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Six common myths in grazing management

Brian W. Sindelar Published on 22 June 2012
White Park cattle in field

Good grazing management is a common goal on rangelands but, unfortunately, not all of us know exactly what it is.

This is partially because of several common myths in grazing management. These myths persist for a number of reasons but probably mostly because it is easier for us to accept what is already accepted.

Will Rogers summed this up by saying, “It isn’t what we don’t know that gives us trouble – it’s what we know that ain’t right.” I’d like to discuss several common grazing myths.

1. Grazing management systems are something new. With the domestication of cattle, sheep and goats about 10,000 years ago, man assumed the role of herdsman and began to affect his environment as significantly with grazing as he did with fire.

All of the consequences of bad grazing management inevitably appeared, including erosion, disappearance of plants and desertification. The better herdsmen were certainly aware of the cause-and-effect relationships between animals and environment.

Over the centuries, a knowledge of grazing management evolved and was recorded, among other places, in the Bible. We usually associate rest rotation grazing with Gus Hormay, who experimented extensively with it beginning in the late 1950s.

Not as many of us are aware of the grazing research of Jared Smith (USDA Division of Agrostology) in Kansas and Texas. In 1895, he developed and advocated what we know now as rest rotation grazing. There isn’t much new under the sun.

2. Overgrazing is a result of overstocking. Under most grazing systems, control of the animal’s grazing behavior is quite limited.

During the time animals are in the pasture, they have unlimited access to all plants and all portions of the pasture for the entire grazing period.

There is no way for the manager to ensure that repeated grazing of an individual grass plant will not occur. This is overgrazing and nothing else is.

A 500-acre pasture may have two cows in it for five months and overgrazing of some plants will occur. Why?

Because a plant that has been previously grazed and has some regrowth is much more likely to be grazed than a plant that has not been grazed.

An individual grass plant will never know whether it has been repeatedly grazed (i.e. overgrazed) by one individual cow or once each by a dozen. Overstocking simply allows the overgrazing of many more plants to occur.

3. Grasses have “root reserves” used for regrowth. The myth of grass plant “root reserves” has been disproved by extensive research using radioactive tracers.

Almost all storage of reserves occurs in the stems and stem bases (and in the rhizomes of sodgrasses). This doesn’t mean that roots aren’t important – for their role in accessing moisture and nutrients is absolutely vital.

Repeated grazing can greatly reduce root volume but, as researcher Larry White summarized, “Nonstructural carbohydrates in the roots of grasses are not used directly in herbage regrowth following herbage removal.”

4. “Take half, leave half” is a good rule of thumb. If the stocking rate and grazing period are to be adjusted so that the animals “take half and leave half,” some sticky questions must be raised.

Half of what should be left? Should half of each forage plant be left or should half of the forage crop be left? Should half of the forage plants be grazed and half be ungrazed?

Convincing a cow to eat 50 percent of each plant has not been successful. More often a cow will utilize 100 percent of a plant she prefers, while using zero percent of a plant she does not prefer, often of the same species. Additionally, utilization will be greater in terrain and habitat preferred by the animal.

While the “take half, leave half” idea hasn’t a hoof to stand on, it isn’t all bad. Focusing some attention on the plants and their needs is good.

The important point to recognize is how little control of an animal’s feeding behavior the grazing manager has when using traditional management schemes.

5. Long-term range rest is good for forage plants and range. We know that most of our grasslands evolved under grazing pressure from bison and other ungulates in large numbers.

Major forage species developed considerable resistance to grazing and, in fact, are stimulated by proper levels of defoliation. Many forage species and range ecosystems require grazing for optimum vigor and production.

But how much rest does a grazed plant require for recovery? The recovery period necessary (when growing conditions are favorable) is probably not more than 40 to 60 days for many species.

Over-resting of range and forage plants results in stagnation and often in weed infestation. In healthy range ecosystems, a large proportion of the standing crop is “pre-digested” by a variety of herbivores before soil decomposers begin their work.

6. Allowing grasses to set seed before grazing will result in establishment of grass seedlings and range improvement. One of the more interesting myths concerning grazing management is the supposed need for seed production and trampling to establish more grass plants.

Many range scientists have advocated resting range to allow seed production, followed by grazing to trample the seed into the ground, followed by resting to allow seedling establishment.

My own research and that of others indicates that this typically does not work. The major reproductive mode in perennial grasses is the asexual or vegetative process of tillering.

Many bunchgrasses have lifespans in excess of 30 years, while rhizomatous grasses may live hundreds of years – thus there is limited “need for seed.” Drought, depredation and competition from established plants are major limitations to grass reproduction from seed.

Wheat plant

New directions in grazing management are needed

While these and other myths are relatively easily disproved, replacing them with truth and reality is more difficult.

Grazing management is basically a process governed by a number of physical and ecological principles. Unfortunately, we haven’t fully understood all of the principles involved and this has caused us some problems.

The fact that these myths have persisted for over 50 years and are being perpetuated suggests that optimal grazing management will be slow in coming.

But as acclaimed physicist Max Planck once noted, “A new scientific truth does not triumph by convincing its opponents and making them see the light but, rather, because its opponents eventually die and a new generation grows up that is familiar with it.”  end_mark

Brian Sindelar lives in Belgrade, Montana. Click here to learn more.

PHOTOS

TOP: Overstocking is not directly related to overgrazing (repeated defoliation during fast growth). An overgrazed plant doesn’t know or care whether there are 500 cows in the pasture or five. Overstocking simply results in more plants being overgrazed if the grazing period is excessive.

BOTTOM: Resting range for seed production, then grazing and trampling for establishment, seldom directly results in range improvement. The primary reproductive mode of perennial grasses is tillering or rhizome production. Photos courtsey of Brian Sindelar.

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