Animal Health Notebook
Cows grazing dry native forage Alan Newport
Long-term grazing planning requires a lot of knowledge. Prepare yourself.

Cheatgrass, fire, grass tetany, hay and native grass

Here’s about a hundred things to think about when planning your grazing.

I have spent the last 40-plus years practicing veterinary medicine with cattle producers and feeding grazing cattle. Much of what I have learned came from older producers many years ago. Some of the info took me decades to actually digest. But eventually a bunch of this stuff has made sense and has application in our present management system and my recommendations.

Our local soil is described as “ultisol” which means that these red clay soils are very much overdeveloped and very low in calcium, most other minerals and trace minerals organic matter (carbon), and quite shallow. It is near 100% clay. Most of the pasture ground quickly moves to broomsedge (sage grass) if grazed without significant inputs of calcium and phosphate. We actually have decent levels of phosphorus but it is closely bound to aluminum and/or iron.

Before the introduction of imported cool-season grasses (KY31 fescue), petroleum-based salt fertilizers, lime and some government support it was common for natives to burn pastures on an annual basis. There is/was no historical evidence that regular burning had any real positive affect, although short-term there may have been some release of new spring growth with a cool fire, with some increase in palatability. Concerning cheat grass in the west, I have seen near pure stands that quickly become mature and are full of seeds that cause problems with eyes and nasal orifices. Palatability quickly heads south and I agree with Alan Newport’s article on grazing firebreaks in the April 2019 edition of Beef Producer.

In June of 2018, I saw thousands of acres of cheatgrass following the Northern Plains drought and chronic overgrazing of 2016-17. It was interesting that Ray Banister had no “blow-up” of cheatgrass on his East Montana pastures that are completely recovered following severe grazing. Banister has been severely grazing for most of 40 years. He follows the grazing with complete plant recovery. Hence his description of “boom and bust” management.

In April 2019, his cattle were grazing in forage that was belt-buckle tall. His biggest problem was that he could not see and count the baby calves: You should not drive a truck in his calving pasture! The point here is to remember that high-density, severe grazing following complete plant recovery prevents fire hazards and long-term monocultures. The answer to pollution is dilution. Diversity yields stability.

Fire can be a really good tool but should seldom be used on a regular basis. Fire limits plant diversity and limits and prevents soil development.

Furthermore, the dreaded grass tetany is a manmade problem and the following facts need to be remembered:

  • Soil potassium levels above 3% are dangerous.
  • Fertilized and/or lagoon spread ground is dangerous.
  • Low plant phosphorus in the presence of nitrogen and potash is dangerous.
  • Lush pastures that have been chemically or compost fertilized are dangerous especially if they are lush and lack dry matter.
  • Cows that are scouring and have young calves are risky.
  • Feeding high magnesium mineral does not eliminate Grass Tetany.
  • Potash (Potassium) in excess (above 3%) is probably the most important point. See the European work that Andre Voison published in the 1950s in his book Grass Productivity.
  • Readily available loose salt is a plus.
  • Calving after the forage has strength and the manure is stacking is hard to beat.

Perennial, native tallgrasses win out over imported grasses, especially cool-season, imported grasses for lots of reasons in much of North America for these reasons and more:

  • Biomass production
  • Depth of root system
  • Nutrient density
  • Less water dependency
  • Soil development
  • Cattle gains per acre
  • Lower cost of gain and cattle maintenance
  • More cell wall starch and less simple sugars as compared to C3 plants

Tall, warm-season grasses often show 200-300% increases in profitability per acre when compared to alfalfa, fescue and bermudagrass, but there are considerations that need to be reviewed and understood.

First, realize that the natural model includes the tall, warm-season C4s to the tune of 30-60% of the stand, along with lots of other forbs, herbs, legumes, short C4s, and several C3 cool-season grasses.

Tall, warm-season grasses cannot withstand long-term set stocking or the constant presence of cattle or the regular rapid return of the herd.

Fire removes much of the tall warm season advantage since much of the carbon becomes CO2 in the smoke. The forage produces less production per acre following fire and reduces plant biodiversity. Also, plants that cannot handle fire will disappear, reducing biodiversity.

Some soil types are not a good natural location for many of the tall, warm-season grasses. The clay of the Cumberland Highland Rim in my areas is a good example. Purple top does good where I ranch. Big bluestem, Indiangrass, Eastern gamagrass and little Bluestem do not thrive there. The imported Johnsongrass does well here with limited tillage.

Perennial warm-season tallgrasses are where most beef producers need to address interest and at least a little effort. The pluses are real, but pure stands are not the answer and are loaded with problems. Instead, manage for:

  1. Plant diversity that yields stability
  2. Cattle moving in high densities (70,000 pounds per acre)
  3. Complete plant recovery
  4. Chaotic timing of grazing
  5. A little year-around green
  6. Fire no more often than 5-20 years

I totally agree that fire should be an ever-present part of ranch planning and execution. Wild fires, floods and droughts are expected, if not predictable. They will happen. It is not a matter of if they will come. It is a matter of when. Planning, monitoring, education and execution allows us to neutralize their effects and damage. The cattle can pay for these neutralized effects.

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