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Which pasture is better for grazing? A or B?

More pasture divisions mean more opportunity for forage

The two diagrams accompanying this article represent two nearly identical ranches. They are the same size and if you count, they have the same number of cows. They even get the same rainfall and are in the same area. However, I would be willing to bet that one of these ranches has a lot more grass than the other. Any guesses which one? Ranch B is the winner of the forage contest, but let’s dig into what these two illustrations can show us in our efforts to grow more forage on the same acres.

The first thing you may notice is that Ranch B is fenced into quarters. While four paddocks are not likely an ideal number either, it serves to demonstrate the grazing concepts.

The components

  • Pasture — I think most of us could identify what a pasture is. It is a slight twist of nomenclature but both Ranch A and Ranch B could be said to be a single pasture. Some might refer to Ranch B as having four pastures and that is fine as well. Sometimes you will hear a pasture referred to as a ‘grazing cell.’ A ‘pasture’ generally refers to a continuous block of forage.
  • Paddock — A paddock is a division in a pasture. In this case Ranch A has one pasture, consisting of one paddock. Ranch B has one pasture consisting of four paddocks.
  • Carrying capacity — This is a measure of how much forage is available for animals . In this case, each ranch may have the same carrying capacity.
  • Stocking rate — This refers to the number of animals carried over time. In this case, both ranches have the same number of cows and we will assume they keep them year-round. The ranches each have the same stocking rate. The stocking rate and the carrying capacity ideally work out to the same value so that the ranch does not waste resources or overuse them.
  • Stock density — This can be described as the number of animals on a given area at a specific point in time. Each ranch as a whole has the same number of animals but the cows on Ranch A are spread out across the whole ranch. On Ranch B the cattle are grouped into one corner. Ranch B has a much higher stock density (four times more than Ranch A) since the animals only have access to one corner. A good way to visualize stock density is to use the extreme example of when your cows are in a corral (high stock density) versus in a pasture (low stock density).
  • Rest — This does not refer to animals. Rest is the time while plants are not grazed. On Ranch A, every plant has a chance of being grazed every day. There is no rest period. On Ranch B, three-quarters of the plants are rested at any point in time, since the cows can only access one quarter of the ranch. This is the first big clue as to why Ranch B might have more grass than Ranch A. On Ranch B each plant has three days to regrow for every day it is grazed. Although it may seem obvious, it is worth stating that letting plants grow produces more forage.
  • Overgrazing — Grazing a plant before it has fully recovered from the previous grazing event.

Rest is key

These basic ideas are the start of any attempt to grow more forage, but the key to this is resting parts of the ranch. Grazing management is nothing more than creating time for plants to grow (biological time). If you imagine yourself as a plant, cows turned loose on your pasture for extended period means you don’t recover from being grazed before being attacked again. This gives the advantage to plants with defence mechanisms such as low growth profiles (short little leaves), poor taste or palatability, thorns or woody stems. Cattle avoid them and over time they can take over a pasture.

There are symptom treatments such as chemicals for these types of problems, but without rectifying the root cause of limited recovery time, the problem can not be solved.

Stock density is also one of the tools to increasing forage production, and often one that people really worry about. What about when they use all the forage in their paddock? Won’t it be hard on that paddock? These are common questions and valid concerns. Stock density will absolutely increase if you put your animals into a smaller paddock or subdivide the ranch. However, every other paddock will also be growing without animals taking down that forage. The paddock with higher stock density will likely have more even forage utilization and once it is grazed, it needs to have the animals removed and be given a chance to regrow.

One of the greatest misconceptions I have run into is that you should start opening gates during drought conditions. In fact, the key is to cut numbers down to the carrying capacity and start building fences so that the grass has more time to recover as it grows slowly without rainfall. This is the idea of biological rather than calendar time.

Over time, higher stock density coupled with longer recovery periods allows Ranch B to increase its forage production relative to Ranch A. Each plant gets a chance to grow, and the animals graze those plants more evenly. This means that Ranch B is likely more profitable as it can either run more animals across the entire ranch or eliminate/reduce costs such as feeding as long in the winter.

Start with a fence

Are you Ranch A or Ranch B and which do you want to be? The next question is what to do about it? Ranch B has four paddocks, but in truth, those paddocks were initiated by the first fence. In other words, the place to start is with the first fence. Pick an easy one to build if you can. One fence, instantly means that half of the pasture is now resting. Mathematically that is infinitely better than none of the pasture resting. Then, divide that half by one-half. Over time the goal should be allowing every plant enough time to recover from grazing before being grazed again.

Every ranch is different, but every ranch is the same. Terrains vary, soil varies, base productivity varies but sunshine, water and the magic ingredient of time can result in more forage on your operation.

About the author

Contributor

Sean McGrath is a rancher and consultant from Vermilion, Alta. He can be reached at [email protected] or (780) 853- 9673. For additional information visit www.ranchingsystems.com.

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