Forages make up a large portion of ruminant diets.
A survey of beef producers revealed that producers who grazed cattle longer had lower costs of production compared to producers who fed more harvested forages.
Thus, the longer we can keep animals out on pastures harvesting their own forage, the greater the opportunity to keep production costs down.
In the upper Midwest, much of the perennial pastures consist of cool-season grasses. These grasses produce most of their growth in spring, grow slowly during mid-summer and, if rainfall is adequate, produce moderate amounts of forage in late summer and early fall.
This uneven forage distribution does not tend to meet forage needs of livestock throughout the growing season.
Managing pastures to have adequate supplies of forage for as long as possible during the year takes planning. The most difficult period for providing season-long forage is mid-summer.
Supplemental pastures during summer can supply forage when forage is normally limiting. Further, use of supplemental pastures allows cool-season pastures rest during mid-summer, giving them time to regrow and accumulate (stockpile) forage for late-summer or fall grazing.
How does a producer manage to have adequate amounts of forage available from July through fall? One approach is to stock pastures lightly in spring.
Forage growth will get ahead of grazing animals but animals will be able to selectively graze and have enough forage to last through the growing season.
This is a viable option for some livestock operations. However, animal production per acre will be well below its potential.
Another option with modest stocking is to set aside acres to produce hay with spring growth. After making the first crop of hay, those pastures can be added to the grazing system. This increases acres available for grazing in summer and fall.
Perhaps the best way to provide late-summer and fall grazing is to remove animals from cool-season pastures during mid-summer.
Some alternative forage management strategies and crops for summer are:
Alfalfa makes an excellent complement to cool-season grass-based grazing systems. Alfalfa is a high-quality legume which grows more during mid-summer and fall than cool-season grasses.
Alfalfa already exists on many farms and can support excellent liveweight gains or milk production.
Initial spring growth of alfalfa occurs when cool-season pastures are rapidly growing. As such, first-cutting alfalfa can be taken for hay.
Use alfalfa regrowth for summer grazing. Graze alfalfa much as you would hay it, with about four weeks’ rest between grazings. On dairies where forage intake is critical, move animals at least daily. In beef and sheep systems, less intensive systems can work well.
Bloat can be a problem while grazing legumes and should not be ignored. Manage to minimize the risk of bloat.
Do not move hungry animals to lush alfalfa – feed animals hay (so they are not as hungry) before moving them to a new pasture. Don’t move animals on to wet alfalfa (from dew or rain).
Feed grass hay in alfalfa pastures. Supply animals with a bloat block or bloat guard. Perhaps the most critical point is to observe animals often. Be aware but don’t be afraid of bloat.
Warm-season forages produce the majority of their growth during mid-summer. This makes them fit nicely with cool-season grass pastures.
Both warm-season perennial and warm-season annual pastures can be used to stockpile cool-season pastures for late-summer and fall use.
Native warm-season grasses are perennials. Thus, they can persist for many years with good management.
Native warm-season grasses grow rapidly and produce lush, vegetative forage during mid-summer. Keep animals off of the warm-season pastures in the spring while cool-season pastures are actively growing. Animals grazing warm-season pastures in mid-summer can gain two pounds per day.
Summer annual grasses, such as sudangrass or pearl millet, can also offer productive mid-summer grazing.
They produce vegetative growth during mid-summer and are a good complement to cool-season pastures. Summer annuals can be expensive as a result of annual seeding.
Good fertility management and rotational grazing and/or staggered planting dates are needed to make summer annuals viable.
The sudangrasses (all sorghum species) can cause prussic acid poisoning if grazed after a killing frost. Pearl millet will not cause prussic acid poisoning. As a general rule, pearl millet produces better on lighter soils and sudangrass better on heavier soils.
Summer nitrogen fertilization
Fertilizing pastures is often overlooked as a management tool to increase summer forage production. Nitrogen (N) fertilizer will increase plant growth.
In many instances, N is applied to pastures in spring. If the pastures are harvested for hay, this is a way to increase hay production. Under grazing, forage is often abundant in spring. Additional growth at this time may not be efficiently used by grazing animals.
This can result in poor return from money invested in fertilizer. It may make sense in a grazing operation to apply fertilizer in late June.
Additional forage production will occur in mid-summer to late-summer, when additional forage is needed. Because most pastures are underused in spring and overused in summer, one application of 50 to 80 pounds N per acre in mid-June to mid-July may be profitable in many pasture systems.
Forage legumes in grass pastures
Legumes benefit grass pastures by providing N to grasses, by improving distribution of forage growth through the grazing season, by increasing animal intake and by improving animal performance.
To effectively use and maintain legumes in pasture systems, attention to soil fertility and grazing management are needed.
Forage legumes offer a number of advantages for pastures. However, there are several challenges for using legumes in pastures.
Legumes generally have poor persistence (particularly under continuous grazing) and low tolerance to poorly drained soils and low soil fertility. In addition, many legumes can cause bloat. As such, a grass/legume mixed pasture is desirable.
While animals are grazing alternative forages in summer, cool-season pastures are growing slowly and are stockpiling forage for grazing in late summer or fall.
Managing spring growth and including summer grazing alternatives helps provide forage in mid-summer and fall and helps keep pastures vigorous. In addition to the options discussed above, brassica species and corn residues can also be used to keep animals grazing longer in fall.
There is not a single best way to manage forage systems for all farms. Consider some of the options suggested, consider when you have forage shortages and excesses and see what kind of pasture management system might best fit your farm.
By diversifying your pasture system, you can reduce the impact of seasonal weather and growth fluctuations and give yourself the best opportunity to have abundant amounts of high-quality forage available for as long as possible during the growing season and help make grazing a profitable part of your management systems. FG