The traditional approach to grazing has been to put animals in a pasture at the beginning of the season and let them stay there until they run out of feed. This method is called “set stocking,” and it results in simultaneous overgrazing and undergrazing of plants in the same pasture.
The reason set stocking causes overgrazing and undergrazing at the same time is because critters are sort of like children in a candy store: When they’re set stocked, they eat what they like the most and ignore the flavors they don’t like. Some plants are constantly being grazed, whereas others aren’t touched. Interestingly, the result of both overgrazing and undergrazing is the same — the plants lose energy and don’t perform at their peak potential. Ultimately, both scenarios can kill the plants.
By employing managed grazing — also called rotational grazing, management-intensive grazing and planned grazing — you control the flock’s access and grazing time, thereby obtaining peak plant performance, which in turn results in peak animal performance. The trick to this is to subdivide your pasture into smaller pieces, known as paddocks, and to time your flock’s movements through the paddocks according to how the grass is growing.
Grazing management is a complex skill that takes time to master, but the payoff is well worth the effort. Finding a mentor who uses managed grazing, even if it’s a cattle grazier, will hasten the learning process. Many states now have organized grazing groups, which your county extension agent can help you find. The local office of the USDA National Resources Conservation Service also can be a valuable place to learn about managed grazing, and may also be able to help provide cost-share funding for installing needed fencing and watering systems.
Some forage plants, such as alfalfa, can’t stand the pressure of the continuous grazing that occurs in a set-stocked pasture, but they can survive hard grazing for short periods. Alternating paddocks allows these plants to compete. In fact, all desirable forage plants grow much better when they are grazed hard and then given a period of rest.
You’ll also find that managed grazing gets your sheep to eat better than they would on a set-stocked pasture. Sheep prefer not to feed continually in the same place. They like fresh pasture that hasn’t been walked on, and managed grazing keeps them on fresh pasture regularly.
Timing the flock’s movements
The key to grazing management is time. There are ideal points for beginning and ending grazing — or mechanical clipping if the grass is getting too long but you’re not ready to bring the flock back around. By controlling your flock’s access to pasture through carefully timed movement, you can maintain growth between points C and B.
Animals should be moved from a paddock before they’ve grazed off 50 to 60 percent of its forage, because most forage plants reach their maximum vigor and growth when no more than 60 percent of their leaf surface is removed during any grazing period. For example, if the sheep enter a paddock when the forage is 6 inches high, then they should be removed while at least 2 1/2 inches is left standing.
The last time-related issue to consider is the rest period. After you move a flock to another paddock, the one you’re leaving needs enough time to grow back to the starting height. The rest period varies by season. In early spring it may be as short as seven to 10 days; in the height of summer, it may take 45 days.
During the spring, when the grass is growing rapidly, you can move the flock through the paddocks quickly and don’t need to worry about taking the full 50 to 60 percent of the forage each time. Just let the flock lightly graze 20 to 30 percent, then move them to the next paddock.
In the latter part of the growing season, when the rest period is getting longer, slow down their movements between paddocks so they take the full 60 percent.
How well you can control these time factors depends primarily on how many paddocks you have available.
How many paddocks do you need? As paddock numbers increase, the time spent in each paddock decreases and the possible rest time before the paddock is regrazed increases. So, the answer is, as many as you can reasonably create. At the very minimum, shoot for four paddocks — eight is even better, and 12 provide lots of flexibility and control through all kinds of conditions.
In the past, because of added expense and labor, fences for paddocks were often neglected, but with today’s modern electric fencing, there’s really no excuse not to create subdivided paddocks. These barriers don’t have to be as heavy or as high as perimeter fences, and they also don’t need to be predator- or dog-proof. In fact, they can be created with temporary polywire and step-in posts.
The advantage of paddocks
Sheep graze smaller paddocks more evenly and have less of a tendency to pick and choose than they would in one larger pasture. When the area has been adequately grazed, the sheep are moved to a fresh paddock. When you move the sheep out of a paddock, the grass will receive the rest it needs to keep growing at its fastest growth rate. If the rest period is adequate — usually at least 28 days — the sheep are not forced to eat as close to the ground, because the forage is at a better height, thus reducing the parasite eggs they pick up while grazing. An old Scottish shepherd’s saying goes, “Never let the church bell strike thrice on the same pasture.”
When managing paddocks for sheep, try not to let the grass get too tall before you turn in the sheep or they’ll trample more than they eat. When the grass has reached a height of 6 to 8 inches, it’s an ideal time for the sheep to enter the paddock. (If you happen to be grazing your sheep with cattle or horses, begin grazing the paddock when the grass is 8 to 12 inches tall.) Occasionally, especially in the spring, some paddocks may get too long; you can mechanically clip — or mow — these paddocks for hay or just leave the clippings on the field as green manure.
Excerpted with permission from Storey’s Guide to Raising Sheep by Paula Simmons and Carol Ekarius (Storey Publishing, 2009).