follows: a horse will remove one pound of forage per pound of body weight each month by trampling, fouling, eating or rolling (Blake, 2010). Exercise may be the most appropriate use of a pasture that is unable to provide adequate feed. However, if the pasture is simply being used as a supplement or exercise area, it may be stocked more densely for a shorter time period, provided that weeds and heavy use areas are managed appropriately (Henning et al, 2000). Pasture longevity may be prolonged if an appropriate grazing pressure is applied and animals are stocked accordingly. Acceptable grazing pressure is related to pasture productivity. Appropriate stocking rates may be determined by performing the following calculation adapted by Roger Gates from Blake (2010): Pasture acres needed = (# Horses)*(Average Body Weight in Pounds)*(0.035)*(# Grazing Days) Average Forage Production in Pounds/Acre * 0.25 Page 1

2 Available summertime grazing days in South Dakota vary from year to year, based on environmental conditions, however, they have been reported to range from days (Smart, 2006). Additionally, average forage production is highly variable, ranging from 1200 lbs/acre to 3900 lbs/acre, based on data collected over six years ( ) (Smart, 2006). For example, assume there are four, 1,000 lb horses to move to a new acreage recently purchased. With a conservative estimate of 125 available grazing days and 2200 lbs/acre of forage production, 32 acres would be required to sustain the pasture s health and the horse s forage needs. (4 Horses)*(1000 lbs)*(0.035)*(125) = 31.8 acres 2200 lbs/acre*0.25 Horses are naturally destructive to pastures, as they are selective eaters and, if not properly managed, prone to trample and tear up sod (Blake, 2010). Horses are also known to be spot grazers; they do not naturally graze evenly, instead they select portions of an area on which to concentrate preferential grazing. These factors equate to uneven grazing patterns and increased weed growth potential. A horse also typically eats in a selected area and defecates in another, and avoids eating in areas where defecation has occurred. This creates problems in forage uniformity, as vegetation benefits from the manure fertilization and does not experience grazing pressure. Hence, the pasture is easily transformed into one with an uneven growth of vegetation. When this is factored with its natural tendency to find young, growing plants more palatable, the unmanaged horse may cause damage to even a well-maintained forage stand (Blake, 2010). Determining when to graze, and when to remove horses It is recommended that pastures be grazed when vegetation has reached six to eight inches in height, and never below a height of three inches, although guidelines may differ between grass species. Consult local SDSU Extension Field Specialists or other experts for specific recommendations. Grazing a pasture too short can result in plant mortality. Grasses are considered ready for grazing when they have reached what is known as the third leaf stage. At this stage, the plant has grown a minimum of three new leaves with collars, or bands around the stalk of the plant at the base of the new leaf (Frank, 1996). Prior to this point, the plant has not accumulated sufficient leaf area to sustain photosynthesis and fuel new growth, independent of stored nutrients from the last growing season. Length of time required for plants to reach the third leaf stage depends on a variety of factors, including plant species and environment (Haun, 1973). However, this may be estimated by measuring the number of growing degree days accumulated in the region. Native cool-grass species require approximately 1,200 growing degree days, whereas introduced species require approximately only 500 growing degree days to reach the third leaf stage (Frank et al, 1993; Gates, 2012). Introduced species such as crested wheatgrass may be ready for grazing as early as May 1st, with intermediate wheatgrass or smooth bromegrass ready by May 14th. Native pastures require additional time to mature; native coolseason may be ready by June 1st, whereas native warm season grasses require an additional month and can generally be grazed by July 1st (Manske, 1999). However, these guidelines may fluctuate according to specific weather conditions experienced both regionally as well as in each growing season. It is also best to not graze the same pasture during the same dates year to year, but alter when each pasture is grazed to avoid any accumulated damage patterns. To determine the number of growing degree days accumulated in the area, and more accurately predict grazing conditions, a growing degree days module is available from data accumulated and posted on the SDSU Climate website and may be accessed on-line at edu/awdn/archive/degreedays.asp (Gates, 2012). A good rule of thumb is to graze until half of the forage produced on pasture remains. This refers to the old adage take half, leave half which is a management practice that assists in maintaining pasture integrity. Plants are photosynthetic, and energy conversion occurs in their leaves. Consequently, they require sufficient time to establish multiple shoots and leaves in order to ensure sufficient recovery after grazing. When half of the forage on a pasture is removed, it is time to remove the horses from the pasture so it can rest and regenerate. Page 2

