Grazing Bites

by Victor Shelton,

Retired NRCS Agronomist/Grazing Specialist 

By November, most of us are thinking more about how much grazing remains rather than how much forage is still growing.  There still may be some growth occurring if conditions are favorable, but shorter days and cooler temperatures are gradually bringing the growing season to a close.  That doesn’t mean we should be in a hurry to graze off everything that remains.

One of the better things we can do for pastures that struggled this year is allow desirable grasses to finish the growing season without another grazing event.  Even after the first frost, cool-season grasses may continue photosynthesizing and rebuilding energy reserves whenever conditions allow.  Grazing that growth before dormancy can reduce the reserves needed for early spring growth, particularly in plants that were already stressed during the summer.

Of course, there are exceptions.  Sometimes reducing the vigor and competitiveness of existing grasses is exactly what we want to accomplish, especially when preparing a pasture for frost seeding clover later this winter.  Frost seeding red or white clover into an existing pasture can be a relatively inexpensive way to improve forage quality, increase diversity and add a source of nitrogen through biological fixation.  One of the biggest challenges, though, is getting adequate seed-to-soil contact and reducing competition from established grasses.  Grazing a pasture a little closer after it has gone dormant can help accomplish both.

That doesn’t mean we should graze every pasture down to the ground.  It means knowing what we are trying to accomplish.  A pasture with a strong stand of desirable grasses that needs more clover might benefit from closer winter grazing ahead of frost seeding.  A pasture already struggling to maintain those desirable grasses may be better left alone.  The same grazing practice can be beneficial in one situation and detrimental in another.

For most established cool-season pastures, I still like to see at least three or four inches of residual forage left behind; like always, that’s the shortest stuff.  That remaining growth serves several purposes.  It helps protect the soil from temperature extremes, rainfall impact and erosion.  If the leaves are still green and temperatures are favorable, they can continue collecting sunlight and contributing to the plant’s energy reserves.  That remaining canopy can also help suppress some unwanted plants by reducing the amount of sunlight reaching the soil surface.

In other words, what we leave behind is not necessarily wasted forage.  It is part of maintaining a productive pasture.  We sometimes get too concerned about utilizing every last bite without considering what that additional grazing might cost us later.  I’ve noted very good regeneration of existing forages when they are allowed more recovery, especially over winter.

Another consideration this time of year is what happens to certain forages following frost.  Sorghum, sudangrass, sorghum-sudangrass hybrids and Johnsongrass can all present a risk of prussic acid poisoning after frost or freezing temperatures.  Frost damages plant cells and can result in the release of prussic acid, which can be deadly to livestock.

These forages should not be grazed immediately following a frost.  A good precaution is to wait at least 10 to 14 days after a killing frost and until the plants are completely dead, brown and dried down.  A light frost can be even more troublesome if plants survive and produce new growth.  Those young shoots can be especially high in prussic acid.  If regrowth occurs, additional precautions are needed, and waiting for a subsequent killing frost may be the safer choice.  When in doubt, have the forage tested.

Prussic acid is not the only concern.  Nitrates can also accumulate in stressed sorghum-type forages, especially where drought or high nitrogen fertility has been involved.  Unlike prussic acid, nitrates do not simply disappear as the forage dries.  It is important not to confuse the two risks.

As we move farther into winter, soil conditions also become an important part of deciding where to graze.  Frozen ground can provide excellent opportunities to utilize stockpiled forage with relatively little disturbance.  The trouble often comes when the ground thaws and becomes saturated.  Hoof traffic on wet soils can quickly damage the soil surface and the crowns of desirable plants.  Sometimes moving livestock to a different paddock, feeding area or more suitable ground for a few days can prevent damage that would otherwise be evident well into spring.

I also wouldn’t be in too big of a hurry to utilize every acre of stockpiled forage before winter is over.  Tall fescue, in particular, holds its quality reasonably well while standing and can provide some useful options beyond simply extending the winter grazing season.

One option worth considering is saving some stockpiled tall fescue for spring calving.  A well-drained pasture with standing forage can provide a cleaner place for cows to calve than a heavily used winter feeding area.  It also provides some available forage during a time when spring grass may not yet be growing enough to support much grazing.  In a sense, it is standing hay that hasn’t required cutting, baling, hauling or feeding.

Of course, that doesn’t mean the cows won’t need additional feed, particularly if forage quality or quantity is limiting.  And even a good, stockpiled pasture can become muddy if livestock are concentrated on it during wet conditions.  But having that standing forage available gives us another management option when we may need it most.

Good grazing management is not always about getting the most forage consumed today.  Sometimes it is about protecting the forage we want tomorrow, preparing a pasture for improvement, or simply keeping a little standing forage available for when conditions are less favorable.

What we leave behind this fall may have just as much influence on next year’s grazing season as what we harvest now.  It is not about maximizing a single grazing event but optimizing the entire grazing season.   Keep on grazing!

Reminders & Opportunities 

BQA Training – November 12, 2026, SIPAC, Dubois. Info: Jason Tower at towerj@purdue.edu or (812)678-4427;

Small Ruminant Event – November 22, 2026 - Pinney Purdue Ag Center. Info: Call (219)733-2379 or sboyer@purdue.edu