Equine Pasture Management

A productive pasture that is diverse with forage species that are appropriate for South Carolina’s climate provides an economical and practical source of nutrition. Achieving healthy pastures can be challenging with the continuously changing environmental conditions and the grazing pressure that horses put on the pasture. Ideally, mature horses should be fed 1.5%-2% of their body weight in forage.¹ However, this requirement will vary greatly depending on the activity of individual horses. Good management practices to ensure pastures meet nutritional needs include soil sampling and fertilization, weed control, appropriate forage species and varieties selection, and rotational grazing.

Soil Sampling and Fertilization

Soil sampling is a critical part of maintaining a productive pasture, and soil analysis will determine available nutrients and soil pH. Maintaining proper soil fertility can be achieved by applying the recommended amount of lime and fertilizer to the pastures. Soil pH is a measure of acidity in the soil. Targeting a pH of 6-6.5 (figure 1) is best for optimal pasture growth and yield.² With the correct soil pH, nutrients in the soil will be more available to the plant. The three primary nutrients are nitrogen, phosphorus, and potassium. Nitrogen is an essential aspect of forage quality and growth; pale green and yellow plants can be a sign of nitrogen deficiency. An adequate supply of nitrogen will promote vegetative growth, and the plant will have a darker green color. Nitrogen applications should be split and applied throughout the year, depending on the type of forage. Phosphorus improves forage quality and root development and ensures higher crop quality, greater stem strength, increased root growth, and crop maturity. Potassium will help the plant survive stressful times such a drought and cold temperatures. Weak growth, reduced disease resistance, and less winter hardiness can be a sign of potassium deficiency.

Figure 1. Nutrient availability by soil pH. Image credit: University of Florida IFAS Extension.

Weed Control

Actions to reduce weed pressure must be planned and implemented. Weeds will compete with the desirable forages by consuming space, water, and nutrients away. Adequately managed pastures tend to have decreased weed encroachment. The best weed control is a healthy, desirable forage species. Although we can utilize management practices to lower weed pressure, in time, weed thresholds can be exceeded and will require the use of a targeted herbicide treatment. To reduce weed pressure, properly spray pasture using the appropriate herbicides, and always comply with the herbicide label. The South Carolina Pest Management Handbook provides information about weed control in grass forages.³ A copy of the handbook can be requested on the Clemson Cooperative Extension Agronomic Crops website.

Perennial and Annual Grasses

Perennial

Perennial grasses should be the base forage of every horse pasture. Perennials are a persistent and dependable forage that will be productive for many years with proper management. Both cool- and warm-season varieties can be grown in South Carolina (table 1). Cool-season forage grows from fall through spring, and warm-season forages grow best during the summer. When considering a primary forage, pay attention to climate trends in your area and recognize when your operation requires peak forage production. Fertility, soil type, and grazing tolerance are also essential considerations before establishing a new pasture. Cool-season perennials generally grow best north and west of the fall line in South Carolina (narrow zone of transition between the Piedmont and the Coastal Plain). In contrast, warm-season perennials grow well throughout the state. Limited amounts of cool-season perennial forages are grown in the Coastal Plains area.

Table 1. Examples of perennial forage varieties.

Annual

Seasonal, annual pastures are planted each year for summer or cool-season grazing periods of three to four months. Small grains (oats, rye, or wheat), ryegrass, and annual legumes are commonly used to provide winter grazing. These can be planted either in a prepared seedbed or in a dormant bermudagrass or bahiagrass sod. Planting in dormant bermudagrass or bahiagrass sods takes less labor than preparing a seedbed, and the bermudagrass/bahiagrass is available for summer grazing during the next season. Use clovers with caution as they have a mycotoxin that will cause excessive salivation (also known as “the slobbers”) in some equine. The condition is typically cosmetic and causes no immediate danger to the horse except in the case of excessive salivation that could cause dehydration in some horses. Summer annual pastures are usually planted with either pearl or brown top millets or crabgrass (table 2). The sorghum-sudangrass hybrids are not recommended for horses because of the potential hazard of cystitis (inflammation of the urinary tract).⁴ Nitrate accumulation can occur during specific plant growth stages and more favorable during certain environmental conditions. While nitrate toxicity is uncommon in horses, if forages high in nitrates are consumed, toxicity may occur. Forage testing can determine if nitrate is a problem in the forage.

