What is the definition of rotational grazing?
Simply put, rotational grazing is any grazing regime that involves the rotation of grazing animals through 2 or more pastures, which are then allowed to rest for any given period. The rise of rotational grazing became obvious as we began to understand the downfalls of continuous grazing. While continuous grazing often presents itself as the lowest cost, least daily management option that can (at conservative stocking rates) allow for decent individual animal performance, it has its limitations. In continuously grazed pastures, the grazier has few tools to influence animal behavior, namely the plants which the animals graze, how severely, and at what frequency.Continuous grazing results in selective grazing with certain areas being severely grazed, while others go underutilized. This results in depleted root systems, a decline in plant diversity, the encroachment of more grazing tolerant/increaser plant varieties, increased erosion, depleted soil and often sub-par animal performance and returns per acre.We know that plant growth and root development can be stimulated by defoliation and the hoof impact of ruminants; but we also know that sometimes too much of a good thing, is a bad thing. This is certainly the case regarding the impact of grazing on grasslands. In response, ranchers knew they had to find a way to manipulate grazing pressure to stimulate grass growth, encourage biodiversity, and maintain peak forage quality. Necessity is the mother of invention, and so rotational grazing was born.There is a broad spectrum of systems that fall into the “rotational grazing” category. Each involving varying degrees of grazing densities, duration's and rest periods. Before we dive into the different types of rotational grazing systems, it’s important to note that one size does not fit all environments. Where a certain grazing system may provide positive economic returns in one environment, it may be completely cost prohibitive in another, despite the ecological benefits. Remember though, technology continues to change what’s possible and profitable in agriculture. So, what may be out of reach, as far as management potential, today could be feasible with the development of new technology.
Rotational Grazing Systems
Rotational grazing systems and the terminology around them can be difficult to communicate concisely. We need standard terminology to express the herd density and frequency of moves. The Pasture Project provides very useful guidelines around terminology of various Grazing Systems such as how many cows per acre and how many days per graze. These “levels” of management are defined from the least intensive to the most intensive systems: Continuous Grazing: Single pasture system and no rotation of livestock. This generally requires very conservative stocking rates.Slow Rotational Grazing: 2 or more pastures with moves from every 2 weeks to every few months.Planned Rotational Grazing: Strategic moves every 3 to 10 days to allow for rest and recovery in grazed pastures.Management Intensive Grazing: More structured system where moves are completed every 1 to 4 days. Generally, this requires many permanent pastures in place and temporary fence to create smaller paddocks. Herd densities are typically between 3-14 AU per acre.Mob Grazing: Involves significantly higher stock densities (75-300+ AU per acre) where multiple moves per day are necessary to maintain desired stock densities. Temporary fencing is often used to create small paddocks.Adaptive High-Stock Density Grazing: Utilizes many of the previous mentioned methods of grazing to allow ranchers to adjust herd density to match conditions or meet nutritional needs of livestock.
Benefits of Rotational Grazing
Grass plants and ruminants have co-evolved and are dependent on one another to function optimally. It’s well understood that grasses can give up 50% of their leaf area to a grazing animal without any hinderance to its own root growth. In return, the plant receives fertilizer in the form of dung and urine, its seeds are scarified and firmly planted in the soil through hoof action, and understory plants are given the opportunity to thrive once a dense overstory is thinned, creating opportunities for more plant diversity.If a plant is grazed more severely than 50% (and they often are despite our best management efforts), it must utilize its root reserves and sacrifice root mass to produce new leaves with which to capture sunlight. Plants are equipped to do this, though, and they can put up new leaves in as quickly as 5 days and use them to capture sunlight and store that energy again in their roots which restores that biomass below ground. However, if that new growth is grazed AGAIN, before the roots have had a chance to recover, this is when our grazing and lack of management is actually doing real harm and root systems are depleted and shrunken.The difficulties in grazing management lie in ensuring that plants are grazed no more than 50%... and only one time. But, how does one convince a hungry cow that she should only eat half of one particularly tasty plant and not graze it again until it’s fully recovered down to the roots? Grazing behavior can only be somewhat controlled through manipulating two factors: 1) Grazing duration 2) Livestock density. We use rotational grazing, in varying degrees of intensity, to manipulate these two factors with the goal of changing animal behavior.By changing animal behavior through fencing and movement, we can prevent the severe grazing and re-grazing that takes place under very slow rotations or continuous grazing management systems. Some of the benefits are the following:
- Animals become less selective in their grazing: Rather than eating only desirable plants, they begin to choose less-desirable plants as well. This decreases the competitive advantage of those unwanted increaser grasses and weedy forbs and allows a healthier plant community to develop.
