By Victor Shelton, NRCS State Agronomist/Grazing Specialist
I hear people mention the “lazy days of summer,” but I’ll have to admit that has never really seemed valid for me. I’m glad that the days are long, because quite often, I need every minute of daylight and then some. Precarious weather seems to be timed quite well to disrupt plans and tasks. This is only doubled in difficulty when you are also holding down an off-farm job, which always seems to take you away when the weather is perfect. You have to just shut your mind off, focus on the task at hand and not dwell on the farm work that must be completed. I know that I am not the only one this happens to.
I had something sent to me recently and I thought it made some good points. When time is sparse, as it seems it often is, then we need to be as efficient as possible and that includes pasture management. The brief synopsis included four never fail rules of grazing. Let’s explore these.
1 — Never let seed heads form on plants.
I often talk about three major stages of forage growth. The immature stage is early in the year when forages are high in moisture and usually nitrogen and have less structural components. Next is the vegetative stage of rapid growth with some plants in the boot stage and thinking about sending up seed stalks. Finally, is a maturing stage, where seed is produced and eventually matures if not removed. Ideally, you want to keep the forages in that second stage as long as possible. During this stage, nutrition is good, bite size is good, and the plant is continuing to grow leaves. Once seed heads start forming, a lot of energy is shifted to seed production and away from the leaves and roots.
We can keep most plants in vegetative form by rotating livestock across them on a regular basis and then providing adequate rest before grazing again. Allocating out smaller amounts helps to provide more even grazing and less patch grazing and avoidance. Grazing helps to delay seed head production and sometimes, if the forages are not stressed, there can be a reduced amount seed heads.
If needed, a timely clipping can really slow down seed head production and help promote regrowth. This is best done after the grazing event to even the stand. If it hasn’t been grazed yet and it is starting to mature, a quick grazing over it can help to reset it or hay could be taken off the site for winter use if it won’t be needed for grazing in the near future.
Though quality of the forage will be better if seed heads are controlled, there are situations, especially when you are trying to build soil organic matter, when letting a field sit idle and mature is good. This allows sufficient time for the plants to fully express themselves and allows for maximum root depth. These stands can then be strip grazed allowing the livestock to eat the best and lay down the rest.
2 — Never let livestock graze more than 7 continuous days on a pasture.
This is actually a really good rule of thumb. When animals are left too long on an allocation, they will eventually stop grazing existing vegetation and move to regrowth. Specifically, new regrowth from what was just grazed.
Why? Because it is generally a higher nutritional plane than the older growth. The forage needs some R&R before being grazed off again to help maintain the plant and the quality of the sward. When the livestock switch to new regrowth, what they then avoid tends to get ranker and avoided even more. Some grazing ruminants have the ability and desire to be more selective and perhaps have more sensitivity to nutritional needs, like sheep, and they’ll switch to regrowth within about 3 days. Sheep, therefore, should really be rotated every 3 days. Longer grazing periods tend to enhance differences in growth with more spots overgrazed and under grazed and very little in between that is considered more ideal. You also start seeing more undesirable species appearing and desirable species being reduced.
3 — Never graze closer than 3 inches.
I often mention trying to maintain “stop grazing” heights. Those are the shortest forages present, not the tallest. It’s important to maintain a certain amount of leaf growth to keep the “solar panel” in good working condition. When a minimum amount of forage is maintained, the plants are also able to continue to support their root system better, keep the ground covered better, keep the soil cooler and usually help support more regrowth. Stop grazing height is the amount of residual live plant material left behind after a grazing event. If some of the forage has been grazed down to 1.5 inches, then that is the residual height and, in most cases, it is considered overgrazed at this point. Stop grazing heights vary according to the species being grazed. Short cool season forages like Kentucky bluegrass and white clover are more tolerant to closer grazing. Most tall cool season forages like orchardgrass and tall fescue are best kept at least 4 inches. Tall warm season forages such as big bluestem, Indiangrass and Switchgrass need to have a minimum of six inches but do better with 8 to 10 inches. That goes for grazing and mechanical harvest. The exception to the rule is post dormancy early winter. Forages will tolerate a closer grazing then and that opens an opportunity to improve conditions for frost-seeding clover mid-winter.
4 — Never return to a pasture in less than 30 days.
On average, this is a good rule. That time frame is usually enough under normal conditions to get adequate regrowth to be able to graze the field again. Quite often during the spring rapid growth period, that is too long. I prefer to keep rotating pastures in the spring until that first paddock is ready to be grazed again and then start over. If you don’t do that, there will be a lot more fields potentially getting out of control and rule number one goes out the window. Later in the season, when things often get hotter and drier, the rest period is usually closer to 45 to 50 days. It’s best to just keep an eye on the forages, reassess them on a regular basis and move according to the amount of forage present as suggested in rule 3.
There are still dry areas around. There are also areas that were blessed with enough rain that now when it is turning drier, the plants are very quickly reacting to it. After being wet for extended periods of time, plants get lazy and some don’t put down good, deep roots. So, when it does turn dry, they tend to be affected more than usual.
There is a lot about grazing that is more art than science and a whole lot of “it depends.” Keep your eye on the forage. Remember, it’s not about maximizing a grazing event, but maximizing a grazing season! Keep on grazing!