3 Sacrifice areas & high traffic areas When available pasture area is insufficient to provide all of the forage needs, intentional designation of a separately fenced area can be beneficial to the balance of the pasture. Termed sacrifice area, dry lot, loafing lot, or stress area (due to its inclination for heavy use, to the benefit of the main pasture area), this provides adequate room for exercise, and should also be utilized during heavy rainfall periods. Designation of a sacrifice area requires provision of feed from alternative sources such as hay, when pasture access is restricted. These areas vary in size, however, on average, an area of 1000 ft 2 is recommended for each horse (Blake, 2010). While the designated sacrifice area itself may become bare, with packed earth, proper utilization will allow the pasture time to recover from grazing. It is also important to maintain the area by proper weed control and area location, as weed growth may become prolific. High traffic areas such as areas by gates, water troughs, and feed may also become compacted or eroded over time. Strategically locating watering troughs and feeding areas in the designation sacrifice lots helps to localize high traffic areas; thus preserving more of the total pasture area. Rotational grazing Rotational grazing is another concept that, when implemented correctly, positively impacts the health of the pasture. Simply defined, rotational grazing is a system in which pastures are not continuously grazed; instead are allowed periods of rest between grazing intervals. This ensures that new plant growth has adequate time to recover and establish new leaf material to withstand trampling and grazing. Rotational grazing systems may range from simple to elaborate; however, the idea remains the same. Partition the pasture into several small sections; generally, three to four smaller plots is recommended. Thus, the grazing patterns of the animals may be better regulated, as they are restricted to a smaller area, and are consequently rotated through the plots as needed. This system, when used in conjunction with a sacrifice area, will allow the pasture proper recovery time and will decrease stress on the pasture (Blake, 2010). Rotational grazing provides environmental benefits as well, when applied to riparian areas. These areas are adjacent to water sources and serve to slow erosion and improve water quality by decreasing non-point source pollution (Anderson and Masters, 2009). Prolific riparian areas function to trap run-off, degrade chemicals, filter sediment and recycle nutrients (Bellows, 2003). Rotational grazing allows for better pasture management and avoidance of overgrazing in riparian areas, which can result in sod deterioration, as plants are unable to develop adequate root systems (Pillsbury and Undersander, 1999). To ensure the health of riparian areas, it is recommended to restrict animal access once forages have been grazed to a height of four inches. Fertilization Soil fertility should also be considered for proper pasture maintenance. As horses obtain nutrients by eating pasture forage, it is important that the pasture be adequately prepared to do so. In order to correctly meet the needs of the pasture, a soil sample must be analyzed. Soil testing may be accomplished by taking an aliquot, or small sample, of soil from the pasture in 20 different locations, each at a depth of six inches below ground. Mix the samples together, to create a composite sample that best represents the nature of the pasture s nutrient profile. This composite must then be sent to a testing center, which will analyze the nutrient content of the soil. The soil sample analysis will also illustrate both the ph levels and nutrient abundances of the soil, so the forage best suited to the soil s nutrient and ph profile may be selected. Grass pastures thrive best in soil with a ph range of , while legumes thrive best in ph ranges of Therefore, legumes prefer soils that are slightly more basic in nature than that of grasses (Taylor, 1998). The nutrient availabilities illustrated by the soil sample analysis will help determine what the soil is lacking and what is needed to compensate for any deficiencies, or perhaps excesses of nutrients. It is vitally important that one fertilize the pasture according to the results of the soil test, and what is needed. Over-application of nutrients may be as detrimental as a nutrient deficiency (Bates and McIntosh, 2010). As grasses are not able to fixate nitrogen, as legumes do, many grass species benefit from added nitrogen. Legumes respond Page 3

