Grazing Management Principles

March 13, 2023

In pasture management, one of the phrases that best describes conventional grazing is “Understocked and overgrazed”. When we say that a pasture is understocked and overgrazed, it may sound like an oxymoron, but it is not if we can understand the implications.

What does understocked mean? When a pasture is understocked, there is not enough livestock there to eat the forages down to a desired level in the desired amount of time. This means two things: (1) some plants will be overgrazed while other less desirable plants are under-grazed, and (2) there will be less trampling effect and also uneven manure incorporation.

Or perhaps we could say it in a more positive way. When we increase the stocking rates in a given pasture sufficiently, we will get an effect similar to what the buffalos created in by-gone times. What happens is that when we have animals closely grouped, they create a scenario where there is less selecting and rejecting; where most of the species are uniformly clipped off, or if refused, it is trampled into the ground because of the moving herd. And because there is a moving herd, the manure will be spread consistently as well.

And also very importantly, when we have a strong-enough stocking rate, the pasture is clipped down in a matter of half a day instead of 3 days. This is very important and will lead us into second part of the conversation.

What does overgrazed mean? First of all, if your goal is to enhance forage production and regenerate soils, you minimize overgrazing of any plant. Overgrazing occurs when a plant that was grazed is grazed again between the time that the plant is sending forth new shoots and when the roots have sufficiently recovered from the grazing. This can happen in the grazing period if the plant is exposed to the animals for too many days or if they are around to graze again during the time that the plant is trying to regrow. Or it can happen during the recovery period when animals return and graze the plants too soon while they are still reforming the leaves and they have not yet reestablished their roots. I would like to expand a little on both of these.

The grazing period: After the cows have been in a paddock for a day, the roots and the crown will send energy from themselves into the shoots to create new shoot growth. This sounds easy enough but the challenge is that when the roots do so, there roots essentially start dying down to some degree and eventually they die off. This is not a problem when grazing is not misused because the new shoots that are popping out will photosynthesize and send new energy, in the form of sugars and carbohydrates, into the roots and then they will start to regrow. The problem is when the livestock is in one area too long and after 1-2 days, they also start eating the regrowth that is coming up. Now you have a situation where the roots have almost depleted their energy investing in future sugars that they will get from the shoots that they are investing energy into. Such a plant will have a very long and slow recovery.

The recovery period: By extension of what we just talked about, the recovery period needs to be long enough that the roots can sufficiently recover from the investment that they made into new shoot growth. This recovery period is not set by the time factor (as in grazing every 34 days), but rather, it is determined by how fast the forage has regrown.

As the season progresses, the major problem that I see happening is that too many people will continue with their spring time rotation, even though the grass is not as tall as it was in the spring. This creates a problem because the roots no longer have the capacity to fully redevelop before they are clipped off again.

I do want to mention that some of these principles vary slightly around the world due to moisture. If you want to learn 2 things from this topic, please learn these: (1) in some way, you should increase the stocking rate of your paddock (either by increasing number of animals in your herd or by cutting down your paddock size) so that you can be off that paddock within 12 hours after the grazing in that paddock has started and so that you get a trampling effect, and (2) manage your paddocks based on the growth factor rather than going by a strict time period or rotation.

If you want to learn more about this, I suggest that you buy Alan Savory’s book Holistic Management. Alan is a great authority on managed grazing because of his experience in reversing desertification in many countries.