Table 2. Examples of summer annual varieties.

Rotational Grazing

A good rule of thumb is to allow two acres of pasture per horse.⁵ Increased stocking rates require stricter management practices to maintain adequate forage health. Horses are typically “harder” on pastures when compared with other livestock, and this can be attributed to their grazing behavior, especially forage types which store reserves above ground (e.g., tall fescue, small grains, etc.). Horses are very nimble grazers, utilizing their lips and front incisors to remove forage within one inch of the soil surface. They also are very habitual in their grazing pattern, meaning they will visit the same locations in the pasture day after day. Without proper management, fields can quickly become overgrazed. Continuous overgrazing causes forage stand degradation, which can lead to environmental concerns such as erosion.⁶ Rotational grazing can help reduce overgrazing and increase plant health by giving plants time to recover both in forage, but more importantly, with root development.⁷

Rotational grazing management contributes to higher forage use efficiency. Small pastures that are rotated periodically will allow forage to rest and regrow. This prevents the horse from being selective on what and where they graze. In a rotation system, the pasture area is subdivided into several paddocks, and animals are rotated through each, based on plant growth and animal needs. Greater efficiency is reached by designing pasture systems so that the forage is provided a period of rest and regrowth. If rotational grazing is implemented correctly, the nutritional needs of the horse can be met. Considerations such as access to shade and water should be included in the planning phase before pastures are subdivided and fenced.

Conclusion

Pasture management is an integral part of raising horses. A good forage management program will not only sustain healthy horses but also provide economic longevity for healthy pastures. Contact your county Livestock and Forages Extension Agent for additional information. Contact information for Extension county offices is available on the Clemson Cooperative Extension website.

References Cited

1. Duberstein KJ. How to feed a horse: understanding the basic principles of horse nutrition. Athens (GA): University of Georgia Extension; 2015 [accessed 2020 Aug 22]. Bulletin 1355. https://extension.uga.edu/publications/detail.html?number=B1355&title=How%20to%20Feed%20a%20Horse:%20Understanding%20the%20Basic%20Principles%20of%20Horse%20Nutrition.
2. Little C, McCutcheon J. Fertility management for meadows. Columbus (OH): Ohio State University Extension; 2016 [accessed 2020 Aug 22]. ANR-5. https://ohioline.osu.edu/factsheet/anr-5.
3. Clemson Cooperative Extension. 2020 South Carolina pest management handbook. Clemson (SC): Clemson University Cooperative Extension; 2020.
4. Huntington P. Alternative hays for horses. Versailles (KY): Kentucky Equine Research, Equinews Nutrition and Health Daily; 2012 [accessed 2020 Aug 13]. https://ker.com/equinews/alternative-hays-horses/.
5. eXtension. How much land do I need for a horse? Kansas City (MO): eXtension; 2019 [accessed 2020 Aug 13]. This work is supported by New Technologies for Agriculture Extension Grant No. 2015-41595-24254 from the USDA National Institute of Food and Agriculture. https://horses.extension.org/how-much-land-do-i-need-for-a-horse/#:~:text=If%20you%20are%20attempting%20to,highly%20variable%20depending%20on%20location.
6. Al-Kaisi M, Hanna M, Barnhart SK, Tidman M. Managing pasture to reduce soil erosion. Ames (IA): Iowa State University Extension and Outreach; 2001 [accessed 2020 Aug 13]. https://crops.extension.iastate.edu/encyclopedia/managing-pasture-reduce-soil-erosion
7. University of Kentucky. Importance of rest periods between grazing. Lexington (KY): University of Kentucky College of Agriculture, Food, and Environment, Master Grazer. [accessed 2020 Aug 13]. https://grazer.ca.uky.edu/content/importance-rest-periods-between-grazing.

References Consulted

National Research Council. Nutrient requirements of horses. 5^th ed. Washington (DC): The National Academies Press; 1989. doi:10.17226/1213.

Ball DM, Hoveland CS, Lacefield GD. Southern forages, modern concept for forage crop management. 4^th ed. Peachtree Corners (GA): International Plant Nutrition Institute (IPNI; 2007.

Foulk D. Basic pasture management for the equine owner. University Park (PA): The Pennsylvania State University, Penn State Extension; 2013 [accessed 2020 Aug 13]. https://extension.psu.edu/basic-pasture-management-for-the-equine-owner.