4 well to applications of lime, potash or phosphorus. A pasture comprised of a grass-legume mix, with 40% of the pasture comprised of legume, often does not require additional nitrogen (Blake, 2010). The local fertilizer dealer may help match an appropriate fertilizer mixture for the specific needs, based on the results of the soil test. Fertilizer costs should be carefully considered. Increased forage yields from added fertilizer are, of course, desired, however, only approximately one-fourth of the increased production resulting from fertilizer application is actually consumed by the animal. Therefore, fertilizer costs should be compared to harvested feed costs to determine economic practicality. Any horse manure left on pasture, or applied to the pasture must be taken into consideration when formulating fertilizer, as it contributes nutrients to the soil (see Cortus and Bott, 2012 for more information). Additionally, it will also spread weed seeds and could act as a vessel to spread parasite populations as well. As mentioned earlier, horses tend to defecate in specific areas, and this leads to an uneven appearance of land with mowed areas where horses have eaten and taller areas where grasses grow up around manure. The fecal material will dry out within a few days, but the nutrients and organic matter take longer to decompose. Nutrients in manure can be absorbed into the soil where the manure is deposited, but can also be carried away by runoff following rain. This uneven distribution of manure can be corrected in part by harrowing/dragging pastures to evenly disperse the manure. Fertilizer, whether manure or commercial, may benefit grass but can impair water sources. If fertilizing areas near a water source, such as a creek or reservoir, it is prudent to provide a buffer strip of grass and other vegetation to act as a filter. This buffer area slows down water movement, allowing time for nutrients and solids to settle, and prevent contaminants in water and soil runoff from reaching other water sources. Vegetation can, in turn, use the nutrients. Necessary dimensions of a buffer strip depend on the slope of the land, type of vegetation and soil characteristics. If a stream, pond or other water body is the primary water source for the horses, consider an alternative drinking source further inland away from the water bank to reduce nutrient loading on the water body. If an alternate drinking source is not available, limit the time horses spend in or near water by providing shade elsewhere. It may also be beneficial to fence off a portion of the water source and alternate between partitions. Additionally, large aggregate or gravel can be located around the water access points to discourage horses from congregating near the water for extended periods of time, while still allowing drinking access. Weed control Weed control is most often regulated in three fashions: manual removal (physical), herbicide application (chemical) and mowing (mechanical). Manual removal is the most labor-intensive method, however, it is highly effective, as there is minimal risk of damage to desired species. Herbicide application may be adjusted for use in a variety of situations; however, it is accompanied by risk of damaging desirable forage, as it may drift or wash into unintended application areas. Herbicide application must be well-researched prior to implementation, as there are many types of herbicides available and each is specifically designed to target certain weed species. Different herbicides also use various modes of action in order to kill weeds. Some may be fast-acting and others may be slow to kill, so it is important to follow directions and use appropriate measures to ensure the safety of the pastured animals. Proper herbicide selection will match the herbicide to the pasture s needs, based on the weed types present and application abilities of the operator. Depending on the efficacy and potency of the herbicide, some require operator certification in order to be used. Check with the local herbicide dealer and Extension Center for recommendations. Mowing is another weed control method widely used by horse owners. While this method greatly increases the aesthetic value of the pasture, it does not adequately eradicate weeds; it simply reduces them. Therefore, mowing is best used as a supplemental application to one of the aforementioned weed control methods. Mowing annual weeds prior to seed production will help prevent future production. Additional information regarding pasture and range weed control may be found in SDSU Extension document FS525P, Page 4

5 which outlines specific guidelines for control methods for many weed species, including selection, formulation and grazing restrictions for several herbicide varieties. This document may be accessed electronically at articles/fs525p.pdf. Noxious Weeds within South Dakota South Dakota has 1.4 million acres of grass hayland and 24 million acres of pasture within its borders (Deneke et al, 2010). Consequently, proper maintenance and weed control measures are highly encouraged, especially with regards to noxious weeds. Legally, a noxious weed is any plant designated by a Federal, State or county government as injurious to public health, agriculture, recreation, wildlife or property (Sheley et al, 1999). They are problematic for crop and livestock producers; equine owners are no exception. Weeds identified as noxious within the state of South Dakota include, but are not limited to: Canada thistle, leafy spurge, salt cedar, purple loosestrife, chicory, musk thistle, St. Johnswort and poison hemlock. A complete list of noxious weeds, as well as specific control