WEST PLAINS, Mo. — Each spring the emergence of cool season grass seedheads is a sign of an advancing season and the gradual decline of forage quality in pastures and hay fields. All grasses experience a decline in forage quality with the development of reproductive structures.
When grasses develop reproductive structures, leaf growth slows down, and then stops all together. The photosynthetic sugars are redirected to develop the reproductive structures and seeds. The reproductive stems contain fewer quality cell contents and develop large amounts of structural fiber. All of this results in decreased forage quality.
One way that livestock producers can improve this situation is to remove seedhead tillers early in the growing season to maintain forage quality. This can be done with management-intensive grazing; which allocates a small amount of pasture to the livestock every day or two. If grass grows too quickly to make this happens, another option is to clip the paddock to remove the seedhead, which is referred to as “resetting” the paddock.
Another option to remove seedheads is to bale hay. The seedheads will be in the hay bale, resulting in lower quality hay. However, removing seedheads will allow the plant to resume leaf growth and result in higher quality pastures and hayfields later in the season.
One issue we have with our commonly grown Kentucky 31 tall fescue is that it is endophyte-infected and seed production increases ergot alkaloid concentrations. This variety becomes toxic to cattle as a result. The common strain of the endophyte produces ergot alkaloids, like ergovaline, that are toxic to livestock.
Livestock that consume toxic, endophyte-infected tall fescue typically experience symptoms referred to as fescue toxicosis. These symptoms can include reduced feed intake, lower milk production, decreased rate of gain, narrowing of blood vessels restricting blood flow, reduced pregnancy rate, and elevated body temperature to name a few.
There is no single management practice that reduces the impact of fescue toxicosis on livestock, so managing it involves alkaloid management and incremental alleviation. Incremental alleviation involves the additive effect of multiple management practices.
These practices could include clipping tall fescue seedheads, using Chaparral (active ingredient metsulfuron) herbicide to suppress seedheads three weeks prior to seedhead emergence, interseeding legumes or other grasses into the stand, rotation to summer pasture, feed supplementation and managing against excess nitrogen applications on fescue. Excessive nitrogen applications can lead to higher ergovaline levels.
One other option to consider for management of fescue toxicosis is renovation of the paddock to a novel endophyte fescue. Novel endophytes offer the same benefits to the plant as the endophyte in Kentucky 31 tall fescue, without the toxicity issues for livestock. These also provide much greater stand persistence than endophyte-free varieties.
To find out more about managing tall fescue on your property, contact an MU field specialist in agronomy. In southern Missouri, they are Tim Schnakenberg SchnakenbergC@missouri.edu 417-357-6812; Jamie Gundel GundelJ@missouri.edu 417-778-7490; and, Sarah Kenyon email@example.com 417-256-2391.
— Howell County University of Missouri Extension
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