Legumes increase yield, improve quality of grass-based forage systems
This is the time of year when legumes, such as red clover and white clover, can be frost-seeded into pastures by broadcasting seeds over the frozen ground. This no-till method works seeds into the soil as it freezes and thaws during the transition between winter and spring.
Fields sown with clovers now will produce high-quality forage for livestock producers in summer. Adding legumes to grazing pastures can improve animal performance, soil health and forage production. The legumes will increase the yield and protein of the forage while fixing nitrogen.
In a well-managed rotational grazing system, the forage supply should be monitored closely and adjusted to the appropriate stocking rate during specific times. Controlled grazing is an important factor to improve utilization.
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Choose a species based on traits
Not all clovers are the same. The type of clover used should be determined by what type of livestock you plan on grazing, your soil type and your environment. Concentrate on the quality and traits certain species offer and match them to your situation.
Monitor dry matter production instead of just plant height
Recommended pasture heights should be 4 to 5 inches for cattle, and rotational grazing systems should also focus on pasture mass. For sheep, the height can be shorter. At least 2½ to 3 inches for sheep will achieve maximum feed intake. This corresponds to around 1,350 to 1,800 pounds of dry matter per acre.
The target pasture mass before grazing correlates with the target post-grazing residual mass and rotation length. This varies by the season and livestock. In seasonally calving dairy operations, target pasture cover for dry cows is recommended to be in the range of 1,800 to 2,200 pounds dry matter per acre and generally in the range of 2,500 to 2,700 pounds of dry matter per acre for wet cows.
Give plants a rest
When plants are grazed too short, two things happen. First, the plant’s energy reserves are depleted, increasing the timeframe for a pasture to recover. So what may have been a 30-day rest period could extend to 40 days. Second, plants are less resilient and more susceptible to drought and cold weather. The rate at which livestock can effectively graze pastures also needs to be considered. Cattle have a tough time eating enough dry matter if the pastures are shorter than 2 inches.
Grasses accumulate carbohydrates in their bases and generally can be grazed closely as long as they are given enough time to recover. The recovery period is also related to rotation length, which is generally driven by the leaf appearance rate and fully expanded leaf numbers. If the plants are defoliated before recovery is complete, lack of energy will result in slower regrowth, prolonging the recovery period and eventually leading to plant death.
Time grazing when plants are at their highest nutritional value
To make the most out of a rotational grazing system, producers need to graze the regrowth when forage is at its optimum fiber, energy and crude protein contents.
There is substantial variation in the forage due to moisture, temperatures and individual pastures. Grazing management must consider needs such as pasture cover targets, feed demand requirements and pasture quality. The leaf stage of the grasses has been used as an effective indicator of when a pasture is ready to graze. As an example, in spring, perennial ryegrass produces a fully expanded leaf every eight to 10 days with a lifespan of three to four weeks. The best time to graze ryegrass pastures is at the three-leaf stage. Increasing rotation length to graze pastures after the three-leaf stage reduces pasture quality as older leaves begin to deteriorate. Grazing pastures repeatedly at the two-leaf stage will decrease forage yield and animal production.
Use clovers to increase feed intake
Forage intake of grazing animals can be restricted by the high moisture and fiber contents of the forage. High legume content in pastures is desirable for greater forage intake and animal performance. Legumes have a higher nutritive value than grasses. At the same stage of maturity they will have lower fiber concentrations, more energy and higher protein than grasses.
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