guidelines and herbicide recommendations may be found in SDSU Extension document FS525N, which may be accessed electronically at sdstate.edu/agbio_publications/articles/fs525n.pdf. Pasture Renovation Options In order to construct an appropriate renovation protocol for a pasture, one must first ascertain what is expected of the pasture. Once the goals and stocking rates have been determined, decisions can be made regarding renovation. Determining if partial or full renovations are necessary Renovations may occur as needed, whether partial or full (Taylor, 1998). Generally, a pasture is considered to be in need of a full renovation if it is comprised of <40% desirable forage species (Tregoning, 2005). Similarly, a partial renovation may be all that is required of a pasture that is between 40-75% desirable forage. If the pasture were stocked with a healthy percentage (75%) of adequate forage, a renovation may not be successful, as new plants would face severe competition from existing vegetation and would not easily thrive. In this case, it would not prove to be economically feasible to renovate (Tregoning, 2005). Forage species selection Now that we have discussed pasture use and renovation, let us evaluate the forage species that may be most beneficial to the pasture s integrity. Pastures most able to meet the nutritional needs of equines consist of a grass-legume mix (Bates and McIntosh, 2010). A mixture of cool and warm-season grasses is very desirable. Cool-season grasses are most productive during cool weather, such as May- June or September-October when rainfall is sufficient for regrowth. Examples of some perennial (live more than one growing season) cool-season grasses include smooth bromegrass, Kentucky bluegrass, orchardgrass or timothy. It is important to note that tall-fescue varieties used in equine pastures that house breeding or young, growing horses must be labeled as endophyte-free. Some varieties naturally contain an endophyte, Acremonium, which may lead to reduced reproductive efficiency, late-term abortions or delayed growth. Warm-season grasses are best suited for warmer weather conditions, typically found during the months of June-August. Perennial examples of warmseason grasses include big bluestem and sideoats grama. Big bluestem is one of the native grass varieties of South Dakota. Native varieties of the Northern Great Plains region, which includes western South Dakota, provide high quality forage and are well-suited to the area (Holecheck and Herbel, 1982). Native grass varieties for this area include not only big bluestem, but also blue grama, western wheatgrass and buffalograss. Native grass varieties that are prolific in the Tall Grass Prairie region of the United States, including central and eastern South Dakota, are Indiangrass, big bluestem, sideoats grama and little bluestem (Holecheck and Herbel, 1982). Alfalfa is a common legume fed to horses. It is generally recommended to not exceed a 50:50 ratio of grass to legume when seeding a pasture. This will help to ensure that the pasture has a balanced nutrient profile and that the forages may coexist without overtaking each other. Due to the often harsh weather conditions of South Dakota, it is recommended to seed a cool-season Page 5

6 grass and legume combination. Kentucky bluegrass is a very popular grass for equine owners, as it tolerates heavy grazing well. However, it is neither very droughttolerant nor productive. Timothy and orchardgrass are well suited to higher precipitation regions of South Dakota, while smooth bromegrass and wheatgrass are appropriate in drier areas. If legumes are not incorporated into the pasture mix, a warm season grass, such as sideoats grama, may provide appropriate forage variety. Seeding considerations Effective pasture renovation incorporates weed control on new seedings and may occur in three primary forms: frost-crack seeding, soil disturbance and no-till. Frost-crack seeding requires the least amount of labor and is also the least expensive application. However, frost-crack seeding has the greatest risk associated with it, as its success is greatly dependent on weather conditions. To perform frost-crack seeding, the forage seed is simply broadcast over a selected area. This method relies on the natural freezing, thawing and cracking of soil that occurs during late winter or early spring. Seed falls into the cracks in the soil for germination. However, much of the seed may be wasted if it is left topside, or is blown or washed away. The second method, soil disturbance, is most commonly utilized during full renovations. This is the most labor-intensive method, but is also the most successful in eradicating undesirable forage species. Soil disturbance consists of plowing or disking the selected area to break up the soil and destroy any existing vegetation, followed by seed integration into the soil. In order to ensure proper seed to soil contact, the soil must be disked to the proper consistency. The soil should be free of any large clods, but not as fine as a powder, as seeds may be lost in the wind or not have an appropriate soil depth. This application is suitable for both small and large pasture plots. Light application of