- Harvest efficiency goes up: You’re able to harvest more of what’s produced on each acre and waste less of what is grown. At high enough stock densities, animals begin eating weeds and invasive grasses. They may not be the most palatable plants in the field, but weedy forbs are often very nutritious!
- Soil health improves: As plants are given longer rest periods to recover from grazing events, they are better able to replenish and grow their roots. Plants naturally shed root tissue annually, so larger root area means that more organic material is being released into the soil every year. This root material feeds microorganisms as it breaks down in the soil to eventually become organic matter.
- Increased forage production: Forage production can be expected to improve as soil health improves. Soil fertility is directly linked to organic matter content. Soil organic matter also increases water holding capacity in the soil as well, meaning your soil becomes a better “sponge” to absorb the rain that is received and slowly release it to plants.
- Drought resistance: As root systems become healthier, the soil becomes more drought resistant. For every inch of soil that roots can penetrate, they access .1 to .2 inches of plant available water. That’s like receiving an extra half inch to an inch of rain if roots are 5 inches deeper which is a very achievable goal when pastures are managed correctly.
- Improved herd health: Although often an unintended, improved herd health is a common side effect of rotational grazing. When moving animals more frequently, the rancher sets eyes on each animal much more often than in less intensively managed systems. That means sickness and other issues can be noticed and addressed in a timelier manner. Not to mention that by rotationally grazing, animals are maintaining a much steadier plane of nutrition as they have access to fresh feed regularly.
Of course, these advantages are relative depending on the type of rotational grazing system being used, in what environment, and the complex interactions of grazing animals with the landscape. As stated above, one grazing system does not fit all. High producing pastures are where the greatest returns can be found through implementing more intensive rotations. However, all plants react the same to grazing and most pastures can benefit from additional herd management. It’s just a matter of balancing the costs and returns of additional infrastructure.
How Technology Can Help You Manage Your Intensive Rotational Grazing System
Implementing a rotational grazing paddock design comes at a cost. Usually additional water and fencing infrastructure is needed, whether in the form of permanent or temporary fencing and fixed or mobile water tanks. Any good business wants to measure the increase in production and returns from implementing new methods. This is where a robust recordkeeping and planning system must be in place at the start. It’s important that current pasture performance is known so that projections can be made for the future. If you don’t know your production and utilization per acre before implementing a change, such as installing cross-fencing, how do you know if your returns are adequate to justify installing more?MaiaGrazing allows producers to track grazing data, create forecasts for future stocking scenarios, and track improvements in land performance in a way that adjusts for variance in rainfall. Having analytics at your fingertips that accurately reflect your position on your farm or ranch today, combined with the ability to benchmark those values against how you’ve been positioned in the past, likely under different rainfall conditions, is invaluable. This is even more invaluable when implementing more intensive management practices. As mentioned before, not every piece of land is suitable for the most intensive management, we must consider costs and return on investment.The more intensively we manage a system, the more precise we must be with our decisions. This is true no matter what kind of business you’re in. Most businesses today track inventory, costs, and market conditions to stay competitive and viable. While agriculture is unique in that our grass inventory depends on rainfall and is out of our control, agriculture must operate the same as other businesses in order to maximize profits. As quickly as herd inventory and livestock feed requirements can change, combined with rainfall that’s never consistent, it’s important to have a system in place that can keep up.
