Spring brings warmer temperatures, green grass and spring showers.  If you own livestock, it also means that you have the opportunity to begin a new grazing season and an end to another feeding season.  It is also an opportunity to improve or ruin the health of the plants in your pasture. Pasture management is more than simply opening the gate and letting the animals out to graze.

How do I manage my pastures?

April and May are critical months in the growth of a grass plant.  It is important to protect the spring growth from early defoliation by grazing livestock.  If grasses are grazed too frequently and too early in growth cycle, the root system will decrease in mass and size until they become less competitive (or die off) and undesirable plants take over. Grazed plants need time to rebuild the photosynthetic factory that was removed by grazing, and to restock the warehouse (the root system) from which the supplies for the rebuilding process was taken. If less than 50% of the leaf material is removed, then the plant can rebuild the photosynthetic tissues (the green leaves) without a drain on the root system. 

Sustainability of your pasture will be determined by your commitment to prioritize managing your pastures for forage health.  Have you inventoried your forage resources lately?  Do you have enough forage to support the numbers of livestock?  Remember the fragile nature of vegetation and soils do not easily recover from abuse. 

An inaccurate perception existing among many landowners is that small parcels of land can be grazed continuously. Proper grazing is vital to the overall ecological health of a piece of land.  Poor pasture management can lead to the absence of adequate ground cover, and subject the soil to wind and water erosion, and increased compaction.

Grazing Management

The timing of grazing has a long-term impact on your pasture.  Grazing too early in the spring can reduce the yield potential of your pasture and is the most common pasture management mistake.  Allow grass to grow before grazing a horse.  This grass growth varies depending on the grass species.  For example, it is important to allow brome grass and orchardgrass to grow to a height of 6 to 8 inches before grazing is initiated.  Each grass species has different height requirements for grazing.

The phrase “Grazing Management” is very important.  A horse that is grazing should not remove more than 50 percent of the available forage.  Simply put, if your horse eats 50 percent of the grass that was there prior to grazing, remove him and allow the pasture to rest approximately 30 days or until the grass regrows to the original height.  This approach is called “take half and leave half.”

Divide your pasture into grazing cells to allow for more rotational grazing.  After a cell is grazed, move the animals to a fresh cell while the grazed cell rests to promote new growth.  The improved management afforded by rotational grazing can greatly increase forage productivity and pasture health (figure 1).

 Figure 1: Divide pasture into grazing cells.

Resting pastures is critical! Recovery time for grasses ranges from 10 to as many as 60 days, depending upon season, weather, and soil characteristics. Generally expect to wait at least 14 days for grasses to regrow to grazing height in spring, and 30 or more days in summer. A good rule of thumb for grazing is to avoid exceeding 7 days on any one paddock. If you have enough land to do this, divide your total pasture area into a minimum of 5 paddocks, and rotate animals to a new paddock at least once a week. This system will allow each paddock to rest for 28 days.  If it is not possible to have 5 paddocks, divide your land into as many paddocks as possible to allow the areas to rest.

A rule of thumb is to graze animals when grass is 6 to 8 inches high. Be certain to rest grass when it is grazed down halfway (3 to 4 inches high).  “Graze ½, leave ½.”  Grazing 50% only removes 2-4% of growth but grazing it 60% removes over 50% of growth!  Grazing plants too short may cause horses to ingest soil resulting in sand colic.  Removing the growing points of grass requires longer rest periods for recovery, allows more weeds to invade the pastures, increases the chance for consumption of toxic plants, and increases the need for weed control. 

Experiment with portable electric fencing systems to subdivide pastures into paddocks. Paddocks are usually large pens or a small pasture that encompass one-half to several acres. Ensure that the permanent perimeter fencing is sturdy and reliable. Portable or temporary fencing allows flexibility in how much area you give your horses daily. It also facilitates mowing and haying operations due to the ease of picking it up and getting it out of the way. Over time you may find that you are placing your fences in the same places and choose to erect permanent fencing in its place.

Keep grasses in their "vegetative" state with a combination of grazing and mowing. Harvesting grass before it gets too tall will prevent it from becoming reproductive, also known as "going to seed." Mature grass is coarser, stemmy, and not as palatable or nutritious as leafy, actively growing plants. Clip weeds before they form a seed head to reduce the weed seed in your pastures. Ideally, a paddock should be mowed as soon as possible every time animals are removed and rotated on to the next paddock.  Just like grazing, you should allow grasses to grow to 6 to 8 inches and mow to 3 to 4 inches if not actively grazing to keep pasture grass healthy.

Soil test pastures to determine the need for fertilizer, and follow recommendations. If pasture is new or has not received fertilizer for many years, you may wish to test for 2-3 years in a row to establish a healthy fertility level. After that, a test every 3 years is sufficient.  Your local Extension Agent can assist you with soil testing and recommendations.

“Drag” or chain harrow pastures as needed to break up and spread manure piles.  This will help manure to be broken down more quickly, spread fertility more uniformly, and dry out parasite eggs more quickly.  During wet weather, parasites may not be controlled by this method, so manure should only be spread during dry weather periods.  Also, be sure to follow a regular deworming program. 

About the author:

Virginia Knerr has been with the Montana State University Extension Service for 19 years. She has a MS degree from MSU in Agricultural Education. In her free time, Virginia likes to ride and train horses for ranch horse competitions.  She can be reached at 406-266-9242 or acxvk@montana.edu