an appropriate herbicide may assist in killing weeds that emerge following plowing and disking, provided that the desired grasses and legumes have not begun to emerge. No-till drilling is the final method commonly used for renovations. This method has minimal soil disturbance, so is preferred for use in high-erosion areas. It consists of drilling seed into an established pasture plot. Therefore, it is an excellent manner in which to introduce new forage species, such as legume integration into a pasture. However, the amount of existing vegetation must be considered, as the new plants will compete for moisture and nutrients with these established plants. No-till seeding will require suppression of existing vegetation, either band or broadcast herbicide application. Spring pasture seeding is successful when adequate moisture is available, however oftentimes fall seeding is beneficial, as fall and winter accumulated moisture is available for new seedlings. It is also best for freshly seeded pasture to rest for at least one season before grazing. Summary Horses possess sizeable forage dietary requirements. Pasture is an advantageous resource for ensuring the horse is meeting forage requirements. However, pasture care is often overlooked resulting in poor stands and mediocre productive capabilities. Once it has been determined what the pasture should accomplish for the equine nutritional program, one may have a better understanding of whether or not pasture renovation is indicated for the situation and how to undertake the task. Understanding the basics of pasture maintenance as discussed in this paper will assist horse owners in achieving the dual goals of increased pasture health and longevity as well as providing a nutrient-rich forage source for their animals. Acknowledgements The authors thank Mindy Hubert and Janna Kincheloe for content review, and Cheryl Beste for editing. References Anderson, S. and Masters, R. (2009). Water Quality Series: Riparian Forest Buffers. Oklahoma Cooperative Extension Service. Document NREM Accessed April 16th, 2012 at edu/docushare/dsweb/get/document-2227/nrem- 5034web%20color.pdf. Bates, G., MacIntosh, B. (2010). Pastures for Horses. University of Tennessee Institute of Agriculture. Accessed September 14, 2010 at tennessee.edu/publications/documents/pb1651.pdf. Page 6

7 Bellows, B. (2003). Managed Grazing in Riparian Areas. ATTRA. Accessed on April 16th, 2012 at Grazing%20Management/Riparian%20grazing.pdf. Blake, P. (2010). Horse Pasture Management-Basic Land Stewardship Concepts. USDA NRCS: Napa, California. Accessed September 14, 2010 at naparcd.org/documents/nrcs_horsemanagementbasiclandstewardship.pdf. Cortus E., Bott R.C. (2012). Manure Management for Horse Owners. SDSU Extension, igrow Solutions. Deneke, D. L., Moechnig, M., Wrage, L.J. (2010). Weed control in pasture and range: South Dakota State University Cooperative Extension Service. Accessed August 15, 2011 at Frank, A.B., Sedivec, K.K., Hofmann, L. (1993). Determining Grazing Readiness for Native and Tame Pastures. North Dakota State University # R Accessed August 17, 2012 at pubs/plantsci/hay/r1061w.htm. Frank, A. B Evaluating grass development for grazing management. Rangelands 18.Gates, R. (2012). Determine when to begin spring grazing. High Plains/Midwest AG Journal. Issue date Accessed April 17th, 2012 at Haun, J. R Visual quantification of wheat development. Agron. J. 65: Henning, J., G.D. Laufield, R.J. Colman, L.M. Lawerence. (2000). Establishing and Managing Horse Pastures. University of Kentucky College of Agriculture Cooperative Extension Service. Accessed September 14, 2010 at pubs/id147.pdf. University Cooperative Extension Service. Accessed April 16th, 2012 at pasture-turnout-recommendations/. Moechnig, M., Wrage, L.J., Deneke, D.L. (2011). Noxious weed control: South Dakota State University Cooperative Extension Service. Accessed August 15, 2011 at Nadeau, J Pasture: Planning, Seeding and Sacrifice Areas. University of Connecticut Department of Animal Science. Accessed September 14, 2010 at Sheley, R.,J. Petroff, M. Borman, (1999). Introduction to Biology and Management of Noxious Rangeland Weeds, Corvallis, OR. Oregon State University Press. Smart, A., E. Mousel Predicting forage production, stocking rate and beef production in eastern SD: a case study. South Dakota State University BEEF Report 10. Taylor, Dr. R. (1998). Pasture Renovations. University of Delaware College of Agriculture and Natural Resources Cooperative Extension. Accessed September 14, 2010 at 06.pdf. Tregoning, D. (2005). Pasture Renovation and Seeding. Montgomery County Cooperative Extension. Accessed September 14, 2010 at pdf. Undersander, D. and B. Pillsbury. Grazing Streamside Pastures. University of Wisconsin-Extension. Document A3699. Accessed on April 16th, 2012 at ftp://ftpfc.sc.egov.usda.gov/mi/ecs/grazing/grazingstreamsidepastures.pdf. Holecheck, J.L. and C.H. Herbel. (1982). Seasonal Suitability Grazing in the Western United States. Rangelands. Vol. 4. No. 6. p South Dakota State University, South Dakota counties, and USDA cooperating. South Dakota State University adheres to AA/EEO guidelines in offering educational programs and services. Publication: Page 7