I recently met with a resident who was concerned about overgazing in a horse pasure.  After visiting the site, I observed that parts of the pasture were indeed overgrazed while other areas were undergrazed.  The undergrazed areas were wet areas while overgrazed areas were dry. 

Unfortunately, this is an all-too-common occurance with horses as they are very picky eaters. 

Horses selectively forage on highly palatable plants over and over again while leaving less palatable plants virtually untouched.  I liken it to putting a plate broccoli and icecream in front of a horse.  Just like a kid, the horse will eat the icecream first and may not touch the broccoli at all.   Overtime, the undergrazed (broccoli) areas, will mature and become even less palatable due to increased non-digestible fiber content.

Unlike other herbivores (like cows, sheep, goats, elk, deer and moose), horses have front teeth on the top and bottom. The others ony have front teeth on the bottom jaw. 

By having front teeth on the top and bottom, horses can bite plants off closer to the ground.  This can reduce plant regrowth and lead to plant death if not given time for rest/recovery.  It is for this reason that overgrazing can lead to increased incidence of soil erosion and noxious weed encroachment.  

Golden Rules of Proper Grazing Management

• Take Half, Leave Half - By removing only half the amount of leaf volume, you maximize your grazing effort and minimize your root loss at the same time.
• The last 3" don't belong to you - The last 3" inches are the plants reserves so they can continue to grow and thrive.

When putting these two concepts together, wait to graze your pastures until your grasses are 6-8” tall. Take stock off when grasses are grazed down to 3-4” tall.  Do not graze again until your forage has regrown to 6-8” tall.

 

Grazing Management in Practice

Considering the information above, how should a horse owner properly manage their pastures? 

The two sources below (or to the side) include detailed insights into proper grazing management for horses.

To summarize, horse owners may use one or more of the following strategies.

• Enact high intensity, rotational grazing between small pastures.  By forcing horses to graze in smaller areas for a limited amount of time it forces better forage utilization and minimizes selective grazing.  Electric fence can be used to split a large pasture into smaller paddocks.  This is time intensive and requires heighten vigilence, but it is highly effective in preventing overgrazing.  
• Engage in drylotting and time-limited turnouts.  By keeping horses in a corral for a part of the grazing season or a portion of everyday, you can ease grazing pressure and improve longterm plant recovery.
• If horses have an artificial water source (water trough) or horses are fed grain/mineral in a specific spot, regularly move that spot around the field to encourage horse movement and minimize overuse of a given area.  
• Stocking rates vary across the landscape based on species assemblage and environmental factors.  However, in Middle Park, a 1000# animal may require 2 acres of healthy, well-irrigated hay meadow per month.  BUT, in a dryland pasture, it may require 5-7 acres per 1000# animal per month.  Add drought into the mix and these ballpark figures go up.  

Regardless of chosen management practice, it is important that plans are flexible and adaptive.  You must continuous monitor pasture conditions and be ready to change plans on the fly to prevent longterm detrimental impacts.  Sacrifices today will lead to payoffs in the future - proper land management is a marathon, not a sprint.