Cool-season perennial grasses for horse pastures
- Meadow fescue, endophyte-free tall fescue and Kentucky bluegrass are recommended for Midwest horse pastures.
- Kentucky bluegrass, timothy and meadow fescue were the most preferred grasses by horses.
- Smooth bromegrass and timothy didn't last in horse pastures.
Cool-season grasses in the Midwest
Cool-season grasses are the basis of productive pastures in the Midwest and Eastern United States. As selective grazers, horses may limit the yield and persistence of some pasture grasses. Their lips and tongues allow them to graze plants to a shorter height than other livestock species.
As a result, forage yield and consistent growth are key when selecting grasses for productive pastures, especially for selective grazers like horses. We evaluate the forage yield and persistence, and horse preference of cool-season grasses while being grazed by horses.
Meadow fescue, tall fescue (endophyte-free) and Kentucky bluegrass should be planted in Midwestern horse pastures as they strike a balance between forage persistence, yield, quality and horse preference.
What did we do?
We grazed four adult horses on the following species in pure stands:
- Creeping foxtail
- Kentucky bluegrass
- Meadow bromegrass
- Meadow fescue
- Reed canarygrass
- Perennial ryegrass
- Smooth bromegrass
- Tall fescue
The horses grazed the research area for three consecutive days (8 hours per day) each month from May to October in 2010 and May to September in 2011.
- We evaluated grass maturity and persistence, measured yield and quality and then grazed the horses when most tall growing grasses reached 8 inches.
- We visually assessed preference and persistence after each grazing event.
- Following grazing, we removed manure, mowed remaining forage to 3 inches and allowed it to re-grow.
- We fertilized grasses with nitrogen in early April and mid-June and applied broadleaf herbicide once a year in spring.
What did we find?
- Under horse grazing, orchardgrass, meadow fescue, tall fescue and Kentucky bluegrass were the most persistent (best ground cover) and highest yielding grasses.
- Smooth bromegrass, creeping foxtail and timothy were the least persistent and lowest yielding grasses.
- Kentucky bluegrass, timothy and meadow fescue were the most preferred grasses.
- Meadow bromegrass, creeping foxtail, reed canarygrass and orchardgrass were less preferred.
Persistence (percent ground cover), preference (percent removal) and yield of 11 different grass species rotationally grazed by horses in 2010 and 2011
|Grass species||Percent ground cover (end of year 2)||Horse preference (2 yr. avg.)||Yield (2 yr. avg.) tons/acre|
During the 2010 (April through October) and 2011 (May through September) grazing seasons, monthly air temperatures were near historical average.
There was more rainfall during both grazing seasons compared to the historical records.
Drought conditions in late September and October of 2011 limited grass regrowth and prevented grazing in October 2011.
Reed canarygrass, smooth bromegrass and timothy won't regrow well if cut or grazed during stem lengthening. During this phase, regrowth becomes interrupted.
More persistent species such as orchardgrass can continue to regrow during stem lengthening.
In general, we recommend starting grazing when tall, cool-season grass pastures are at 6 to 8 inches in height. This recommendation will likely result in reed canarygrass, smooth bromegrass and timothy being at the stem lengthening stage at the start of each rotational grazing period.
As a result, these plants may be particularly prone to poor persistence. Avoid grazing horses during the stem lengthening stage or avoid using these grasses in pastures.
Plant forage with similar preference ratings in horse pastures to maximize forage use.
Mixtures that result in uniform grazing will help maximize forage use and reduce pasture maintenance and related expenses.
See the grass comparison table for specific preference values among species.
Orchardgrass, tall fescue, meadow fescue and Kentucky bluegrass were the highest yielding grasses and averaged 4.0 to 5.4 tons per acre each year. These same four grasses were also the most persistent under horse grazing.
Creeping foxtail, smooth bromegrass and timothy were the lowest yielding grasses.
Most cool-season grasses don't yield as much during the warm and drier summer months. We refer to this change in forage growth as "summer slump."
But, in this study, the highest yields for most grasses occurred during summer. Of the total forage yield, 40 percent occurred in the summer for 2010 and 83 percent for 2011.
In pasture systems, you can maintain immature plants by frequently grazing horses and routinely mowing. This practice allows for similar plant growth rates throughout the season.
Maintaining immature plants and the rainfall we saw during the study likely explains the increase in production observed during the summer months and the lack of a summer slump.
Overall, creeping foxtail was the lowest quality cool-season grass, with low crude protein (CP) and neutral detergent fiber digestibility (NDFD) amounts, and high neutral detergent fiber (NDF) values. Levels of non-structural carbohydrate (NSC) were similar among the grasses in spring and fall.
- Perennial ryegrass, quackgrass and smooth bromegrass had higher CP levels, while Kentucky bluegrass, orchardgrass, creeping foxtail and timothy tended to have lower CP levels.
- Although few grasses had consistently high or low NDF levels, quackgrass tended to have lower NDF values compared to creeping foxtail and smooth bromegrass.
- Perennial ryegrass and meadow fescue tended to have greater NDFD levels, while creeping foxtail and Kentucky bluegrass were lower.
- During the summer, timothy, Kentucky bluegrass, meadow fescue and perennial ryegrass had higher amounts of NSC, while meadow bromegrass, orchardgrass and reed canarygrass were lower.
Horses are selective grazers, but we know little about what drives horse preference in a pasture system. In this study we found that in 2010:
- NSC level positively correlated to horse preference.
- There was a trend for NDFD level to be positively correlated with preference.
- There was a trend for NDF level to be negatively correlated to horse preference.
- Crude protein and maturity were not correlated to horse preference.
In 2011, we found that no forage nutritive values or maturities correlated to horse preference. It's widely accepted that horses (and other livestock) prefer forages that are lower in fiber (NDF) and higher in carbohydrates (NSC). The lack of consistent correlation between forage nutritive value and horse preferences in 2011 highlights how complicated horse preference is.
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This project was funded by the University of Minnesota Agricultural Experiment Station, the University of Minnesota Grant‐In‐Aid Program, and Midwest Forage Association.
Reviewed in 2019